Drug-eluting Stents Found Safe, Superior To Bare Metal Stents, Study Suggests

Drug-eluting stents were safe and superior to bare metal stents in preventing death and heart attacks among 262,700 "real-world" patients enrolled in a nationwide registry of cardiovascular disease, according to researchers from Duke University Medical Center.

The findings were presented today at the i2Summit at the American College of Cardiology's 58th Annual Scientific Session. They also appear online in the Journal of the American College of Cardiology.

The study is the largest of its kind to date and may end years of controversy over the safety of the devices.

"We hope these findings will finally lay to rest any doubt about the safety of drug-eluting stents," says Pamela Douglas, M.D., a cardiologist and member of the Duke Heart Center at Duke University Medical Center and the lead author of the study. "Our results clearly show that drug-eluting stents are indeed safe."

Stents are small tubes that can prop open blocked coronary arteries. The earliest versions were made of bare metal mesh, but later models were designed to release a medication that could suppress restenosis, or the growth of new tissue that could cause the artery to clog up again. Physicians have been debating their relative merit for years.

After initially proving more effective than bare metal stents in preventing restenosis, drug-eluting stents suffered a setback when recent clinical trials found them associated with higher long-term death rates. Those findings led to warnings from the Food and Drug Administration and confusion over which option is better.

Douglas and colleagues followed patients over age 65 enrolled in the National Cardiovascular Data Registry who had received stents from 2004 through 2006. Most of the patients had received a drug-eluting stent; only 17 percent were implanted with the bare metal variety. Investigators matched the patients' data with their Medicare claims and followed them for two and one-half years, measuring rates of death, heart attack, stroke, bleeding and the need for additional artery-opening procedures.

They found that over the 30-month period, patients in the drug-eluting stent group had a 25 percent reduction in death and 24 percent reduction in heart attacks, when compared with those who received bare metal stents, but no significant difference in the incidence of stroke, major bleeding or need for additional artery-opening procedures.

Douglas says the study is important on several fronts. "First, the data show that over a two and one-half year follow up, drug-eluting stents are safe among patients in a real-world, highly variable environment. Patients who enroll in clinical trials are generally younger, healthier and on fewer medications that the population at large, and that means that clinical trials can generate findings that may not hold up in larger, more variable, community populations," says Douglas.

"In addition, we believe this is the first time that anyone has been able to link so much clinical data with Medicare claims. What that essentially has given us is an excellent model for future post-marketing evaluation," says Douglas, who adds that such studies may be particularly attractive to payers, health care policy makers and anyone interested in health care reform who needs real-world data, as opposed to that generated by clinical trials.

The study was funded by the Agency for Healthcare Research and the ACC's National Cardiovascular Data Registry.

Colleagues from Duke who helped with the study include senior author Eric Peterson, Lesley Curtis, J. Matthew Brennan, Ghazala Haque, Kevin Anstrom, Eric Eisenstein, David Dai, David Kong, Bradley Hammill and David Matchar. Additional co-authors include Ralph Brindis, of Kaiser Permanente and the American College of Cardiology; and Art Sedrakyan, of the Agency for Healthcare Quality Research.

Drug-eluting Stents Found Safe, Superior To Bare Metal Stents, Study Suggests

Drug-eluting stents were safe and superior to bare metal stents in preventing death and heart attacks among 262,700 "real-world" patients enrolled in a nationwide registry of cardiovascular disease, according to researchers from Duke University Medical Center.

The findings were presented today at the i2Summit at the American College of Cardiology's 58th Annual Scientific Session. They also appear online in the Journal of the American College of Cardiology.

The study is the largest of its kind to date and may end years of controversy over the safety of the devices.

"We hope these findings will finally lay to rest any doubt about the safety of drug-eluting stents," says Pamela Douglas, M.D., a cardiologist and member of the Duke Heart Center at Duke University Medical Center and the lead author of the study. "Our results clearly show that drug-eluting stents are indeed safe."

Stents are small tubes that can prop open blocked coronary arteries. The earliest versions were made of bare metal mesh, but later models were designed to release a medication that could suppress restenosis, or the growth of new tissue that could cause the artery to clog up again. Physicians have been debating their relative merit for years.

After initially proving more effective than bare metal stents in preventing restenosis, drug-eluting stents suffered a setback when recent clinical trials found them associated with higher long-term death rates. Those findings led to warnings from the Food and Drug Administration and confusion over which option is better.

Douglas and colleagues followed patients over age 65 enrolled in the National Cardiovascular Data Registry who had received stents from 2004 through 2006. Most of the patients had received a drug-eluting stent; only 17 percent were implanted with the bare metal variety. Investigators matched the patients' data with their Medicare claims and followed them for two and one-half years, measuring rates of death, heart attack, stroke, bleeding and the need for additional artery-opening procedures.

They found that over the 30-month period, patients in the drug-eluting stent group had a 25 percent reduction in death and 24 percent reduction in heart attacks, when compared with those who received bare metal stents, but no significant difference in the incidence of stroke, major bleeding or need for additional artery-opening procedures.

Douglas says the study is important on several fronts. "First, the data show that over a two and one-half year follow up, drug-eluting stents are safe among patients in a real-world, highly variable environment. Patients who enroll in clinical trials are generally younger, healthier and on fewer medications that the population at large, and that means that clinical trials can generate findings that may not hold up in larger, more variable, community populations," says Douglas.

"In addition, we believe this is the first time that anyone has been able to link so much clinical data with Medicare claims. What that essentially has given us is an excellent model for future post-marketing evaluation," says Douglas, who adds that such studies may be particularly attractive to payers, health care policy makers and anyone interested in health care reform who needs real-world data, as opposed to that generated by clinical trials.

The study was funded by the Agency for Healthcare Research and the ACC's National Cardiovascular Data Registry.

Colleagues from Duke who helped with the study include senior author Eric Peterson, Lesley Curtis, J. Matthew Brennan, Ghazala Haque, Kevin Anstrom, Eric Eisenstein, David Dai, David Kong, Bradley Hammill and David Matchar. Additional co-authors include Ralph Brindis, of Kaiser Permanente and the American College of Cardiology; and Art Sedrakyan, of the Agency for Healthcare Quality Research.

New Mexican Health-care Program Successful At Reducing Crippling Health Care Costs

Seguro Popular, a Mexican health care program instituted in 2003, has already reduced crippling health care costs among poorer households, according to an evaluation conducted by researchers at Harvard University in collaboration with researchers in Mexico.

The study was designed and led by Gary King, David Florence Professor of Government and director of the Institute for Quantitative Social Science at Harvard. The results are published in the current issue of The Lancet.

"The success of Seguro Popular in reducing catastrophic health expenditures is remarkable," says King, "not least because governmental money spent on the poor in many countries rarely reaches the intended recipients."

King's study of about 500,000 people is the largest-ever randomized health policy experiment. It features innovative research designs and statistical methods he and his colleagues developed that increase what we learn from an evaluation while simultaneously saving a great deal of money. The design includes several failsafe components that preserve the experimental randomization even if politics or other problems intervene, including those which have ruined most previous large scale public policy evaluations. The approach is now being implemented or considered for evaluations of many other public policy programs around the world.

Passed in 2003, Seguro Popular was developed to provide health care to 50 million Mexicans who otherwise lack coverage. Voluntary enrollment in the program, at no cost to the poor, provides access to health clinics, drugs, regular and preventative medical care, and the money to pay for it all. The program's primary goal is the reduction of catastrophic health expenses, those exceeding one-third of a household's yearly disposable income.

About a half a million people in 118,569 households were included in this study, which was conducted over 10 months. In the treatment clusters, 44 percent of households reported participating in the program, compared to 7.3 percent in control communities, which was approximately as expected. Among participating households, those suffering catastrophic health expenses were reduced by almost 60 percent, contributing to a 30 percent reduction in catastrophic health expenses across treatment communities.

The evaluation also highlighted areas in which the program was ineffective. Contrary to prior non-randomized studies, the researchers found no increase in utilization of health services, although longer-term research may show an increase. Health outcomes will also take longer to show an effect.

Before the program was instituted, 174 communities were paired up based on having similar background variables, such as the health of the community, size, and the number of schools. Then one community within each pair was randomly chosen to receive treatment: Families were encouraged to enroll in Seguro Popular, health facilities were built or upgraded, and medical personnel, drugs, and other supplies were provided. In the other community within each pair, no changes were made.

"One advantage of this design is that if one of the communities was to drop out of the study, due to interventions by politicians or for other reasons, the paired community would be removed as well, and the balance between the treated and control groups would not be affected. In contrast, classical randomized experiments are destroyed when even one community is lost. The matched pair design also decreased the margin of error to as little as one-sixth of what it would be with traditional experimental methods," says King. "That's the equivalent of collecting many more respondents, or randomizing throughout many more communities, for the same cost."

Seguro Popular in Mexico covers about the same number of people as are uninsured in America. King points out that there may be lessons for other countries to learn in the success of Seguro Popular.

King's co-authors were Emmanuela Gakidou of the University of Washington; Kosuke Imai of Princeton University; Jason Lakin, Clayton Nall, and Nirmala Ravishankar of Harvard; Ryan Moore of Washington University in St. Louis; Manett Vargas of the Ministry of Health in Mexico; Martha María Téllez-Rojo and Juan Eugenio Hernández Ávila of the National Institute of Public Health in Mexico; Mauricio Hernández Ávila of the Ministry of Health in Mexico and the National Institute of Public Health in Mexico; and Héctor Hernández Llamas of Conestadistica. Gakidou, Imai, Lakin, Nall, Ravishankar, Moore, and Vargas are all King's current or former students and affiliates at the Harvard Institute for Quantitative Social Sciences.

The research was funded by the Mexican Ministry of Health, the National Institute of Public Health in Mexico, and the Harvard Institute for Quantitative Social Science.

Partner Behavior Better Predicts STD Risks

Risky behaviors such as not using condoms or having sex with multiple people put young adults at risk for contracting sexually transmitted diseases, but perhaps not as much as the characteristics of their sexual partners, University of Florida researchers say.

The findings, which UF and University of Pittsburgh researchers report in the April issue of Sexually Transmitted Diseases, could help health-care providers better screen patients for STD risks, said Stephanie A. S. Staras, Ph.D., a UF assistant professor of epidemiology and health policy research in the UF College of Medicine.

"If you are choosing high-risk partners, you are much more likely to have an STD, even when we account for your condom-use patterns," said Staras, the lead author of the study. "The theory is simple: You need to have sex with someone who has an STD to get an STD. Based on the prevalence of STDs in the United States, it seems like the public may not fully understand their risk."

The study examined the sexual activities, partner characteristics and STD diagnoses of 412 subjects between the ages of 15 and 24. Among the subjects whose partners were categorized as high-risk, half were diagnosed with an STD. By comparison, about 40 percent of the young adults whose own behaviors were labeled as high-risk were diagnosed with an STD.

According to the Centers for Disease Control and Prevention, about 19 million people in the United States contract STDs each year. About half of them are between the ages of 15 and 24.

Health-care providers often ask patients about their own sexual behaviors, but inquiring only about a person's own behaviors may cause some patients to slip through the cracks, Staras said. For example, some subjects in the study reported very low-risk behaviors but were having sex with very high-risk partners.

Adding a few simple questions about partner characteristics during STD screenings could help providers catch more patients who need to be tested and educated about condom use and other protective measures, Staras said.

"Partner selection is an area of STD prevention that could complement what we are already doing with promoting condom use, and could possibly really help people," Staras said. "If somehow we could convince individuals to incorporate this information in a meaningful way into their decision-making, then we could reduce STDs."

UF researchers measured five specific characteristics to gauge how risky certain partners were. These characteristics included whether the partner has a problem with marijuana or alcohol, was at least five years older or younger, had been in jail, had sex with other people in the past year or had an STD in the past year.

The researchers then created a composite, totaling up the number of negative partner characteristics for each subject and comparing them against the number of each person's own individual risky behaviors, which ranged from how often they used condoms to how many people they had sex with.

Overall, researchers found considering all of the partner characteristics together was the strongest predictor for STDs. Young adults whose partners had five or more risk characteristics were three times more likely to have an STD than those whose partners had no more than two characteristics.

Of these characteristics, the most telling were if a partner already had an STD and if a couple had an age difference of more than five years. Subjects whose partners were five years older or younger than them were more than twice as likely to be diagnosed with an STD than those whose partners were around the same age, the researchers found.

"It's all about the risk of the partner and sometimes we forget that," said Richard A. Crosby, Ph.D., the DDI endowed professor and chairman of the department of health behavior at the University of Kentucky and a co-director of the Rural Center for AIDS/STD Prevention.

But Crosby, who was not involved in the UF study, said it's also important for people to remember that the risks mentioned in the study are just generalizations, not set-in-stone giveaways for STDs.

"From a public health perspective, it's important to understand these findings," he said. "From a practical and prevention perspective, we still need to rely on people using valid methods of protection to avoid being infected or infecting."

New Mexican Health-care Program Successful At Reducing Crippling Health Care Costs

Seguro Popular, a Mexican health care program instituted in 2003, has already reduced crippling health care costs among poorer households, according to an evaluation conducted by researchers at Harvard University in collaboration with researchers in Mexico.

The study was designed and led by Gary King, David Florence Professor of Government and director of the Institute for Quantitative Social Science at Harvard. The results are published in the current issue of The Lancet.

"The success of Seguro Popular in reducing catastrophic health expenditures is remarkable," says King, "not least because governmental money spent on the poor in many countries rarely reaches the intended recipients."

King's study of about 500,000 people is the largest-ever randomized health policy experiment. It features innovative research designs and statistical methods he and his colleagues developed that increase what we learn from an evaluation while simultaneously saving a great deal of money. The design includes several failsafe components that preserve the experimental randomization even if politics or other problems intervene, including those which have ruined most previous large scale public policy evaluations. The approach is now being implemented or considered for evaluations of many other public policy programs around the world.

Passed in 2003, Seguro Popular was developed to provide health care to 50 million Mexicans who otherwise lack coverage. Voluntary enrollment in the program, at no cost to the poor, provides access to health clinics, drugs, regular and preventative medical care, and the money to pay for it all. The program's primary goal is the reduction of catastrophic health expenses, those exceeding one-third of a household's yearly disposable income.

About a half a million people in 118,569 households were included in this study, which was conducted over 10 months. In the treatment clusters, 44 percent of households reported participating in the program, compared to 7.3 percent in control communities, which was approximately as expected. Among participating households, those suffering catastrophic health expenses were reduced by almost 60 percent, contributing to a 30 percent reduction in catastrophic health expenses across treatment communities.

The evaluation also highlighted areas in which the program was ineffective. Contrary to prior non-randomized studies, the researchers found no increase in utilization of health services, although longer-term research may show an increase. Health outcomes will also take longer to show an effect.

Before the program was instituted, 174 communities were paired up based on having similar background variables, such as the health of the community, size, and the number of schools. Then one community within each pair was randomly chosen to receive treatment: Families were encouraged to enroll in Seguro Popular, health facilities were built or upgraded, and medical personnel, drugs, and other supplies were provided. In the other community within each pair, no changes were made.

"One advantage of this design is that if one of the communities was to drop out of the study, due to interventions by politicians or for other reasons, the paired community would be removed as well, and the balance between the treated and control groups would not be affected. In contrast, classical randomized experiments are destroyed when even one community is lost. The matched pair design also decreased the margin of error to as little as one-sixth of what it would be with traditional experimental methods," says King. "That's the equivalent of collecting many more respondents, or randomizing throughout many more communities, for the same cost."

Seguro Popular in Mexico covers about the same number of people as are uninsured in America. King points out that there may be lessons for other countries to learn in the success of Seguro Popular.

King's co-authors were Emmanuela Gakidou of the University of Washington; Kosuke Imai of Princeton University; Jason Lakin, Clayton Nall, and Nirmala Ravishankar of Harvard; Ryan Moore of Washington University in St. Louis; Manett Vargas of the Ministry of Health in Mexico; Martha María Téllez-Rojo and Juan Eugenio Hernández Ávila of the National Institute of Public Health in Mexico; Mauricio Hernández Ávila of the Ministry of Health in Mexico and the National Institute of Public Health in Mexico; and Héctor Hernández Llamas of Conestadistica. Gakidou, Imai, Lakin, Nall, Ravishankar, Moore, and Vargas are all King's current or former students and affiliates at the Harvard Institute for Quantitative Social Sciences.

The research was funded by the Mexican Ministry of Health, the National Institute of Public Health in Mexico, and the Harvard Institute for Quantitative Social Science.

Partner Behavior Better Predicts STD Risks

Risky behaviors such as not using condoms or having sex with multiple people put young adults at risk for contracting sexually transmitted diseases, but perhaps not as much as the characteristics of their sexual partners, University of Florida researchers say.

The findings, which UF and University of Pittsburgh researchers report in the April issue of Sexually Transmitted Diseases, could help health-care providers better screen patients for STD risks, said Stephanie A. S. Staras, Ph.D., a UF assistant professor of epidemiology and health policy research in the UF College of Medicine.

"If you are choosing high-risk partners, you are much more likely to have an STD, even when we account for your condom-use patterns," said Staras, the lead author of the study. "The theory is simple: You need to have sex with someone who has an STD to get an STD. Based on the prevalence of STDs in the United States, it seems like the public may not fully understand their risk."

The study examined the sexual activities, partner characteristics and STD diagnoses of 412 subjects between the ages of 15 and 24. Among the subjects whose partners were categorized as high-risk, half were diagnosed with an STD. By comparison, about 40 percent of the young adults whose own behaviors were labeled as high-risk were diagnosed with an STD.

According to the Centers for Disease Control and Prevention, about 19 million people in the United States contract STDs each year. About half of them are between the ages of 15 and 24.

Health-care providers often ask patients about their own sexual behaviors, but inquiring only about a person's own behaviors may cause some patients to slip through the cracks, Staras said. For example, some subjects in the study reported very low-risk behaviors but were having sex with very high-risk partners.

Adding a few simple questions about partner characteristics during STD screenings could help providers catch more patients who need to be tested and educated about condom use and other protective measures, Staras said.

"Partner selection is an area of STD prevention that could complement what we are already doing with promoting condom use, and could possibly really help people," Staras said. "If somehow we could convince individuals to incorporate this information in a meaningful way into their decision-making, then we could reduce STDs."

UF researchers measured five specific characteristics to gauge how risky certain partners were. These characteristics included whether the partner has a problem with marijuana or alcohol, was at least five years older or younger, had been in jail, had sex with other people in the past year or had an STD in the past year.

The researchers then created a composite, totaling up the number of negative partner characteristics for each subject and comparing them against the number of each person's own individual risky behaviors, which ranged from how often they used condoms to how many people they had sex with.

Overall, researchers found considering all of the partner characteristics together was the strongest predictor for STDs. Young adults whose partners had five or more risk characteristics were three times more likely to have an STD than those whose partners had no more than two characteristics.

Of these characteristics, the most telling were if a partner already had an STD and if a couple had an age difference of more than five years. Subjects whose partners were five years older or younger than them were more than twice as likely to be diagnosed with an STD than those whose partners were around the same age, the researchers found.

"It's all about the risk of the partner and sometimes we forget that," said Richard A. Crosby, Ph.D., the DDI endowed professor and chairman of the department of health behavior at the University of Kentucky and a co-director of the Rural Center for AIDS/STD Prevention.

But Crosby, who was not involved in the UF study, said it's also important for people to remember that the risks mentioned in the study are just generalizations, not set-in-stone giveaways for STDs.

"From a public health perspective, it's important to understand these findings," he said. "From a practical and prevention perspective, we still need to rely on people using valid methods of protection to avoid being infected or infecting."

Hispanics Appear To Face Poorer Quality Nursing Home Care

Nursing homes serving primarily Hispanic residents provided poorer quality care compared to facilities whose patients were mostly white, according to Brown University research. Details were published recently in the Journal of the American Medical Directors Association.

Researchers reached their conclusions after looking at the rate of bed sores at nursing homes with high concentrations of Hispanic patients, compared to others with low concentrations. Hispanics at nursing homes with a high rate of Hispanic residents were more likely to have bed sores, compared to Hispanics living in nursing homes with fewer Hispanic residents.

Michael Gerardo, adjunct assistant professor of community health at the Warren Alpert Medical School of Brown University, led the research. Two others served as co-authors — Joan Teno, M.D., professor of community health and medicine and an expert on end-of-life care, and Vincent Mor, chair of the Department of Community Health, whose work focuses on nursing home care among other areas.

Gerardo and the other professors said that more research is needed to determine the implications of their findings, directed specifically at the root cause for disparities between high-quality and low-quality nursing homes.

“A systemic evaluation of the difference in the process of care between high- and low-quality nursing homes is warranted in order to reduce nursing home disparities,” Gerardo said.

Their work comes less than two years after a landmark 2007 study, published in Health Affairs, that suggests blacks are more likely than whites to live in poor-quality nursing homes. That study found that the problem was worst in the Midwest, and that inequalities in care are closely correlated to racial segregation. Mor was lead author for that study.

For the study of Hispanics in nursing homes, the researchers looked at two data sources. One, the national repository of the Minimum Data Set, is a federally mandated report of health status, function and demographics on all nursing home residents. The other, which is known as the Oscar database system, collects information on patients and nursing homes, via the Centers for Medicaid and Medicare Services.

Residents were included if they were age 65 or older, living at free-standing nursing homes in California, New Mexico, Texas, Arizona or Colorado.

Funding from the National Institutes of Health, National Institute on Aging, A National Research Service Award Institutional Training Grant and the Commonwealth Fund helped support the study.

Hispanics Appear To Face Poorer Quality Nursing Home Care

Nursing homes serving primarily Hispanic residents provided poorer quality care compared to facilities whose patients were mostly white, according to Brown University research. Details were published recently in the Journal of the American Medical Directors Association.

Researchers reached their conclusions after looking at the rate of bed sores at nursing homes with high concentrations of Hispanic patients, compared to others with low concentrations. Hispanics at nursing homes with a high rate of Hispanic residents were more likely to have bed sores, compared to Hispanics living in nursing homes with fewer Hispanic residents.

Michael Gerardo, adjunct assistant professor of community health at the Warren Alpert Medical School of Brown University, led the research. Two others served as co-authors — Joan Teno, M.D., professor of community health and medicine and an expert on end-of-life care, and Vincent Mor, chair of the Department of Community Health, whose work focuses on nursing home care among other areas.

Gerardo and the other professors said that more research is needed to determine the implications of their findings, directed specifically at the root cause for disparities between high-quality and low-quality nursing homes.

“A systemic evaluation of the difference in the process of care between high- and low-quality nursing homes is warranted in order to reduce nursing home disparities,” Gerardo said.

Their work comes less than two years after a landmark 2007 study, published in Health Affairs, that suggests blacks are more likely than whites to live in poor-quality nursing homes. That study found that the problem was worst in the Midwest, and that inequalities in care are closely correlated to racial segregation. Mor was lead author for that study.

For the study of Hispanics in nursing homes, the researchers looked at two data sources. One, the national repository of the Minimum Data Set, is a federally mandated report of health status, function and demographics on all nursing home residents. The other, which is known as the Oscar database system, collects information on patients and nursing homes, via the Centers for Medicaid and Medicare Services.

Residents were included if they were age 65 or older, living at free-standing nursing homes in California, New Mexico, Texas, Arizona or Colorado.

Funding from the National Institutes of Health, National Institute on Aging, A National Research Service Award Institutional Training Grant and the Commonwealth Fund helped support the study.

Diabetes Insipidus

What is diabetes insipidus?

Diabetes insipidus (DI) is a rare disease that causes frequent urination. The large volume of urine is diluted, mostly water. To make up for lost water, a person with DI may feel the need to drink large amounts and is likely to urinate frequently, even at night, which can disrupt sleep and, on occasion, cause bedwetting. Because of the excretion of abnormally large volumes of dilute urine, people with DI may quickly become dehydrated if they do not drink enough water. Children with DI may be irritable or listless and may have fever, vomiting, or diarrhea. Milder forms of DI can be managed by drinking enough water, usually between 2 and 2.5 liters a day. DI severe enough to endanger a person’s health is rare.

[Top]

What is the difference between diabetes insipidus and diabetes mellitus?

DI should not be confused with diabetes mellitus (DM), which results from insulin deficiency or resistance leading to high blood glucose, also called blood sugar. DI and DM are unrelated, although they can have similar signs and symptoms, like excessive thirst and excessive urination.

DM is far more common than DI and receives more news coverage. DM has two main forms, type 1 diabetes and type 2 diabetes. DI is a different form of illness altogether.

[Top]

How is fluid in the body normally regulated?

The body has a complex system for balancing the volume and composition of body fluids. The kidneys remove extra body fluids from the bloodstream. These fluids are stored in the bladder as urine. If the fluid regulation system is working properly, the kidneys make less urine to conserve fluid when water intake is decreased or water is lost, for example, through sweating or diarrhea. The kidneys also make less urine at night when the body’s metabolic processes are slower.

The hypothalamus makes antidiuretic hormone (ADH), which directs the kidneys to make less urine.

To keep the volume and composition of body fluids balanced, the rate of fluid intake is governed by thirst, and the rate of excretion is governed by the production of antidiuretic hormone (ADH), also called vasopressin. This hormone is made in the hypothalamus, a small gland located in the brain. ADH is stored in the nearby pituitary gland and released into the bloodstream when necessary. When ADH reaches the kidneys, it directs them to concentrate the urine by reabsorbing some of the filtered water to the bloodstream and therefore make less urine. DI occurs when this precise system for regulating the kidneys’ handling of fluids is disrupted.

[Top]

What are the types of diabetes insipidus?

Central DI

The most common form of serious DI, central DI, results from damage to the pituitary gland, which disrupts the normal storage and release of ADH. Damage to the pituitary gland can be caused by different diseases as well as by head injuries, neurosurgery, or genetic disorders. To treat the ADH deficiency that results from any kind of damage to the hypothalamus or pituitary, a synthetic hormone called desmopressin can be taken by an injection, a nasal spray, or a pill. While taking desmopressin, a person should drink fluids only when thirsty and not at other times. The drug prevents water excretion, and water can build up now that the kidneys are making less urine and are less responsive to changes in body fluids.

Nephrogenic DI

Nephrogenic DI results when the kidneys are unable to respond to ADH. The kidneys’ ability to respond to ADH can be impaired by drugs—like lithium, for example—and by chronic disorders including polycystic kidney disease, sickle cell disease, kidney failure, partial blockage of the ureters, and inherited genetic disorders. Sometimes the cause of nephrogenic DI is never discovered.

Desmopressin will not work for this form of DI. Instead, a person with nephrogenic DI may be given hydrochlorothiazide (HCTZ) or indomethacin. HCTZ is sometimes combined with another drug called amiloride. The combination of HCTZ and amiloride is sold under the brand name Moduretic. Again, with this combination of drugs, one should drink fluids only when thirsty and not at other times.

Dipsogenic DI

Dipsogenic DI is caused by a defect in or damage to the thirst mechanism, which is located in the hypothalamus. This defect results in an abnormal increase in thirst and fluid intake that suppresses ADH secretion and increases urine output. Desmopressin or other drugs should not be used to treat dipsogenic DI because they may decrease urine output but not thirst and fluid intake. This fluid overload can lead to water intoxication, a condition that lowers the concentration of sodium in the blood and can seriously damage the brain. Scientists have not yet found an effective treatment for dipsogenic DI.

Gestational DI

Gestational DI occurs only during pregnancy and results when an enzyme made by the placenta destroys ADH in the mother. The placenta is the system of blood vessels and other tissue that develops with the fetus. The placenta allows exchange of nutrients and waste products between mother and fetus.

Most cases of gestational DI can be treated with desmopressin. In rare cases, however, an abnormality in the thirst mechanism causes gestational DI, and desmopressin should not be used.

Diabetes Insipidus

What is diabetes insipidus?

Diabetes insipidus (DI) is a rare disease that causes frequent urination. The large volume of urine is diluted, mostly water. To make up for lost water, a person with DI may feel the need to drink large amounts and is likely to urinate frequently, even at night, which can disrupt sleep and, on occasion, cause bedwetting. Because of the excretion of abnormally large volumes of dilute urine, people with DI may quickly become dehydrated if they do not drink enough water. Children with DI may be irritable or listless and may have fever, vomiting, or diarrhea. Milder forms of DI can be managed by drinking enough water, usually between 2 and 2.5 liters a day. DI severe enough to endanger a person’s health is rare.

[Top]

What is the difference between diabetes insipidus and diabetes mellitus?

DI should not be confused with diabetes mellitus (DM), which results from insulin deficiency or resistance leading to high blood glucose, also called blood sugar. DI and DM are unrelated, although they can have similar signs and symptoms, like excessive thirst and excessive urination.

DM is far more common than DI and receives more news coverage. DM has two main forms, type 1 diabetes and type 2 diabetes. DI is a different form of illness altogether.

[Top]

How is fluid in the body normally regulated?

The body has a complex system for balancing the volume and composition of body fluids. The kidneys remove extra body fluids from the bloodstream. These fluids are stored in the bladder as urine. If the fluid regulation system is working properly, the kidneys make less urine to conserve fluid when water intake is decreased or water is lost, for example, through sweating or diarrhea. The kidneys also make less urine at night when the body’s metabolic processes are slower.

The hypothalamus makes antidiuretic hormone (ADH), which directs the kidneys to make less urine.

To keep the volume and composition of body fluids balanced, the rate of fluid intake is governed by thirst, and the rate of excretion is governed by the production of antidiuretic hormone (ADH), also called vasopressin. This hormone is made in the hypothalamus, a small gland located in the brain. ADH is stored in the nearby pituitary gland and released into the bloodstream when necessary. When ADH reaches the kidneys, it directs them to concentrate the urine by reabsorbing some of the filtered water to the bloodstream and therefore make less urine. DI occurs when this precise system for regulating the kidneys’ handling of fluids is disrupted.

[Top]

What are the types of diabetes insipidus?

Central DI

The most common form of serious DI, central DI, results from damage to the pituitary gland, which disrupts the normal storage and release of ADH. Damage to the pituitary gland can be caused by different diseases as well as by head injuries, neurosurgery, or genetic disorders. To treat the ADH deficiency that results from any kind of damage to the hypothalamus or pituitary, a synthetic hormone called desmopressin can be taken by an injection, a nasal spray, or a pill. While taking desmopressin, a person should drink fluids only when thirsty and not at other times. The drug prevents water excretion, and water can build up now that the kidneys are making less urine and are less responsive to changes in body fluids.

Nephrogenic DI

Nephrogenic DI results when the kidneys are unable to respond to ADH. The kidneys’ ability to respond to ADH can be impaired by drugs—like lithium, for example—and by chronic disorders including polycystic kidney disease, sickle cell disease, kidney failure, partial blockage of the ureters, and inherited genetic disorders. Sometimes the cause of nephrogenic DI is never discovered.

Desmopressin will not work for this form of DI. Instead, a person with nephrogenic DI may be given hydrochlorothiazide (HCTZ) or indomethacin. HCTZ is sometimes combined with another drug called amiloride. The combination of HCTZ and amiloride is sold under the brand name Moduretic. Again, with this combination of drugs, one should drink fluids only when thirsty and not at other times.

Dipsogenic DI

Dipsogenic DI is caused by a defect in or damage to the thirst mechanism, which is located in the hypothalamus. This defect results in an abnormal increase in thirst and fluid intake that suppresses ADH secretion and increases urine output. Desmopressin or other drugs should not be used to treat dipsogenic DI because they may decrease urine output but not thirst and fluid intake. This fluid overload can lead to water intoxication, a condition that lowers the concentration of sodium in the blood and can seriously damage the brain. Scientists have not yet found an effective treatment for dipsogenic DI.

Gestational DI

Gestational DI occurs only during pregnancy and results when an enzyme made by the placenta destroys ADH in the mother. The placenta is the system of blood vessels and other tissue that develops with the fetus. The placenta allows exchange of nutrients and waste products between mother and fetus.

Most cases of gestational DI can be treated with desmopressin. In rare cases, however, an abnormality in the thirst mechanism causes gestational DI, and desmopressin should not be used.

Kidney Disease of Diabetes

The Burden of Kidney Failure

Each year in the United States, more than 100,000 people are diagnosed with kidney failure, a serious condition in which the kidneys fail to rid the body of wastes.¹ Kidney failure is the final stage of chronic kidney disease (CKD).

Diabetes is the most common cause of kidney failure, accounting for nearly 44 percent of new cases.¹ Even when diabetes is controlled, the disease can lead to CKD and kidney failure. Most people with diabetes do not develop CKD that is severe enough to progress to kidney failure. Nearly 24 million people in the United States have diabetes, ² and nearly 180,000 people are living with kidney failure as a result of diabetes.¹

People with kidney failure undergo either dialysis, an artificial blood-cleaning process, or transplantation to receive a healthy kidney from a donor. Most U.S. citizens who develop kidney failure are eligible for federally funded care. In 2005, care for patients with kidney failure cost the United States nearly $32 billion.¹

Source: United States Renal Data System. USRDS 2007 Annual Data Report.

African Americans, American Indians, and Hispanics/Latinos develop diabetes, CKD, and kidney failure at rates higher than Caucasians. Scientists have not been able to explain these higher rates. Nor can they explain fully the interplay of factors leading to kidney disease of diabetes—factors including heredity, diet, and other medical conditions, such as high blood pressure. They have found that high blood pressure and high levels of blood glucose increase the risk that a person with diabetes will progress to kidney failure.

¹United States Renal Data System. USRDS 2007 Annual Data Report. Bethesda, MD: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, U.S. Department of Health and Human Services; 2007.

²National Institute of Diabetes and Digestive and Kidney Diseases. National Diabetes Statistics, 2007. Bethesda, MD: National Institutes of Health, U.S. Department of Health and Human Services, 2008.

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The Course of Kidney Disease

Diabetic kidney disease takes many years to develop. In some people, the filtering function of the kidneys is actually higher than normal in the first few years of their diabetes.

Over several years, people who are developing kidney disease will have small amounts of the blood protein albumin begin to leak into their urine. This first stage of CKD is called microalbuminuria. The kidney’s filtration function usually remains normal during this period.

As the disease progresses, more albumin leaks into the urine. This stage may be called macroalbuminuria or proteinuria. As the amount of albumin in the urine increases, the kidneys’ filtering function usually begins to drop. The body retains various wastes as filtration falls. As kidney damage develops, blood pressure often rises as well.

Overall, kidney damage rarely occurs in the first 10 years of diabetes, and usually 15 to 25 years will pass before kidney failure occurs. For people who live with diabetes for more than 25 years without any signs of kidney failure, the risk of ever developing it decreases.

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Diagnosis of CKD

People with diabetes should be screened regularly for kidney disease. The two key markers for kidney disease are eGFR and urine albumin.

• eGFR. eGFR stands for estimated glomerular filtration rate. Each kidney contains about 1 million tiny filters made up of blood vessels. These filters are called glomeruli. Kidney function can be checked by estimating how much blood the glomeruli filter in a minute. The calculation of eGFR is based on the amount of creatinine, a waste product, found in a blood sample. As the level of creatinine goes up, the eGFR goes down.

  Kidney disease is present when eGFR is less than 60 milliliters per minute.

  The American Diabetes Association (ADA) and the National Institutes of Health (NIH) recommend that eGFR be calculated from serum creatinine at least once a year in all people with diabetes.

• Urine albumin. Urine albumin is measured by comparing the amount of albumin to the amount of creatinine in a single urine sample. When the kidneys are healthy, the urine will contain large amounts of creatinine but almost no albumin. Even a small increase in the ratio of albumin to creatinine is a sign of kidney damage.

  Kidney disease is present when urine contains more than 30 milligrams of albumin per gram of creatinine, with or without decreased eGFR.

  The ADA and the NIH recommend annual assessment of urine albumin excretion to assess kidney damage in all people with type 2 diabetes and people who have had type 1 diabetes for 5 years or more.

Kidney Disease of Diabetes

The Burden of Kidney Failure

Each year in the United States, more than 100,000 people are diagnosed with kidney failure, a serious condition in which the kidneys fail to rid the body of wastes.¹ Kidney failure is the final stage of chronic kidney disease (CKD).

Diabetes is the most common cause of kidney failure, accounting for nearly 44 percent of new cases.¹ Even when diabetes is controlled, the disease can lead to CKD and kidney failure. Most people with diabetes do not develop CKD that is severe enough to progress to kidney failure. Nearly 24 million people in the United States have diabetes, ² and nearly 180,000 people are living with kidney failure as a result of diabetes.¹

People with kidney failure undergo either dialysis, an artificial blood-cleaning process, or transplantation to receive a healthy kidney from a donor. Most U.S. citizens who develop kidney failure are eligible for federally funded care. In 2005, care for patients with kidney failure cost the United States nearly $32 billion.¹

Source: United States Renal Data System. USRDS 2007 Annual Data Report.

African Americans, American Indians, and Hispanics/Latinos develop diabetes, CKD, and kidney failure at rates higher than Caucasians. Scientists have not been able to explain these higher rates. Nor can they explain fully the interplay of factors leading to kidney disease of diabetes—factors including heredity, diet, and other medical conditions, such as high blood pressure. They have found that high blood pressure and high levels of blood glucose increase the risk that a person with diabetes will progress to kidney failure.

¹United States Renal Data System. USRDS 2007 Annual Data Report. Bethesda, MD: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, U.S. Department of Health and Human Services; 2007.

²National Institute of Diabetes and Digestive and Kidney Diseases. National Diabetes Statistics, 2007. Bethesda, MD: National Institutes of Health, U.S. Department of Health and Human Services, 2008.

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The Course of Kidney Disease

Diabetic kidney disease takes many years to develop. In some people, the filtering function of the kidneys is actually higher than normal in the first few years of their diabetes.

Over several years, people who are developing kidney disease will have small amounts of the blood protein albumin begin to leak into their urine. This first stage of CKD is called microalbuminuria. The kidney’s filtration function usually remains normal during this period.

As the disease progresses, more albumin leaks into the urine. This stage may be called macroalbuminuria or proteinuria. As the amount of albumin in the urine increases, the kidneys’ filtering function usually begins to drop. The body retains various wastes as filtration falls. As kidney damage develops, blood pressure often rises as well.

Overall, kidney damage rarely occurs in the first 10 years of diabetes, and usually 15 to 25 years will pass before kidney failure occurs. For people who live with diabetes for more than 25 years without any signs of kidney failure, the risk of ever developing it decreases.

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Diagnosis of CKD

People with diabetes should be screened regularly for kidney disease. The two key markers for kidney disease are eGFR and urine albumin.

• eGFR. eGFR stands for estimated glomerular filtration rate. Each kidney contains about 1 million tiny filters made up of blood vessels. These filters are called glomeruli. Kidney function can be checked by estimating how much blood the glomeruli filter in a minute. The calculation of eGFR is based on the amount of creatinine, a waste product, found in a blood sample. As the level of creatinine goes up, the eGFR goes down.

  Kidney disease is present when eGFR is less than 60 milliliters per minute.

  The American Diabetes Association (ADA) and the National Institutes of Health (NIH) recommend that eGFR be calculated from serum creatinine at least once a year in all people with diabetes.

• Urine albumin. Urine albumin is measured by comparing the amount of albumin to the amount of creatinine in a single urine sample. When the kidneys are healthy, the urine will contain large amounts of creatinine but almost no albumin. Even a small increase in the ratio of albumin to creatinine is a sign of kidney damage.

  Kidney disease is present when urine contains more than 30 milligrams of albumin per gram of creatinine, with or without decreased eGFR.

  The ADA and the NIH recommend annual assessment of urine albumin excretion to assess kidney damage in all people with type 2 diabetes and people who have had type 1 diabetes for 5 years or more.

Chronic Kidney Disease: A Family Affair

Chronic kidney disease (CKD) is the permanent loss of kidney function. CKD may be the result of physical injury or a disease that damages the kidneys, such as diabetes or high blood pressure. When the kidneys are damaged, they do not remove wastes and extra water from the blood as well as they should.

CKD is a family affair because you may be at risk if you have a blood relative with kidney failure.

CKD is a silent condition. In the early stages, you will not notice any symptoms. CKD often develops so slowly that many people don't realize they're sick until the disease is advanced and they are rushed to the hospital for life-saving dialysis.

A Growing Problem
CKD is a growing problem in the United States. Between 1990 and 2000, the number of people with kidney failure requiring dialysis or transplantation virtually doubled to 380,000. If this trend continues, the number of people with kidney failure will approach 700,000 by 2010. The annual cost of treating kidney failure in the United States has already topped $20 billion.

Kidney failure is only a part of the picture. Experts estimate that 20 million Americans have significantly reduced kidney function, and even a small loss of kidney function can double a person's risk of developing cardiovascular disease. Many of these people will experience heart attacks or strokes before they become aware of their kidney disease. So identifying and treating CKD early can help prevent heart problems as well as postpone kidney failure.

Between 1990 and 2000, the number of people with kidney failure requiring dialysis or transplantation more than doubled.

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Who is at risk?

Risk factors are conditions that make you more likely to develop a disease. The leading risk factors for CKD are

• diabetes



• high blood pressure



• family history of kidney failure

Having diabetes increases your risk of developing CKD. In fact, diabetes is the leading cause of kidney failure. High blood pressure is the second leading cause.

CKD runs in families, so you may have an increased risk if your mother, father, sister, or brother has kidney failure.

Some racial groups are also at increased risk for CKD.

• African Americans are nearly four times as likely to develop kidney failure as white Americans.



• American Indians have nearly three times the risk compared to whites.



• Hispanic Americans have nearly twice the risk of non-Hispanic whites.

Screening for kidney disease includes simple blood and urine tests.

If you have diabetes or high blood pressure, or a close family member with kidney failure, you should get checked for kidney disease, especially if you're a member of one of the racial or ethnic groups at higher risk for CKD.

Chronic Kidney Disease: A Family Affair

Chronic kidney disease (CKD) is the permanent loss of kidney function. CKD may be the result of physical injury or a disease that damages the kidneys, such as diabetes or high blood pressure. When the kidneys are damaged, they do not remove wastes and extra water from the blood as well as they should.

CKD is a family affair because you may be at risk if you have a blood relative with kidney failure.

CKD is a silent condition. In the early stages, you will not notice any symptoms. CKD often develops so slowly that many people don't realize they're sick until the disease is advanced and they are rushed to the hospital for life-saving dialysis.

A Growing Problem
CKD is a growing problem in the United States. Between 1990 and 2000, the number of people with kidney failure requiring dialysis or transplantation virtually doubled to 380,000. If this trend continues, the number of people with kidney failure will approach 700,000 by 2010. The annual cost of treating kidney failure in the United States has already topped $20 billion.

Kidney failure is only a part of the picture. Experts estimate that 20 million Americans have significantly reduced kidney function, and even a small loss of kidney function can double a person's risk of developing cardiovascular disease. Many of these people will experience heart attacks or strokes before they become aware of their kidney disease. So identifying and treating CKD early can help prevent heart problems as well as postpone kidney failure.

Between 1990 and 2000, the number of people with kidney failure requiring dialysis or transplantation more than doubled.

[Top]

Who is at risk?

Risk factors are conditions that make you more likely to develop a disease. The leading risk factors for CKD are

• diabetes



• high blood pressure



• family history of kidney failure

Having diabetes increases your risk of developing CKD. In fact, diabetes is the leading cause of kidney failure. High blood pressure is the second leading cause.

CKD runs in families, so you may have an increased risk if your mother, father, sister, or brother has kidney failure.

Some racial groups are also at increased risk for CKD.

• African Americans are nearly four times as likely to develop kidney failure as white Americans.



• American Indians have nearly three times the risk compared to whites.



• Hispanic Americans have nearly twice the risk of non-Hispanic whites.

Screening for kidney disease includes simple blood and urine tests.

If you have diabetes or high blood pressure, or a close family member with kidney failure, you should get checked for kidney disease, especially if you're a member of one of the racial or ethnic groups at higher risk for CKD.

High Blood Pressure and Kidney Disease

What is high blood pressure?

Blood pressure measures the force of blood against the walls of the blood vessels. Extra fluid in the body increases the amount of fluid in blood vessels and makes blood pressure higher. Narrow, stiff, or clogged blood vessels also raise blood pressure.

[d]
Hypertension can result from too much fluid in normal blood vessels or from normal fluid in narrow, stiff, or clogged blood vessels.

People with high blood pressure should see their doctor regularly.

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How does high blood pressure hurt the kidneys?

High blood pressure makes the heart work harder and, over time, can damage blood vessels throughout the body. If the blood vessels in the kidneys are damaged, they may stop removing wastes and extra fluid from the body. The extra fluid in the blood vessels may then raise blood pressure even more. It’s a dangerous cycle.

High blood pressure is one of the leading causes of kidney failure, also called end-stage renal disease (ESRD). People with kidney failure must either receive a kidney transplant or have regular blood-cleansing treatments called dialysis. Every year, high blood pressure causes more than 25,000 new cases of kidney failure in the United States.¹

¹United States Renal Data System. USRDS 2007 Annual Data Report. Bethesda, MD: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, U.S. Department of Health and Human Services; 2007.

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What are the signs and symptoms of high blood pressure?

Most people with high blood pressure have no symptoms. The only way to know whether a person’s blood pressure is high is to have a health professional measure it with a blood pressure cuff. The result is expressed as two numbers. The top number, called the systolic pressure, represents the pressure when the heart is beating. The bottom number, called the diastolic pressure, shows the pressure when the heart is resting between beats. A person’s blood pressure is considered normal if it stays at or below 120/80, which is commonly stated as “120 over 80.” People with a systolic blood pressure of 120 to 139 or a diastolic blood pressure of 80 to 89 are considered prehypertensive and should adopt lifestyle changes to lower their blood pressure and prevent heart and blood vessel diseases. A person whose systolic blood pressure is consistently 140 or higher or whose diastolic pressure is 90 or higher is considered to have high blood pressure and should talk with a doctor about the best ways to lower it.

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What are the signs and symptoms of chronic kidney disease (CKD)?

Early kidney disease is a silent problem, like high blood pressure, and does not have any symptoms. People may have CKD but not know it because they do not feel sick. A person’s glomerular filtration rate (GFR) is a measure of how well the kidneys are filtering wastes from the blood. GFR is estimated from a routine measurement of creatinine in the blood. The result is called the estimated GFR (eGFR).

Creatinine is a waste product formed by the normal breakdown of muscle cells. Healthy kidneys take creatinine out of the blood and put it into the urine to leave the body. When the kidneys are not working well, creatinine builds up in the blood.

An eGFR with a value below 60 milliliters per minute (mL/min) suggests some kidney damage has occurred. The score means that a person’s kidneys are not working at full strength.

Another sign of CKD is proteinuria, or protein in the urine. Healthy kidneys take wastes out of the blood but leave protein. Impaired kidneys may fail to separate a blood protein called albumin from the wastes. At first, only small amounts of albumin may leak into the urine, a condition known as microalbuminuria, a sign of failing kidney function. As kidney function worsens, the amount of albumin and other proteins in the urine increases, and the condition is called proteinuria. CKD is present when more than 30 milligrams of albumin per gram of creatinine is excreted in urine, with or without decreased eGFR.

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How can kidney damage from high blood pressure be prevented?

The National Heart, Lung, and Blood Institute (NHLBI), one of the National Institutes of Health (NIH), recommends that people with CKD use whatever therapy is necessary, including lifestyle changes and medicines, to keep their blood pressure below 130/80.

High Blood Pressure and Kidney Disease

What is high blood pressure?

Blood pressure measures the force of blood against the walls of the blood vessels. Extra fluid in the body increases the amount of fluid in blood vessels and makes blood pressure higher. Narrow, stiff, or clogged blood vessels also raise blood pressure.

[d]
Hypertension can result from too much fluid in normal blood vessels or from normal fluid in narrow, stiff, or clogged blood vessels.

People with high blood pressure should see their doctor regularly.

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How does high blood pressure hurt the kidneys?

High blood pressure makes the heart work harder and, over time, can damage blood vessels throughout the body. If the blood vessels in the kidneys are damaged, they may stop removing wastes and extra fluid from the body. The extra fluid in the blood vessels may then raise blood pressure even more. It’s a dangerous cycle.

High blood pressure is one of the leading causes of kidney failure, also called end-stage renal disease (ESRD). People with kidney failure must either receive a kidney transplant or have regular blood-cleansing treatments called dialysis. Every year, high blood pressure causes more than 25,000 new cases of kidney failure in the United States.¹

¹United States Renal Data System. USRDS 2007 Annual Data Report. Bethesda, MD: National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, U.S. Department of Health and Human Services; 2007.

[Top]

What are the signs and symptoms of high blood pressure?

Most people with high blood pressure have no symptoms. The only way to know whether a person’s blood pressure is high is to have a health professional measure it with a blood pressure cuff. The result is expressed as two numbers. The top number, called the systolic pressure, represents the pressure when the heart is beating. The bottom number, called the diastolic pressure, shows the pressure when the heart is resting between beats. A person’s blood pressure is considered normal if it stays at or below 120/80, which is commonly stated as “120 over 80.” People with a systolic blood pressure of 120 to 139 or a diastolic blood pressure of 80 to 89 are considered prehypertensive and should adopt lifestyle changes to lower their blood pressure and prevent heart and blood vessel diseases. A person whose systolic blood pressure is consistently 140 or higher or whose diastolic pressure is 90 or higher is considered to have high blood pressure and should talk with a doctor about the best ways to lower it.

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What are the signs and symptoms of chronic kidney disease (CKD)?

Early kidney disease is a silent problem, like high blood pressure, and does not have any symptoms. People may have CKD but not know it because they do not feel sick. A person’s glomerular filtration rate (GFR) is a measure of how well the kidneys are filtering wastes from the blood. GFR is estimated from a routine measurement of creatinine in the blood. The result is called the estimated GFR (eGFR).

Creatinine is a waste product formed by the normal breakdown of muscle cells. Healthy kidneys take creatinine out of the blood and put it into the urine to leave the body. When the kidneys are not working well, creatinine builds up in the blood.

An eGFR with a value below 60 milliliters per minute (mL/min) suggests some kidney damage has occurred. The score means that a person’s kidneys are not working at full strength.

Another sign of CKD is proteinuria, or protein in the urine. Healthy kidneys take wastes out of the blood but leave protein. Impaired kidneys may fail to separate a blood protein called albumin from the wastes. At first, only small amounts of albumin may leak into the urine, a condition known as microalbuminuria, a sign of failing kidney function. As kidney function worsens, the amount of albumin and other proteins in the urine increases, and the condition is called proteinuria. CKD is present when more than 30 milligrams of albumin per gram of creatinine is excreted in urine, with or without decreased eGFR.

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How can kidney damage from high blood pressure be prevented?

The National Heart, Lung, and Blood Institute (NHLBI), one of the National Institutes of Health (NIH), recommends that people with CKD use whatever therapy is necessary, including lifestyle changes and medicines, to keep their blood pressure below 130/80.

Kidney Biopsy

What is a kidney biopsy?

A biopsy is a diagnostic test that involves collecting small pieces of tissue, usually through a needle, for examination with a microscope. A kidney biopsy can help in forming a diagnosis and in choosing the best course of treatment. A kidney biopsy may be recommended for any of the following conditions:

• hematuria, which is blood in the urine
• proteinuria, which is excessive protein in the urine
• impaired kidney function, which causes excessive waste products in the blood

A pathologist will look at the kidney tissue samples to check for unusual deposits, scarring, or infecting organisms that would explain a person’s condition. The doctor may find a condition that can be treated and cured. If a person has progressive kidney failure, the biopsy may show how quickly the disease is advancing. A biopsy can also help explain why a transplanted kidney is not working properly.

Patients should talk with their doctors about what information might be learned from the biopsy and the risks involved so the patients can help make a decision about whether a biopsy is worthwhile.

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What are the preparations for a kidney biopsy?

Patients must sign a consent form saying they understand the risks involved in this procedure. The risks are slight, but patients should discuss these risks in detail with their doctors before signing the form.

Doctors should be aware of all the medicines a patient takes and any drug allergies that patient might have. The patient should avoid aspirin and other blood-thinning medicines for 1 to 2 weeks before the procedure. Some doctors advise their patients to avoid food and fluids before the test, while others tell patients to eat a light meal. Shortly before the biopsy, blood and urine samples are taken to make sure the patient doesn’t have a condition that would make doing a biopsy risky.

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What are the procedures for a kidney biopsy?

Kidney biopsies are usually done in a hospital. The patient is fully awake with light sedation. A local anesthetic is given before the needle is inserted.

Patients lie on their stomachs to position the kidneys near the surface of their backs. Patients who have a transplanted kidney lie on their backs. The doctor marks the entry site, cleans the area, and injects a local painkiller. For a biopsy using a needle inserted through the skin, the doctor uses a locating needle and x-ray or ultrasound equipment to find the kidney and then a collecting needle to gather the tissue. Patients are asked to hold their breath as the doctor uses a spring-loaded instrument to insert the biopsy needle and collect the tissue, usually for about 30 seconds or a little longer for each insertion. The spring-loaded instrument makes a sharp clicking noise that can be startling to patients. The doctor may need to insert the needle three or four times to collect the needed samples.

The kidneys filter wastes and extra fluid from the blood and direct them to the bladder as urine.

The entire procedure usually takes about an hour, including time to locate the kidney, clean the biopsy site, inject the local painkiller, and collect the tissue samples.

Patients who are prone to bleeding problems should not have a biopsy through the skin. These patients may still undergo a kidney biopsy through an open operation in which the surgeon makes an incision and can see the kidney to collect tissue samples.

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What happens after a kidney biopsy?

After the test, patients lie on their backs in the hospital for a few hours. Patients who have a transplanted kidney lie on their stomachs. During this time, the staff will monitor blood pressure and pulse and take blood samples to assess for blood loss. On rare occasions when bleeding does not stop on its own, a transfusion may be necessary to replace lost blood. Most patients leave the hospital the same day. Patients may notice some blood in their urine for 24 hours after the test.

A rare complication is infection from the biopsy.

Patients should tell their doctors or nurses if they have any of these problems:

• bloody urine more than 24 hours after the test
• inability to urinate
• fever
• worsening pain in the biopsy site
• faintness or dizziness

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How are kidney biopsy results reported?

After the biopsy, the doctor will inspect the tissue samples in the laboratory using one or more microscopes, perhaps using dyes to identify different substances that may be settled in the tissue. Electron microscopes may be used to see small details. Getting the complete biopsy results usually takes a few days. In urgent cases, a preliminary report may be given within a few hours.

Kidney Biopsy

What is a kidney biopsy?

A biopsy is a diagnostic test that involves collecting small pieces of tissue, usually through a needle, for examination with a microscope. A kidney biopsy can help in forming a diagnosis and in choosing the best course of treatment. A kidney biopsy may be recommended for any of the following conditions:

• hematuria, which is blood in the urine
• proteinuria, which is excessive protein in the urine
• impaired kidney function, which causes excessive waste products in the blood

A pathologist will look at the kidney tissue samples to check for unusual deposits, scarring, or infecting organisms that would explain a person’s condition. The doctor may find a condition that can be treated and cured. If a person has progressive kidney failure, the biopsy may show how quickly the disease is advancing. A biopsy can also help explain why a transplanted kidney is not working properly.

Patients should talk with their doctors about what information might be learned from the biopsy and the risks involved so the patients can help make a decision about whether a biopsy is worthwhile.

[Top]

What are the preparations for a kidney biopsy?

Patients must sign a consent form saying they understand the risks involved in this procedure. The risks are slight, but patients should discuss these risks in detail with their doctors before signing the form.

Doctors should be aware of all the medicines a patient takes and any drug allergies that patient might have. The patient should avoid aspirin and other blood-thinning medicines for 1 to 2 weeks before the procedure. Some doctors advise their patients to avoid food and fluids before the test, while others tell patients to eat a light meal. Shortly before the biopsy, blood and urine samples are taken to make sure the patient doesn’t have a condition that would make doing a biopsy risky.

[Top]

What are the procedures for a kidney biopsy?

Kidney biopsies are usually done in a hospital. The patient is fully awake with light sedation. A local anesthetic is given before the needle is inserted.

Patients lie on their stomachs to position the kidneys near the surface of their backs. Patients who have a transplanted kidney lie on their backs. The doctor marks the entry site, cleans the area, and injects a local painkiller. For a biopsy using a needle inserted through the skin, the doctor uses a locating needle and x-ray or ultrasound equipment to find the kidney and then a collecting needle to gather the tissue. Patients are asked to hold their breath as the doctor uses a spring-loaded instrument to insert the biopsy needle and collect the tissue, usually for about 30 seconds or a little longer for each insertion. The spring-loaded instrument makes a sharp clicking noise that can be startling to patients. The doctor may need to insert the needle three or four times to collect the needed samples.

The kidneys filter wastes and extra fluid from the blood and direct them to the bladder as urine.

The entire procedure usually takes about an hour, including time to locate the kidney, clean the biopsy site, inject the local painkiller, and collect the tissue samples.

Patients who are prone to bleeding problems should not have a biopsy through the skin. These patients may still undergo a kidney biopsy through an open operation in which the surgeon makes an incision and can see the kidney to collect tissue samples.

[Top]

What happens after a kidney biopsy?

After the test, patients lie on their backs in the hospital for a few hours. Patients who have a transplanted kidney lie on their stomachs. During this time, the staff will monitor blood pressure and pulse and take blood samples to assess for blood loss. On rare occasions when bleeding does not stop on its own, a transfusion may be necessary to replace lost blood. Most patients leave the hospital the same day. Patients may notice some blood in their urine for 24 hours after the test.

A rare complication is infection from the biopsy.

Patients should tell their doctors or nurses if they have any of these problems:

• bloody urine more than 24 hours after the test
• inability to urinate
• fever
• worsening pain in the biopsy site
• faintness or dizziness

[Top]

How are kidney biopsy results reported?

After the biopsy, the doctor will inspect the tissue samples in the laboratory using one or more microscopes, perhaps using dyes to identify different substances that may be settled in the tissue. Electron microscopes may be used to see small details. Getting the complete biopsy results usually takes a few days. In urgent cases, a preliminary report may be given within a few hours.

Anemia in Kidney Disease and Dialysis

What is anemia?

A person whose blood is low in red blood cells has anemia. Red blood cells carry oxygen (O₂) to tissues and organs throughout the body and enable them to use the energy from food. Without oxygen, these tissues and organs—particularly the heart and brain—may not do their jobs as well as they should. For this reason, a person who has anemia may tire easily and look pale. Anemia may also contribute to heart problems.

Anemia is common in people with kidney disease. Healthy kidneys produce a hormone called erythropoietin, or EPO, which stimulates the bone marrow to produce the proper number of red blood cells needed to carry oxygen to vital organs. Diseased kidneys, however, often don’t make enough EPO. As a result, the bone marrow makes fewer red blood cells. Other common causes of anemia include blood loss from hemodialysis and low levels of iron and folic acid. These nutrients from food help young red blood cells make hemoglobin, their main oxygen-carrying protein.

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Healthy kidneys produce a hormone called erythropoietin, or EPO, which stimulates the bone marrow to make red blood cells needed to carry oxygen throughout the body. Diseased kidneys don’t make enough EPO, and bone marrow then makes fewer red blood cells.

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What are the laboratory tests for anemia?

A complete blood count (CBC), a laboratory test performed on a sample of blood, includes a determination of a person’s hematocrit, the percentage of the blood that consists of red blood cells. The CBC also measures the amount of hemoglobin in the blood. The range of normal hematocrit and hemoglobin in women who have a period is slightly lower than for healthy men and healthy women who have stopped having periods (postmenopausal). The hemoglobin is usually about one-third the value of the hematocrit.

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When does anemia begin?

Anemia may begin to develop in the early stages of kidney disease, when you still have 20 percent to 50 percent of your normal kidney function. This partial loss of kidney function is often called chronic renal insufficiency. Anemia tends to worsen as kidney disease progresses. End-stage kidney failure, the point at which dialysis or kidney transplantation becomes necessary, doesn't occur until you have only about 10 percent of your kidney function remaining. Nearly everyone with end-stage kidney failure has anemia.

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How is anemia diagnosed?

If a person has lost at least half of normal kidney function and has a low hematocrit, the most likely cause of anemia is decreased EPO production. The estimate of kidney function, also called the glomerular filtration rate, is based on a blood test that measures creatinine. Experts recommend that doctors begin a detailed evaluation of anemia in men and postmenopausal women on dialysis when the hematocrit falls below 37 percent. For women of childbearing age, evaluation should begin when the hematocrit falls below 33 percent. The evaluation will include tests for iron deficiency and blood loss in the stool to be certain there are no other reasons for the anemia.

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How is anemia treated?

EPO

If no other cause for anemia is found, it can be treated with a genetically engineered form of EPO. The EPO is usually injected under the skin two or three times a week. Patients on hemodialysis who can’t tolerate EPO shots may receive the hormone intravenously during treatment. The intravenous method, however, requires a larger, more expensive dose and may not be as effective.

The U.S. Food and Drug Administration (FDA) recommends that patients treated with EPO therapy should achieve a target hemoglobin between 10 and 12 grams per deciliter (g/dL). Recent studies have shown that raising the hemoglobin above 12 g/dL in people who have kidney disease increases the risk of heart attack, heart failure, and stroke. People who take EPO shots should have regular tests to monitor their hemoglobin. If it climbs above 12 g/dL, their doctor should prescribe a lower dose of EPO. The FDA recommends that patients whose hemoglobin does not rise to the target level with normal doses of EPO ask their doctor to check for other causes of anemia.

Medical Tests for Prostate Problems

The prostate is a walnut-sized gland in men that produces fluid that is a component of semen. The gland has two or more lobes—or sections—enclosed by an outer layer of tissue. Located in front of the rectum and just below the bladder, where urine is stored, the prostate surrounds the urethra, which is the canal through which urine passes out of the body.

The most common prostate problem in men under 50 is inflammation or infection, which is called prostatitis. Prostate enlargement is another common problem. Because the prostate normally continues to grow as a man matures, prostate enlargement, also called benign prostatic hyperplasia or BPH, is the most common prostate problem for men over 50. Older men are at risk for prostate cancer as well, but it is much less common than BPH.

Sometimes, different prostate problems have similar symptoms. For example, one man with prostatitis and another with BPH may both have a frequent, urgent need to urinate. Other men with BPH may have different symptoms. For example, one man may have trouble beginning a stream of urine, while another may have to get up to go to the bathroom frequently at night. A man in the early stages of prostate cancer may have no symptoms at all. This confusing array of symptoms makes a thorough medical examination and testing very important. Diagnosing the problem may require a series of tests.

Male urinary tract, front and side views.

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Talking With Your Doctor or Nurse

Letting your doctor or nurse know you have a problem is the first step. Try to give as many details about the problem as you can, including when it began and how often it occurs. Tell the doctor or nurse whether you have had recurrent urinary tract infections or symptoms such as pain after ejaculation or during urination, sudden strong urges to urinate, or hesitancy and a weak urine stream. You should talk about the medicines you take, both prescription medicines and those you can buy over the counter, because they might be part of the problem. You should also talk about how much fluid you typically drink each day, whether you use caffeine or alcohol, and whether your urine has an unusual color or odor. In turn, the doctor or nurse will ask you about your general medical history, including any major illnesses or surgeries.

Other typical questions are as follows:

• Over the past month or so, how often have you had to urinate again in less than 2 hours?

• Over the past month, from the time you went to bed at night until the time you got up in the morning, how many times a night did you typically get up to urinate?

• Over the past month or so, how often have you had a sensation of not emptying your bladder completely after you finished urinating?

• Over the past month or so, how often have you had a weak urinary stream?

• Over the past month or so, how often have you had to push or strain to begin urinating?

Your answers to these questions may help your doctor or nurse identify the problem or determine what tests are needed. You may also receive a symptom score evaluation that can be used as a baseline to see how effective later treatments are at relieving those symptoms.

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Preparing for the Exam

The common tests your doctor or nurse will perform first require no special preparation. Digital rectal exams (DRE) and blood tests for prostate-specific antigen (PSA) are often included in routine physical examinations for men over 50. For African-American men and men with a family history of prostate cancer, it is recommended that tests be given starting at age 40. Some organizations even recommend that these tests be given to all men starting at age 40.

If you have urination problems or if the DRE or PSA test indicates that you might have a problem, you will probably be given additional tests that may require some preparation. Ask your doctor or nurse whether you should change your diet or fluid intake or stop taking any medications. If the tests involve inserting instruments into the urethra or rectum, you may be given antibiotics before and after the test to prevent infection.

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Procedures

DRE

This exam is usually done first. Many doctors perform a DRE as part of a routine physical exam for any man over 50, some even at 40, whether the man has urinary problems or not. You may be asked to bend over a table or to lie on your side holding your knees close to your chest. The doctor slides a gloved, lubricated finger into the rectum and feels the part of the prostate that lies next to it. You may find the DRE slightly uncomfortable, but it is very brief. This exam tells the doctor whether the gland has any bumps, irregularities, soft spots, or hard spots that require additional tests. If a prostate infection is suspected, the doctor might massage the prostate during the DRE to obtain fluid for examination with a microscope.

Digital rectal exam (DRE).

PSA Blood Test

To rule out cancer, your doctor may recommend a PSA blood test. The amount of PSA, a protein produced by prostate cells, is often higher in the blood of men who have prostate cancer. However, an elevated level of PSA does not necessarily mean you have cancer. The Food and Drug Administration has approved a PSA test for use in conjunction with a DRE to help detect prostate cancer in men age 50 or older and for monitoring men with prostate cancer after treatment. However, much remains unknown about how to interpret the PSA test, its ability to discriminate between cancer and benign prostate conditions, and the best course of action if the PSA is high.