My Health

Kidney stones linked to greater chance of CKD

December 1, 2008 on 1:28 pm | In Uncategorized | Comments Off A study presented at a nephrologists' conference last month has provided scientific evidence to support what many physicians have long suspected. Patients who develop kidney stones are more likely to develop chronic kidney disease and end-stage renal disease.

"Kidney stones are not a traditionally recognized risk factor ... but clinicians know it," said Dr. Rajiv Saran, associate professor and director of the Kidney Epidemiology and Cost Center at the University of Michigan, Ann Arbor.

The paper presented at Renal Week 2008, the American Society of Nephrology's 41st Annual Meeting and Scientific Exposition in Philadelphia suggested that those with a history of kidney stones had a 60% increased risk of developing CKD when compared with a healthy control group. The additional chance of ESRD was 40%. Those with stones also had a 40% increased risk of having an elevated serum creatinine or a reduced estimated glomerular filtration rate.

The authors say this finding adds importance to strategies to avert kidney stones in those who tend to form them, such as prescribing certain medications or recommending dietary changes.

"This should tell us to be a little more vigilant and think about treating patients to prevent kidney stones," said John Lieske, MD, lead author and professor of medicine at the Mayo Clinic in Rochester, Minn.

Kidney stones increase the risk of developing chronic kidney disease by 60%.

But those researching this area also expressed caution in interpreting these findings. This epidemiological study showed an association, but not cause and effect. It's unclear why these two conditions would be linked.

"The issue is, 'is this real and why?' It's an intriguing observation that needs to be followed up," said Anton C. Schoolwerth, MD, a nephrologist and professor of medicine at Dartmouth-Hitchcock Medical Center in Lebanon, N.H.

Some experts theorize that the stones themselves, or treatment to destroy them, may cause damage that later progresses to CKD and ESRD. Or it may start earlier. The process of stone formation may begin the cascade, but this association also may be because the same medical conditions that increase the chance of stones also increase the possibility of these other problems.

"It could be that there are common risk factors," said Gary Curhan, MD, ScD, a nephrologist and physician investigator at Brigham and Women's Hospital in Boston. "[Kidney stones] may not be causal."

But while the link between kidney stones and kidney disease is an open question, the fact that problems with this organ are becoming more common is not. The number of people affected has grown by 30% over the past decade. Most will die of cardiovascular disease before the kidney fails, although ESRD also increased by 3.4% from 2005 to 2006. In response, the U.S. Renal Data System last month issued its first report on the subject, in conjunction with its annual paper rounding up ESRD statistics. About 27 million people have CKD. The condition accounts for 24% of Medicare costs. The ESRD population makes up about 1% of the Medicare population and 7% of the program's costs.

"The major focus on chronic kidney disease in this year's report acknowledges that this disorder is a growing public health issue deserving of wider public awareness and intensified scientific investigation," said Elias A. Zerhouni, MD. He was director of the National Institutes of Health at the time the report was issued.

CKD also is a subject of growing public health surveillance efforts and medical society attention. In June, the American Medical Association passed policy at its Annual Meeting in Chicago that called for the U.S. Preventive Services Task Force to consider developing guidelines on the screening, diagnosis and staging of the condition.

Statins, CRP test get boost from high-profile study

November 24, 2008 on 1:21 pm | In Uncategorized | Comments Off Results of a large-scale study offered significant evidence that statin drugs reduced cardiovascular disease risks for patients with normal cholesterol but high levels of an inflammatory marker. As a result, physicians now face the challenge of incorporating this promising, albeit incomplete, data into everyday preventive care.

For instance, testing for the inflammatory marker, high-sensitivity C-reactive protein, hasn't been a big part of the practice of Bob Gramling, MD, DSc, a family physician in Rochester, N.Y. But he expects that to change in the very near future.

"I will be asked to do it more," said Dr. Gramling, an assistant professor in family medicine as well as community and preventive medicine at the University of Rochester. "I'm going to be thinking about it more."

This point of view is gaining momentum because results from that heavily publicized trial -- the first to use hs-CRP to guide cardiovascular prevention rather than only assess risk -- were released Nov. 9 at the American Heart Assn.'s scientific sessions in New Orleans. They also were published in the Nov. 20 New England Journal of Medicine and attracted widespread media attention.

Researchers with the Justification for the Use of Statins in Prevention: An Intervention Trial Evaluating Rosuvastatin, or JUPITER, tracked 17,802 participants for just short of two years. They found that patients with high levels of hs-CRP but otherwise healthy cholesterol profiles who took 20 mg of this drug daily dramatically reduced their risks of cardiovascular events and death when compared with those who were taking placebos. Another pair of papers presented at the AHA meeting reinforced hs-CRP's potential for cardiovascular disease risk stratification.

The CRP test is not a part of the Framingham Risk Score.

"These findings suggest that adding hs-CRP levels to traditional risk factors could identify millions more adults for whom treatment with statins appears to lower the risk of heart attack," said Elizabeth G. Nabel, MD, director of the National Heart, Lung, and Blood Institute.

Most physicians concur that JUPITER is a significant study. But a great deal of disagreement still exists about how widespread hs-CRP testing should become and how often a prescription for statins is needed.

"It's a very important study. It was well done. The people who did it are to be congratulated," said Mark Hlatky, MD, a cardiologist and professor at California's Stanford University School of Medicine. He wrote the accompanying NEJM editorial. "But how do we generalize the results?"

What will be JUPITER's impact?

Whether to test for hs-CRP and how to respond to the numbers has been controversial for years. Physicians increasingly are using this marker to determine strategies for those at intermediate risk for cardiovascular disease. Several studies have suggested that it is an effective strategy, and the Reynolds Risk Score includes it. This risk assessment tool was designed by Paul Ridker, MD, the principal investigator of JUPITER. He also is one of the patent holders for the hs-CRP assay.

This biomarker, however, is not a part of the more widely used Framingham Risk Score. AHA guidelines say its role in directing prevention strategies is unclear, and several papers comparing it with other risk factor measures have not found that it adds much to an overall assessment.

The response to this latest development varied widely. For some physicians, this trial gave them the evidence for which they were waiting.

"I think it's very important and very significant," said Lawrence K. Monahan, MD, an internist in Roanoke, Va., and clinical professor at the University of Virginia School of Medicine and the Virginia College of Osteopathic Medicine. He added that he would "without a doubt" be testing for hs-CRP more often.

Others are more hesitant. The relative risk reduction was significant, but questions remain about how clinically meaningful it would be to apply cholesterol-lowering treatment to those whose baseline risk may not be that high. "What we have not seen is what were the absolute levels of risk, and how far did they go down," said Dr. Hlatky.

Another necessary step is to identify the characteristics that make some patients benefit more than others from this statin use.

Concerns also stem from the potential long-term implications of more people taking statins at even younger ages for an even longer portion of their lives -- issues not answered by this project. The study, which was originally planned to follow patients for five years, was halted after an average of 1.9 years because the immediate benefits were so significant.

"We could find after 15 to 20 years of statin use higher rates of some other life-threatening condition. We have the potential to create a fair amount of harm," Dr. Gramling said.

Others worry about the cost associated with hs-CRP testing and treating patients who have high levels of this marker but normal cholesterol, especially if they are prescribed rosuvastatin. This drug is one of the more expensive in its class, although several physicians said they would likely opt for a generic. But it's not clear if JUPITER's results can be generalized in this manner.

"My own personal belief is that for the same degree of lipid lowering, it doesn't matter much which statin you're on," Dr. Hlatky said.

In addition, some physicians were skeptical about the possible role the study's funder may have played in the results. AstraZeneca Pharmaceuticals, the manufacturer of rosuvastatin, paid for the research.

"This immediately makes me suspicious," said Elizabeth Gabay, MD, an internist at Interfaith Community Health Center in Bellingham, Wash. "I would like to see a study not paid for by a maker of a statin. Then I would be more inclined to believe the results." The study authors noted in the published report, though, that AstraZeneca had no access to the data before the paper was submitted for publication and played no part in data analyses or drafting the paper.

The company now plans to file an application with the Food and Drug Administration for an expanded indication for this drug, according to an AstraZeneca statement. Rosuvastatin currently has FDA approval as an add-on to dietary efforts to lower cholesterol. It is marketed by AstraZeneca as Crestor.

Reframing Framingham: New evidence prompts another look at cardiovascular risk algorithms

November 24, 2008 on 1:21 pm | In Uncategorized | Comments Off The Framingham Risk Score, the crystal ball that helps physicians determine who is most and least in need of intervention to reduce the chance of a heart attack, is the subject of increasing debate over how to make it more accurate.

"We are humbled when patients at low risk have events, and we know that the sensitivity of the score is a problem," said James De Lemos, MD, a cardiologist and associate professor of medicine at the University of Texas Southwestern Medical Center at Dallas.

A version of the calculator, a product of six decades of research conducted as part of the Framingham Heart Study, was first proposed in several papers appearing in 1976 in the American Journal of Cardiology. The articles detailed how various factors could be used to profile an individual patient's risks. The goal was to identify those most in need of prevention and give peace of mind to those who may have one elevated factor but otherwise are healthy.

"The importance of risk stratification is that it helps you focus without needlessly alarming or falsely reassuring people," said William Kannel, MD, MPH, then the director and now a senior investigator with the project.

Subsequent versions have been published over the years. The most recent one was in the May 12, 1998, Circulation. That risk calculator iteration was then simplified and incorporated into a report by the National Cholesterol Education Program Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults, which was published in the May 16, 2001, Journal of the American Medical Association. The current assessment incorporates age; total and HDL cholesterol; smoking status; systolic blood pressure; and whether a patient is taking an anti-hypertensive drug. Experts believe this tool is one of the reasons heart attack death rates have decreased. Still, a great deal of talk focuses on the tool's next revision.

Most people who have heart attacks and strokes were not considered high risk.

"The risk algorithm should continually be re-examined if new evidence comes along," said Christopher O'Donnell, MD, associate director of the Framingham Heart Study. "And I think there are three areas that are going to frame the next decade of risk assessment -- blood biomarkers, vascular imaging and genetic markers."

Experts also say an update is due for reasons beyond the fact that time has passed and additional data are available. The focus of risk assessment is changing, with researchers wanting to devise one tool to determine the risk of all cardiovascular conditions, not just myocardial infarction. In addition, a great deal of work is going into attempts to design more accurate assessments of those identified as having intermediate risk.

A paper published in the Feb. 14, 2007, JAMA by a group at Brigham and Women's Hospital in Boston, and another online Jan. 22 in Circulation by Framingham researchers, outlined strategies to determine the 10-year risk of any cardiovascular event. The JAMA paper, for instance, outlined the Reynolds Risk Score for women, incorporating traditional risk factors along with family history and C-reactive protein, both of which are the most likely candidates to be included in future versions of Framingham. Approximately 40% to 50% of women at intermediate risk were reclassified as having a high or low chance of a cardiovascular event. A men's version was released at the American Heart Assn. meeting in New Orleans last month.

"The bottom line of both [Framingham and Reynolds] risk scores is getting the right drug to the right patient at the right time," said Paul Ridker, MD, lead author of the JAMA paper and director of the Center for Cardiovascular Disease Prevention at Brigham and Women's Hospital. "The majority of heart attacks and strokes occur in apparently healthy men and women of intermediate risk. How can we better define high and low risk within the intermediate risk group? We did it with greatly improved accuracy by adding two simple things to do a better job of getting patients stratified."

Researchers also want to create tools that don't require blood draws or multiple patient visits. The more recent Circulation document provided two means of risk assessment. One relied on the usual Framingham risk factors, and the other substituted body mass index for cholesterol numbers.

National survey will explore what it takes to age well in America

November 24, 2008 on 1:21 pm | In Uncategorized | Comments Off Washington -- Understanding the medical care, technology and economic wherewithal it takes to age well in the U.S. is the goal of a new survey funded by the National Institute on Aging and led by Johns Hopkins University's Bloomberg School of Public Health in Baltimore.

NIA intends to provide about $24 million over the next five years to develop and implement the survey. Still in its earliest phase, the survey aims to further understanding of how older people overcome obstacles in daily life -- whether by installing grab bars in a bathroom or by having joint replacement surgery.

The surveyors also plan to include measures related to social interactions by asking, for example, whether a person does any volunteer work.

Since nearly 40 million people in the nation are already 65 or older, and most are expected to live about 20 more years, finding ways for people to continue to function is in everyone's interest. The AMA is putting forth a major effort to guide physicians as they care for aging patients, with resources ranging from guidelines on the use of assistive technology and the safety of older drivers to dementia and assistance to caregivers.

The new survey will pick up on trends noted in the "1982-2004 National Long-Term Care Survey," which showed a major decline in disability among people 65 and older.

Nearly 40 million people in the U.S. are 65 or older.

"Our aim is to provide scientific evidence that can help in reducing disability and improving the daily lives of older people," said the project's principal investigator Judy Kasper, PhD, professor in the Dept. of Health Policy and Management at Hopkins' School of Public Health.

Data released earlier this year by the Federal Interagency Forum on Aging-Related Statistics also show that as life expectancy increased, older people were, for the most part, enjoying better health and financial security than in the past.

The new study will try to zero in on how people are achieving these gains. "We hope that this study will play a critical role in maintaining or accelerating this trend as we address the challenges of our aging population," said Richard Suzman, PhD, director of the Division of Behavioral and Social Research at NIA.

Questions on the economic consequences of aging also will be asked, said Kasper. For example: "How do people pay for services when they need them for long-term disability problems?"

Evidence from earlier reports also revealed that while disabilities have been declining, gains were not as great for blacks and Hispanics or for low-income seniors as for others.

To address these disparities, the survey population will include more people from minority and low-income groups to ensure they are well-represented, said Kasper.

Today's generation of people 65 and older is less likely to be disabled than this age group was before 1984.

The first phase of the study will sign up 12,000 Medicare enrollees who will be followed annually. The enrollees will be grouped by age. As people age into older groups, researchers will bring in younger people to replace them.

The resulting database is expected to prove valuable to researchers and policymakers, said Kasper. "In addition to design and data collection, an important piece is the dissemination of data to the research community and workshops to get people interested in using the data."

It's rare to start a new national survey of this size given the current constraints on research funding, said Kasper. "The NIA deserves a lot of credit for recognizing that our existing national surveys are not designed to address the kinds of issues this survey is designed to address."

The undertaking will include investigators from the University of Medicine and Dentistry of New Jersey; Brown University in Providence, R.I.; Columbia University in New York City; the Medical College of Wisconsin; the Urban Institute, a nonpartisan economic and social policy research group in Washington, D.C.; the University of Iowa; Syracuse University in New York; and the survey research firm, Westat in Maryland.

Smoking heightens aortic rupture risk for women

November 17, 2008 on 1:14 pm | In Uncategorized | Comments Off Washington -- Add another strong incentive to the list of reasons for women smokers to quit: abdominal aortic aneurysms.

A study posted online Oct. 14 in the British Medical Journal found that women who smoke were four times more likely to have an abdominal aortic aneurysm repair or rupture than women who had stopped. Women smokers also were eight times more likely to have the serious medical emergency occur than were women who had never smoked.

Most studies of AAA have focused on men. This study is believed to be the largest conducted on women.

"We've known that smoking confers a very high risk of AAA," said the study's lead author, Frank Lederle, MD, professor of medicine at the University of Minnesota and an internist at the Minneapolis VA Medical Center. The study's aim was to reach a better understanding of factors associated with AAA in women, the authors write.

"This study does provide another reason to quit smoking," he said.

Aortic aneurysms cause 15,000 deaths a year in the U.S.

The ballooning of the artery wall is more common in men older than 60 but may be more deadly for women, possibly rupturing at a smaller diameter. Aortic aneurysms cause about 15,000 deaths a year in the United States, with most originating in the abdomen. About 40% of the deaths occur in women.

"Women may not be getting the attention they should, especially women with a family history for AAA and who are smokers. They should be considered for screening," said David Neschis, MD, a vascular surgeon and associate professor of surgery at the University of Maryland's School of Medicine. Dr. Neschis was not involved with the study.

AAA has a high risk of mortality. Only a small number of people make it to the hospital alive, and those who do have about a 50-50 chance of death, Dr. Neschis said. "So the best way to treat these patients is to identify them before rupture and fix them." The bulging arteries are difficult to detect in a physical exam, so ultrasound scans of the abdomen are recommended.

"A screening ultrasound of the belly takes minutes, has no risk, is inexpensive in medical terms and is available at even the smallest community hospital," Dr. Neschis said.

The Agency for Healthcare Research and Quality recommends against routine screening in women but does recommend a one-time screening for men ages 65 to 75 who have ever smoked.

Reinforcing old warnings

The study's authors used data collected on 161,808 postmenopausal women enrolled in the Women's Health Initiative, a clinical trial that studied the effects of estrogen therapy, diet and vitamin D on heart disease, fractures, breast and cervical cancer. The main study ended in 2005.

During 7.8 years of follow-up, Dr. Lederle and colleagues found that 184 abdominal aneurysm repairs or ruptures were reported. The AAA's were strongly linked to age and smoking. Women in their late 60s were more likely to have been affected than were younger women.

Women smokers are 8 times more likely to have an abdominal aortic aneurysm than those who never smoked.

The principal messages for physicians are not new, said Janet Powell, MD, PhD, a professor of vascular surgery at the Imperial College in London and an author of an accompanying editorial. "More efforts must be made to stop women from smoking, and AAA must be high on the list of differential diagnoses in older women smokers who present with collapse and abdominal or back pain."

The connection between smoking and the entire world of heart disease isn't a surprise, said Vincent Bufalino, MD, an American Heart Assn. spokesman and president and CEO of Midwest Heart Specialists in Naperville, Ill. "Of the women I see with heart disease, far and away the majority are smokers. Either diabetes or smoking are the two biggest predictors of coronary heart disease."

Joel Dunnington, MD, a consultant on smoking issues for the Texas Medical Assn., would like physicians to counsel patients about the many risks of smoking, including AAA. And patients should be told that if they quit smoking at age 40, 50 or even 60, their risk levels quickly decline, he said. Dr. Dunnington is also an associate professor of radiology at the M.D. Anderson Cancer Center at the University of Texas in Houston.

The study also turned up a couple of other findings, Dr. Lederle said. For example, it was determined that hormone therapy provided protection from AAA events. This conclusion was in contrast to previous smaller studies, which found that estrogen alone may increase risk.

"That was a surprise," Dr. Lederle said. "It hadn't been shown before and needs to be confirmed. We certainly aren't suggesting that people go out and take hormones, but it does suggest there is a role for female hormones in providing protection from AAA, which might explain why there are fewer in women."

In another finding, diabetes also conveyed protection to women. Although this has been seen in previous studies among men, whether it occurred among women had been uncertain, the researchers write. But why this negative association occurs has yet to be explained.