July 15, 2010

Nephrologist questions BP guidelines

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Julia Lewis, M.D., here taking Malcom Neel’s blood pressure, said current guidelines recommending lower blood pressures need to be reviewed more carefully. (photo by Anne Rayner)

Nephrologist questions BP guidelines

Could guidelines recommending lower blood pressures (130/80mmHg) for patients do more harm than good?

One Vanderbilt physician says it is a question that needs to be answered, especially at a time when compliance with such guidelines is being considered as a way to judge the quality of medical practice.

Vanderbilt nephrologist Julia Lewis, M.D., professor of Medicine, says at least where chronic kidney disease patients are concerned, the lower standard, recommended in 2003 by the National Heart, Lung and Blood Institute (NHLBI), and reinforced last year in the National Kidney Foundation’s KDOQI Clinical Practice Guidelines for Chronic Kidney Disease, is based more on bias than evidence.

“There are well-conducted, randomized clinical trials demonstrating the benefit of blood pressures less than 140/90 in a general population, but no such trials supporting a goal of less than 130/80 in any population. It should not be applied to a general population of chronic kidney disease patients as a guideline,” Lewis said.

Lewis reviewed the current literature in a special article in the June 24 online issue of the Journal of American Society of Nephrologists (JASN).

In the article, Lewis demonstrated that the studies used to set the guidelines not only lack randomized, controlled subgroups of patients with chronic kidney disease, but they often found no benefit — or poorer outcomes — for patients with chronic kidney disease whose doctors worked to help them achieve this lower pressure.

“Deciding as a nation that we are going to recommend a blood pressure goal that is that much lower has a huge impact on the health care system.

“Most patients would have to take one or two more medications to achieve this lower goal. I think it is important to have the data that the cost/benefit ratio is favorable as well as the risk/benefit ratio,” Lewis said.

Lewis is not the only one concerned about the guideline and its use.

“I just saw someone yesterday who does better if we don't aggressively try to drop his blood pressure,” said nephrologist Thomas Golper, M.D., professor of Medicine at Vanderbilt.

Golper, who took part in writing National Kidney Foundation guidelines in 1997, says Lewis brings up a critical and timely point. Regulators and quality inspectors, who are often not physicians, are looking for tools to use in oversight of care.

Golper said guidelines are important, but are not designed to be used to judge performance standards.

“Guidelines are well-intended, but they must be designed to allow for a physician to follow the patient's response to therapy and make logical adjustments based on the recommendations in the guidelines,” Golper said.

Lewis suggests researchers need to examine the hypothesis that there may be a lower limit to the range of blood pressures that are healthy for certain individuals.

“Don't get me wrong, the lower standard might turn out to be better, but we have to differentiate between believing it is better, and having evidence it is better,” Lewis said.