“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.”
– Julia Lewis, M.D., professor of Medicine
Vanderbilt nephrologist Julia Lewis, M.D., professor of Medicine, says at least where chronic kidney disease patients are concerned, guidelines recommending blood pressures below 130/80 are not based on gold standard evidence. Lewis says the lower standard, recommended in 2003 by the National Heart, Lung, and Blood Institute (NHLBI), and reinforced last year in the National Kidney Foundations 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. We can say the body of evidence makes us believe this may be of benefit, but 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 lack randomized, controlled subgroups of patients with chronic kidney disease. She also described studies that either found no benefit for patients who achieved blood pressures lower than 130/80, or evidence that pressure in this lower range is associated with poorer outcomes for patients with chronic kidney disease.
For example, results of the NHLBI-funded Action to Control Cardiovascular Risk in Diabetes (ACCORD) Trial, released this past March, found no heart disease benefit for those with type 2 diabetes who achieved a systolic pressure of 120. In addition, ACCORD found negative effects on the kidneys of some patients, when compared with those who maintained the older guideline of less than 140/90.
“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. That amounts to a huge budget item in a world where we have to reflect carefully on how we spend our health care dollars. 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.
And 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 themselves, are looking for tools to use in oversight of care. Golper says guidelines are important, but they 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. When I helped to write the introduction to guidelines in ’97, we stated that they were intended for use by health care professionals trained in the care of patients and not for regulatory use. If I could write it again, I’d include “not for regulatory or medical legal use,” Golper said.
Lewis says she also has chronic kidney patients who do better with a blood pressure goal of 140/90 and lower. She 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.
Currently, a number of insurance carriers are examining the possibility of reimbursing doctors based on how well they maintain certain standards of patient care. Blood pressure guidelines are among the indicators being discussed. Golper is working with a Vanderbilt team, lead by Jim Jirjis. M.D., MBA, assistant professor of Medicine and Biomedical Informatics, and C. Wright Pinson, M.D., MBA, Deputy Vice Chancellor for Health Affairs and CEO of Hospitals and Clinics, to pilot performance standards for Vanderbilt physicians. But Golper says it is likely Vanderbilt will favor a performance indicator based on the attention paid to blood pressures above 130/80, not to achieving that pressure goal in every patient.
Meanwhile, a study gearing up to begin in the Fall may help answer some of Lewis’ questions. The SPRINT trial begins enrolling patients in September. Vanderbilt is a participating site. SPRINT will include chronic kidney patients as well as patients at risk for heart disease and will compare outcomes of those who are randomized to a systolic goal of less than 120 vs. less than 140 and will compare the renal and cardiovascular outcomes of the two groups.
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