Monday, July 8, 2013

Medicating mild hypertension: is more evidence needed?

- Kenny Lin, MD, MPH

In the July 1st issue of American Family Physician, Dr. Janelle Guirguis-Blake commented on a Cochrane Review that found no benefits from pharmacotherapy for mild hypertension (systolic blood pressure of 140 to 159 mm Hg and/or diastolic blood pressure of 90 to 99 mm Hg) on cardiovascular outcomes or mortality. However, the randomized trials' relatively small number of participants (fewer than 9000) and short follow-up periods (five years or less) left open the possibility that a significant benefit could still exist. Therefore, Dr. Guirguis-Blake concluded: "Larger double-blinded RCTs in this population of patients with stage 1 hypertension are needed to clarify the potential long-term benefits of pharmacologic therapy."

When existing research does not adequately answer an important clinical question - in this case, are medications superior to lifestyle modifications or no treatment for mild hypertension? - researchers invariably recommend collecting more evidence. But is performing a large randomized trial of mild hypertension management feasible, given that the standard of care set in 2003 by the Seventh Report of the Joint National Committee (JNC-7) (and reflected in this AFP Point-of-Care Guide) is to routinely identify and treat blood pressures in this range? The U.S. Preventive Services Task Force apparently thinks so; after previously declaring that the benefits of screening were "well established," the USPSTF has released an extensive draft research plan to reevaluate benefits, harms, best methods, and recommended intervals for screening for high blood pressure in adults.

With the next USPSTF statement at least a few years down the road, current evidence-based guidance on hypertension management is limited. The U.S. National Heart, Lung, and Blood Institute, which convened the previous JNC panels, recently announced in a cardiology journal its intention to stop producing guidelines. Instead, it says it will partner with outside medical groups to release its long-delayed JNC-8 hypertension guideline. Since guidelines sponsored by subspecialty societies are less likely to adhere to Institute of Medicine standards for producing unbiased guidelines, family physicians and other primary care clinicians should advocate for their organizations to participate in this process.