Friday, January 2, 2015

Can treating mild hypertension be too much medicine?

- Kenny Lin, MD, MPH

As part of a plan to improve our practice's quality of care for patients with high blood pressure, my office's nurse announces at every morning huddle which patients on that day's schedule had a blood pressure measurement of greater than 140/90 at their last visit. Most of these patients have measurements consistent with mild hypertension (systolic blood pressure less than 160 mm Hg and/or diastolic blood pressure less than 100 mm Hg). However, a previous AFP Community Blog post pointed out that the few randomized trials of anti-hypertensive medications in this population did not show improvements in cardiovascular outcomes or mortality.

In fact, some have gone as far to suggest that the identification and treatment of mild hypertension in persons at low cardiovascular risk may be "too much medicine," given the poor accuracy of office blood pressure measurements and that these patients typically receive drugs (and their accompanying side effects) rather than lifestyle change counseling. Last year's JNC 8 Guidelines for the Management of Hypertension in Adults added fuel to this controversy by acknowledging that no randomized trial evidence supports any systolic blood pressure treatment threshold in adults younger than 60 years, and recommending that adults 60 years and older receive medication only if their blood pressure is higher than 150/90.

In the first of a series of AFP editorials about overscreening, overdiagnosis, and overtreatment, Drs. Mark Ebell and Jessica Herzstein highlighted several examples of screening that does not improve patient-oriented outcomes: too-short intervals between screening colonoscopies; Pap smears in women after a hysterectomy for benign disease; and mammography in older women with dementia. Does looking for hypertension in adults without cardiovascular risk factors fall into this category as well?

new meta-analysis published in the Annals of Internal Medicine could tip the scales in favor of medicating adults with mild hypertension. Combining individual-patient data from a collaboration of blood pressure treatment trials with that from a previous Cochrane review, Dr. Johan Sundstrom and colleagues concluded that pharmacotherapy for mild hypertension reduced the relative risk of strokes, cardiovascular deaths, and total deaths by 22 to 28 percent after 5 years. (They estimated, however, that absolute risk reductions in contemporary primary care populations would be a modest 0.6 to 1.2 percent, or a number needed to treat of 83 to 167.)

Key take-home points are that the absolute benefits of treating otherwise healthy persons with mild hypertension are relatively small; lifestyle modification should generally precede medication; and blood pressure measurement should be performed and repeated carefully to ensure accurate identification of hypertensive patients. In a draft recommendation statement, the U.S. Preventive Services Task Force recently advised routine home blood pressure monitoring to confirm new hypertension diagnoses, which should hopefully limit overdiagnosis and overtreatment.