Since the American College of Cardiology and the American Heart Association lowered the threshold for hypertension to 130/80 millimeters of mercury in November, cardiologists have questioned the risk-benefit balance of the new guidelines.
Of course, many of the newly hypertensive patients in the 130/80 to 140/90 range are recommended to be treated with lifestyle modifications alone, but millions in the U.S. will also be eligible for drug therapy.
To help clinicians address these treatment decisions, Robert A. Phillips, MD, PhD, with Houston Methodist Hospital, and colleagues projected the odds of benefit versus harm with intensive treatment for the SPRINT trial population. They published findings online March 7 in the Journal of the American College of Cardiology.
Phillips and colleagues stratified the population into quartiles based on expected cardiovascular disease (CVD) risk over a 10-year period. They found treatment to a systolic blood pressure (SBP) goal below 130 mm Hg—compared to 140 mm Hg—would be associated with more serious adverse events (SAEs) than preventable deaths in the two lower-risk quartiles. However, as the baseline CVD risk level rose, the benefit gained from lower mortality outweighed the potential for SAEs.
"Classifying patients by degree of future risk might be the best way to identify who could benefit most from intensive treatment," Phillips said in a press release. "We developed a model using the 10-year cardiovascular disease risk and found that aggressive treatment of patients with a risk greater than or equal to 18.2 percent would result in more benefit than harm, while those with a risk of less than that would fare better under a standard blood pressure management approach."
SPRINT examined the effect of treatment to a SBP below 120 mm Hg with a then-standard threshold of 140 mm Hg for patients in their 50s or older who were at risk for cardiovascular events. The more intensive treatment therapy group achieved lower SBPs with better clinical outcomes than the standardly treated group, contributing to the new ACC/AHA guidelines. The assessment technique used in SPRINT has generated some controversy because the approach generally yields an SBP that is 7 to 10 mm Hg lower than an office blood pressure measurement, the authors noted. However, the ACC/AHA attempted to adjust for this in their guideline, recognizing that the SBP target of 120 mm Hg in the SPRINT trial is equal to the 130 mm Hg target in clinical practice.
Phillips and colleagues pointed out the guidelines recommended an SBP target below 130 mm Hg for all hypertensive individuals with 10-year CVD risk above 10 percent. Their analysis, however, suggests fewer patients should be treated so aggressively—only those with predicted 10-year CVD risk at or above 18.2 percent. For lower-risk patients, an SBP goal of 140 mm Hg might be more appropriate, the authors noted.
“Prospective studies are needed to confirm whether these projections translate directly to clinical practice and how they may be modified by specific antihypertensive treatment regimens,” Phillips et al. wrote.