By Martina M. McGrath, MD
July 6, 2016
Published in November 2015, the Systolic Blood Pressure Intervention Trial (SPRINT) study (N Engl J Med 2015;373:2103-2116) sought to address the question of the optimal blood pressure target for patients at risk of cardiovascular disease.
This randomized controlled trial examined intensive versus standard treatment of hypertension in patients aged over 50 years with systolic blood pressure (SBP) of 130-180mmHg and increased cardiovascular risk. Important groups excluded were those with diabetes, difficult-to-control blood pressure, a history of stroke, cardiovascular events or procedures within the prior 3 months, or symptomatic heart failure within the previous six months.
9361 patients were enrolled with planned five-year follow up. Target SBPs were SBP-differed by 13.1mmHg between the groups, with the intensive group requiring on average one more antihypertensive agent than the standard treatment group.
The study was terminated early, at a median follow up of 3.26 years, due to a significant lowering in the incidence of the primary end point in the intensive treatment arm; 1.65% vs 2.19% per year, (HR 0.75, 95% CI 0.60-0.90, p <0.001). This effect was driven largely by a decrease in incidence of congestive cardiac failure, death from cardiovascular disease and a lower risk of death from any cause. The relative risk of death from cardiovascular cause was 43% lower in the intensive arm.
Serious adverse events were predictable, with higher rates of syncope, hypotension, acute kidney injury and electrolyte abnormalities in the intensive treatment group. The long-term effect on renal outcomes is unclear and requires further study.
SPRINT has again thrown open the debate on target blood pressure in high-risk individuals and challenges the recommendations of recent JNC 8 guidelines. To achieve its blood pressure targets would require considerable commitment and resources but the magnitude of the observed effect challenges us as physicians to increase efforts to achieve these goals.
Dr. Martina McGrath is an Instructor in Medicine at Harvard Medical School, and a member of the Renal Division, Department of Medicine, at Brigham and Women’s Hospital, both in Boston.