SPRINT trial: Lower systolic BP target reduces CV disease risk

SprintTrial_ToddAndersonResults from the Systolic Blood Pressure Intervention Trial (SPRINT) comparing the effectiveness of a systolic blood pressure target of <120 mm Hg vs. <140 mm Hg suggest that the <120 target significantly reduces risk for cardiovascular events, including death, in patients 50 years old and older with an increased risk of cardiovascular disease, said Paul K. Whelton, MB, MD, MSc, Chair of the SPRINT Steering Committee, who presented the results at Scientific Sessions 2015.

The trial found a 25 percent reduction in the rate of cardiovascular complications, including MI, heart failure and stroke in the group treated to under 120 mm Hg systolic blood pressure. There also was a 27 percent reduction in death from all causes, said Whelton, the Show Chwan Health System Chair in Global Public Health at Tulane University School of Public Health and Tropical Medicine, New Orleans.

The SPRINT researchers randomly assigned 9,361 patients from 102 medical centers and clinics across the United States who were at increased cardiovascular risk and with a systolic blood pressure of 130 to 180 mm Hg to either standard treatment or to intensive treatment. Standard treatment meant a systolic blood pressure target of less than 140 mm Hg, and intensive treatment meant a target of less than 120 mm Hg. Patients with diabetes mellitus or prior stroke were excluded.

Increased cardiovascular risk was defined as one or more of the following: clinical or subclinical cardiovascular disease other than stroke; chronic kidney disease, excluding polycystic kidney disease, with an estimated glomerular filtration rate (eGFR) of 20 to less than 60 ml per minute per 1.73 m2 of body-surface area; a 10-year risk of cardiovascular disease of 15 percent or greater on the basis of the Framingham risk score; or an age of 75 years or older.

The primary outcome of the study was a composite of first occurrence of MI, non-MI acute coronary syndrome, stroke, acute decompensated heart failure and cardiovascular disease death. The secondary outcomes included all-cause mortality and the incidence of decline in eGFR ≥ 50 percent or end stage renal disease (ESRD) for participants with chronic kidney disease at baseline. The participants’ blood pressure was monitored monthly for three months and every three months thereafter.

There was a median follow-up of 3.26 years, at which point the trial was stopped earlier than planned because the NIH determined the results were too positive to continue the study.

Three medications were needed, on average, to achieve the greater degree of blood pressure reduction in the intensive-treatment group, instead of two medications for the standard treatment group.

“Serious adverse events consisted mostly of hospitalizations associated with hypotension and syncope that were more common in the intensive treatment group compared to the standard treatment group,” Whelton said. “But those events did not seem to result in injurious falls. There was no difference between the two groups for injurious falls and no difference for bradycardia. There was more electrolyte abnormality in the intensive treatment group, which was not terribly surprising. There were more reports on hospital admissions and discharges for kidney injury or acute kidney failure in the intensive treatment group.”

“So to summarize and provide some conclusions, SPRINT examined the effects of more intensive hypertension therapy than is currently recommended in most guidelines. The participants were all U.S. adults 50 years of age or older with hypertension and an additional risk factor for cardiovascular disease.”

In study participants with chronic kidney disease at baseline, there was no difference in renal outcomes among the two treatment groups. In participants without chronic kidney disease at baseline, the incidence of an eGFR reduction of 30 percent or more was more common in the intensive treatment group, Whelton said.

“Overall, we interpret these results to show the benefits of more intensive blood pressure lowering substantially exceeded the potential for harm. I’m not dismissing that potential. We need to follow it up,” he concluded.

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