Final results from the landmark SPRINT study confirm that aggressive blood pressure (BP) management, targeting a systolic blood pressure (SBP) below 120 mm Hg, significantly reduces the risk for heart disease, stroke, and death from these diseases, as well as death from all causes.
The results include data on some outcome events from the trial that had yet to be adjudicated when the primary analysis was released in 2015, as well as posttrial observational follow-up data collected through July 2016.
Cora Lewis
The data confirm and enhance the earlier findings and show that “lower is better” when it comes to blood pressure, primary investigator Cora E. Lewis, MD, professor and chair, Department of Epidemiology, University of Alabama at Birmingham School of Public Health, told theheart.org | Medscape Cardiology.
Final results of the Systolic Blood Pressure Intervention Trial (SPRINT) were published in the May 20 issue of the New England Journal of Medicine.
For the trial, researchers enrolled 9361 adults 50 years and older with a SBP between 130 and 180 mm Hg who were at increased risk for cardiovascular disease (CVD) but did not have a history of diabetes or stroke. Patients were randomly assigned to an intensive treatment target (SBP < 120 mm Hg) or a standard treatment target (SBP < 140 mm Hg).
In the final analysis, the rate of the primary outcome was 1.77% per year in the intensive-treatment group and 2.40% per year in the standard-treatment group (hazard ratio [HR], 0.73; 95% CI, 0.63 – 0.86; P < .001), similar to the earlier SPRINT findings.
All-cause mortality was 1.06% per year in the intensive-treatment group and 1.41% per year in the standard-treatment group (HR, 0.75; 95% CI, 0.61 – 0.92; P = .006), again similar to the previous findings.
“These results were highly statistically significant. It is remarkable in a trial powered for a composite CVD outcome to obtain a significant benefit for total mortality,” Lewis commented.
She noted that one criticism of the initial SPRINT results was that, for the components of the primary outcome, only heart failure and death due to CVD were significantly lower in the intensively treated group.
“Heart failure can be difficult to diagnose from records in a clinical trial, and the critiques were that this was shaky evidence, given that more participants treated to less than 120 were on diuretics, which could decrease swelling, a key symptom of heart failure,” she explained.
“In these final results, SPRINT found that risk of myocardial infarction, heart failure, and death from CVD were significantly lower in the group treated to less than 120, and risk of the primary outcome, excluding heart failure, was still significantly lower in the more intensively treated group,” she noted.
After the trial phase ended, blood pressure treatment was returned to the participants’ usual source of medical care and the trial treatment goals were no longer pursued. SPRINT continued to collect data on the outcomes through July 2016. During this time, SBP rose 6.9 mm Hg in the intensive-treatment group and 2.6 mm Hg in the standard-treatment group.
“Putting all the data together from the trial phase and the phase after randomized interventions had been stopped, there was still a significant benefit for the more intensive treatment on the primary outcome and on death from all causes,” Lewis said.
In addition, a separate new analysis based on all the data showed significantly fewer first and recurrent primary outcome events with intensive treatment group than with standard treatment (435 vs 552; HR, 0.78; 95% CI, 0.69 – 0.89; P < .001).
Manageable Risk
The pattern of safety events in the final analysis was similar to the 2015 report. In the intervention period, rates of serious adverse events overall did not differ significantly between the groups. However, rates of hypotension, electrolyte abnormalities, syncope (none leading to injurious falls), and acute kidney injury were higher in the intensive-treatment group.
As in other SPRINT reports, “acute kidney injury safety events were generally mild and there was nearly complete recovery of kidney function within 1 year,” Lewis said. “This and other analyses we have published indicate this is probably a hemodynamic effect.”
“Intensive treatment can be well tolerated and is generally safe with proper patient selection and monitoring. There are advantages to intensive therapy, and some risks, but I don’t think the risks are such that we should just throw the idea of more intensive treatment out the window,” Lewis said.
Reached for comment, Carlos Santos-Gallego, MD, from the Icahn School of Medicine at Mount Sinai in New York City, said there has been “controversy” over whether intensive blood pressure control targeting systolic to below 120 mm Hg is beneficial.
“The original SPRINT trial is incredibly important, in that it conclusively demonstrated that among patients with hypertension and increased cardiovascular risk, targeting systolic blood pressure to below 120 mm Hg resulted in lower rates of adverse cardiovascular events and, importantly, all-cause mortality, than targeting the conventional target of 140 mm Hg,” he told theheart.org | Medscape Cardiology.
“This final report of the SPRINT trial basically consolidates, confirms, and corroborates the original SPRINT data,” he noted. However, the final data are “more robust, with additional primary outcome events and all events having been adjudicated by a central committee, and there is an additional observation period of 1 extra year in which the treatment has been discontinued,”
“Over time, we are becoming more and more certain that lower is better with blood pressure. We still have a long way to go, but the cardiology community is slowly becoming more intense in our treatment of blood pressure for our patients,” Santos-Gallego said.
The potential adverse effects of intensive blood pressure control are “very manageable,” he added.
Support for SPRINT was provided by the National Institutes of Health (NIH). Full disclosures for authors are available in the original article. Santos-Gallego has no relevant disclosures.
N Engl J Med. 2021;384:1921-1930. Abstract
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