For people at high risk of cardiovascular events but without diabetes, targeting a systolic blood pressure of less than 120 mm Hg, compared with a target of less than 140 mm Hg, may reduce the risk of fatal and nonfatal major cardiovascular events and death from any cause, according to research published online ahead of print November 9 in New England Journal of Medicine. The lower systolic blood pressure target may not significantly reduce the risk of stroke, however, compared with the higher target. The lower target also may increase patients’ risk of adverse events.
The research “provides evidence of benefits for an even lower systolic blood pressure target than that currently recommended in most patients with hypertension,” said Jackson T. Wright Jr., MD, PhD, Program Director of the William T. Dahms Clinical Research Unit at University Hospitals Case Medical Center in Cleveland. Approximately half of Americans control their blood pressure to a level less than 140/90 mm Hg, which may be a challenging target. “Achieving a systolic blood pressure goal of less than 120 mm Hg in the overall population of patients with hypertension would be more demanding and time-consuming for both providers and patients than achieving a goal of 140 mm Hg, and would necessitate increased medication costs and clinic visits,” said Dr. Wright.
The SPRINT Study
The appropriate systolic blood pressure target for people without diabetes is uncertain. Randomized controlled trials including patients with hypertension indicate the benefit of treatment to achieve a systolic blood pressure target of less than 150 mm Hg, but data about lower blood pressure targets are limited. In the Systolic Blood Pressure Intervention Trial (SPRINT), Dr. Wright and colleagues compared the benefit of treatment of systolic blood pressure to a target of less than 120 mm Hg with that of treatment to a target of less than 140 mm Hg.
The investigators conducted SPRINT, a randomized, controlled, open-label trial, at 102 clinical sites in the United States, including Puerto Rico. Eligible participants were age 50 or older, had a systolic blood pressure of 130 to 180 mm Hg, and had an increased risk of cardiovascular events. Increased cardiovascular risk was defined by one or more of the following factors: clinical or subclinical cardiovascular disease other than stroke, chronic kidney disease, a 10-year risk of cardiovascular disease of 15% or greater on the basis of the Framingham risk score, or an age of 75 or older. Researchers excluded people with diabetes or prior stroke.
Participants were assigned to a systolic blood pressure target of either less than 140 mm Hg (ie, the standard-treatment group) or less than 120 mm Hg (ie, the intensive-treatment group). Participants and study personnel were aware of the study-group assignments, but outcome adjudicators were not. Participants’ antihypertensive regimens were adjusted according to their study-group assignments. All major classes of antihypertensive agents were included in the formulary and were provided free to the participants. The investigators also encouraged lifestyle modification. Participants were seen monthly for the first three months and every three months thereafter.
The primary outcome was the composite outcome of myocardial infarction, acute coronary syndrome not resulting in myocardial infarction, stroke, acute decompensated heart failure, or death from cardiovascular causes. Secondary outcomes included the individual elements of the primary composite outcome, death from any cause, and the composite of the primary outcome or death from any cause.
Intensive Treatment Reduced Mortality
A total of 9,361 participants were enrolled in SPRINT. The trial was stopped early after analyses of the primary outcome exceeded the monitoring boundary at two consecutive time points. Median follow-up was 3.26 years of the planned average of five years.
At one year, the mean systolic blood pressure was 121.4 mm Hg in the intensive-treatment group and 136.2 mm Hg in the standard-treatment group. The average difference between groups was 14.8 mm Hg. The mean diastolic blood pressure at one year was 68.7 mm Hg in the intensive-treatment group and 76.3 mm Hg in the standard-treatment group. The mean number of blood pressure medications was 2.8 in the intensive-treatment group and 1.8 in the standard-treatment group.
A total of 243 patients (1.65% per year) in the intensive-treatment group and 319 patients (2.19% per year) in the standard-treatment group had a primary outcome event. The hazard ratio for these events was 0.75 in the intensive-treatment group. The between-group differences were consistent for all components of the primary outcome and other prespecified secondary outcomes. In all, 365 deaths occurred—155 in the intensive-treatment group and 210 in the standard-treatment group. The relative risk of death from cardiovascular causes was 43% lower with the intensive intervention than with the standard treatment.