“Go Low” or “Say No” to Aggressive Systolic BP Goals?

STUDY SUMMARY
Treating to SBP < 120 mm Hg lowers mortality
The Systolic Blood Pressure Intervention Trial (SPRINT) was a multicenter RCT designed to determine if treating to lower SBP targets in nondiabetic patients at high risk for CV events improves outcomes, compared with standard care. Patients were at least 50, had an SBP of 130 to 180 mm Hg, and were at increased CV risk; the last was defined as clinical or subclinical CV disease other than stroke; CKD with a glomerular filtration rate (GFR) of 20 to 60 mL/min/1.73 m²; 10-year risk for CV disease > 15% on Framingham risk score; or age 75 or older. Patients with diabetes, prior stroke, polycystic kidney disease, significant proteinuria or symptomatic heart failure within the past six months, or left ventricular ejection fraction < 35% were excluded.¹

Patients (N = 9,361) were randomly assigned to an SBP target < 120 mm Hg in the intensive group or < 140 mm Hg in the standard treatment group, in an open-label design. Allocation was concealed. The study protocol encouraged, but did not require, the use of thiazide-type diuretics, loop diuretics (for those with advanced renal disease), ACE inhibitors or angiotensin receptor blockers, calcium channel blockers, and ß-blockers. Clinicians could add other agents as needed. All major classes of antihypertensives were used.

Medication dosing adjustments were based on the average of three BP measurements taken with an automated measurement system with the patient seated after 5 minutes of quiet rest. Target SBP in the standard therapy group was 135 to 139 mm Hg. Medication dosages were lowered if SBP was < 130 mm Hg at a single visit or < 135 mm Hg at two consecutive visits.¹

The primary composite outcome included the first occurrence of MI, acute coronary syndrome, stroke, heart failure, or death from CV causes. Secondary outcomes were the individual components of the primary composite outcome; death from any cause; and the composite of the primary outcome or death from any cause.¹

Study halted early. The study was stopped early due to significantly lower rates of the primary outcome in the intensive therapy group versus the standard therapy group (1.65% vs 2.19% per year, respectively; hazard ratio [HR], 0.75 with intensive treatment). The resulting median follow-up time was 3.26 years.¹ This corresponds to a 25% lower relative risk for the primary outcome, with a decrease in event rates from 6.8% to 5.2% over the trial period. All-cause mortality was also lower in the intensive therapy group: 3.4% vs 4.5% (HR, 0.73).

The number needed to treat (NNT) over 3.26 years to prevent a primary outcome event, death from any cause, and death from CV causes was 61, 90, and 172, respectively. Serious adverse events occurred more frequently in the intensive therapy group than in the standard therapy group (38.3% vs 37.1%; HR, 1.04), with a number needed to harm (NNH) of 46 over the study period.¹

Rates of serious adverse events that were identified as likely associated with the intervention were 4.7% vs 2.5%, respectively. Hypotension, syncope, electrolyte abnormalities, and acute kidney injury/acute renal failure reached statistical significance. The incidence of bradycardia and injurious falls, although higher in the intensive treatment group, did not reach statistical significance. In the subgroup of patients 75 or older, 48% in each study group experienced a serious adverse event.¹

Throughout the study, mean SBP was 121.5 mm Hg in the intensive therapy group and 134.6 mm Hg in the standard treatment group. Patients in the intensive therapy group required, on average, one additional BP medication, compared to those in the standard treatment group (2.8 vs 1.8, respectively).¹

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