The SPRINT: Intensive vs. standard blood pressure control [Classics Series]

1. In patients with hypertension and elevated cardiovascular risk, treating to a target systolic blood pressure of 120 mmHg significantly reduced the risk of heart failure and cardiovascular mortality when compared with the standard target of 140 mmHg.

2. Patients in the intensive group experienced significantly higher rates of hypotension, syncope, electrolyte abnormalities, and acute kidney injury compared to those in the standard group.

Original Date of Publication: November 2015

Study Rundown: The prevalence of hypertension has been estimated at approximately 1 billion globally. Prior studies have shown that treating hypertension significantly reduces the risk of stroke, myocardial infarction, and heart failure, though the blood pressure target for treatment remains unclear. Current guidelines generally recommend a target systolic blood pressure (sBP) of less then 130 to 150 mmHg, depending on a patient’s comorbidities. Lower sBP targets, however, have been linked with lower risk of cardiovascular outcomes.

The Systolic Blood Pressure Intervention Trial (SPRINT) explored the effects of lowering sBP to a target of 120 mmHg compared to a target of 140 mmHg in patients with hypertension and elevated cardiovascular risk. The study found that intensive treatment to an sBP target of 120 mmHg significantly reduced the risk of heart failure and cardiovascular mortality compared to a target of 140 mmHg. Patients in the intensive group also experienced significantly lower overall mortality. Compared to the standard target, patients in the intensive group experienced significantly higher rates of hypotension, syncope, electrolyte abnormalities, and acute kidney injury. It is important to note that patients with diabetes mellitus and previous stroke were excluded from this study.

Click to read the study in NEJM

In-Depth [randomized controlled trial]: Patients were eligible if they were ≥50 years of age, had sBP from 130-180 mmHg, and an increased risk of cardiovascular events (clinical/subclinical cardiovascular disease other than stroke, chronic kidney disease, 10-year Framingham risk ≥15%, ≥75 years of age). Patients with diabetes mellitus or prior stroke were not eligible. A total of 9361 patients were randomized to the standard-treatment group (sBP <140 mmHg) or the intensive-treatment group (sBP <120 mmHg). Treatment protocols encouraged, but did not mandate, the use of specific antihypertensives, including thiazides as first-line therapy, loop diuretics, and beta-blockers. The primary outcome was a composite of myocardial infarction, other acute coronary syndrome, stroke, acute decompensated heart failure, or cardiovascular death. Renal outcomes were also assessed separately in patients with and without chronic kidney disease. In patients with chronic kidney disease, this was a composite of a decrease in estimated glomerular filtration rate (eGFR) by ≥50% or end-stage renal disease requiring dialysis or transplantation. In those without, the outcome was a composite of a decrease in eGFR by ≥30% to <60 mL/min/1.73 m².

The median follow-up was 3.26 years and the trial was stopped early. Throughout the follow-up period, mean sBP was 121.5 mmHg in the intensive group and 134.6 mmHg in the standard group. The mean number of antihypertensive medications used was 2.8 and 1.8 in the intensive and standard groups, respectively.

Patients in the intensive group experienced significantly lower rates of the primary outcome when compared with the standard group (HR 0.75, 95%CI 0.64 to 0.89, p < 0.001). This separation was apparent within the first year of follow-up, and was driven by reductions in heart failure (HR 0.62, 95%CI 0.45 to 0.84, p = 0.002) and cardiovascular death (HR 0.57, 95%CI 0.38 to 0.85, p = 0.005). The intensive group also experienced significantly fewer deaths compared to the standard group (HR 0.73, 95%CI 0.60 to 0.90, p = 0.003), and this difference became significant within 2 years after randomization. In patients with CKD, there were no significant differences between the groups in the renal outcome. In patients without CKD, those in the intensive group experienced significantly higher rates of eGFR decline than those in the standard group (HR 3.49, 95%CI 2.44 to 5.10, p < 0.001).

The rates of serious adverse events were similar in the two groups. The intensive group experienced significantly higher rates of hypotension (2.4% vs. 1.4%, p = 0.001), syncope (2.3% vs. 1.7%, p = 0.05), electrolyte abnormality (3.1% vs. 2.3%, p = 0.02), and acute kidney injury (4.1% vs. 2.5%, p < 0.001).

Image: PD

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