Objective: To estimate the effect of antihypertensive treatment in trials with baseline normotension and low levels of previous cardiovascular disease. To test if the results from SPRINT are compatible with those from other trials, and test the impact of SPRINT results on overall effect estimates.
Methods: Systematic review and meta-analysis of randomized controlled trials with at least 1000 patient-years of follow-up, comparing antihypertensive treatment versus placebo, or different blood pressure goals against each other. Trials with at least 50% previous cardiovascular disease were excluded.
Results: Sixteen trials, including 66 816 participants, were included in the meta-analyses. Mean baseline SBP was 138 mmHg, and mean difference between treatment arms was 5.5 mmHg. Antihypertensive treatment was associated with a neutral effect on all-cause mortality [relative risk 0.98, 95% confidence interval (CI) 0.92-1.05] and major cardiovascular events (0.97, 0.91-1.03). Results from SPRINT differed significantly from those of other trials (P = 0.012 for all-cause mortality; P = 0.016 for major cardiovascular events), but overall effect estimates were similar when SPRINT was excluded (1.01, 0.95-1.06 for all-cause mortality; 0.98, 0.93-1.03 for major cardiovascular events). Treatment was associated with reduced risk of secondary outcomes stroke (0.84, 0.71-1.00) and heart failure (0.88, 0.78-0.98), although heterogeneity was high in the stroke analysis (I = 54%).
Conclusion: SPRINT results are not representative for trials with baseline normotension and low levels of previous cardiovascular disease. Antihypertensive treatment does not protect against death or major cardiovascular events in this setting.