Effects of blood pressure lowering on outcome incidence in hypertension: 2. Effects at different baseline and achieved blood pressure levels - overview and meta-analyses of randomized trials

Background: Relevant clinical questions not approached by randomized controlled trials (RCTs) of blood pressure (BP)-lowering treatment can be explored by meta-analyses stratified by clinical criteria. Objectives: Investigating whether all grades of hypertension benefit from BP-lowering treatment and which are the target BP levels to maximize outcome reduction. Methods: Of the 68 RCTs of intentional and nonintentional BP-lowering, those without baseline antihypertensive drugs were stratified by the average baseline SBP and DBP (hypertension grades 1, 2, and 3). RCTs with or without baseline treatment were considered for investigating the effects of mean achieved SBP/DBP across three SBP cutoffs and two DBP cutoffs. Risk ratios (RR) and 95% confidence interval (CI) (random-effects model), standardized to 10/5mmHg SBP/DBP reduction, and absolute risk reductions of seven fatal and nonfatal outcomes were calculated. Differences between relative and absolute risk reductions in the different...