Effects of blood pressure lowering on outcome incidence in hypertension. 1. Overview, meta-analyses, and meta-regression analyses of randomized trials

Background: Antihypertensive treatment is based on randomized controlled trials (RCTs) started since 1966. Meta-analyses comprehensive of all RCTs but limited to RCTs investigating blood pressure (BP) lowering in hypertensive patients are lacking. Objectives: Two clinical questions were investigated: the extent of different outcome reductions by BP lowering in hypertensive patients, and the proportionality of outcome reductions to SBP, DBP, and pulse pressure (PP) reductions. Methods: PubMed between 1966 and December 2013 (any language), Cochrane Collaboration Library and previous overviews were used as data sources for identifying and selecting all RCTs comparing the antihypertensive drugs with placebo or less intense BP lowering (intentional BP-lowering RCTs); comparing BP-lowering drugs with placebo without BP-lowering intention, but with BP difference (nonintentional BPlowering RCTs); and enrolling at least 40% hypertensive patients. RCTs on acute myocardial infarction, heart failu...