Efficacy and Safety of Quarter-Dose Blood Pressure-Lowering Agents: A Systematic Review and Meta-Analysis of Randomized Controlled Trials.

There is a critical need for blood pressure–lowering strategies that have greater efficacy and minimal side effects. Low-dose combinations hold promise in this regard, but there are few data on very-low-dose therapy. We, therefore, conducted a systematic review and meta-analysis of randomized controlled trials with at least one quarter-dose and one placebo and standard-dose monotherapy arm. A search was conducted of Medline, Embase, Cochrane Registry, Food and Drug Administration, and European Medicinal Agency websites. Data on blood pressure and adverse events were pooled using a fixed-effect model, and bias was assessed using Cochrane risk of bias. The review included 42 trials involving 20 284 participants. Thirty-six comparisons evaluated quarter-dose with placebo and indicated a blood pressure reduction of −4.7/−2.4 mm Hg ( P P P P P