Effect of Pycnogenol on Blood Pressure. Findings From a PRISMA Compliant Systematic Review and Meta-Analysis of Randomized, Double-Blind, Placebo-Controlled, Clinical Studies

Results of previous clinical trials evaluating the effect of pycnogenol supplementation on blood pressure (BP) are controversial. Therefore, we aimed to assess the impact of pycnogenol on BP through a systematic review of literature and meta-analysis of available randomized, double-blind, placebo-controlled clinical studies (randomized clinical trials [RCTs]). Literature search included SCOPUS, PubMed-Medline, ISI Web of Science, and Google Scholar databases up to January 10, 2019 to identify RCTs investigating the impact of pycnogenol on BP. Two investigators independently extracted data on study characteristics, methods, and outcomes. This systematic review and meta-analysis is registered in International Prospective Register of Systematic Reviews (PROSPERO) under number CRD42018112172. Overall, the impact of pycnogenol on BP was reported in 7 trials involving 626 participants. Meta-analysis did not suggest any significant improvement in systolic BP (weighted mean difference [WMD]: -0.028 mm Hg; 95% confidence interval [CI]: -0.182 to 0.127; P = .726; I2 = 46%), diastolic BP (WMD: -0.144 mm Hg; 95% CI: -0.299 to 0.010; P = .067; I2 = 0%), mean arterial pressure (WMD: -0.091 mm Hg; 95% CI: -0.246 to 0.063; P = .246; I2 = 0%), and pulse pressure (WMD: -0.003 mm Hg; 95% CI: -0.151 to 0.158; P = .966; I2 = 0%) following pycnogenol treatment. Results persisted in the leave-one-out sensitivity analysis. Therefore, the present meta-analysis does not suggest any significant effect of pycnogenol on BP.