Effect of proanthocyanidins on blood pressure: A systematic review and meta-analysis of randomized controlled trials.

Abstract

BACKGROUND\nHypertension is a common chronic disease that can lead to serious health problems. Previous studies have not drawn a consistent conclusion about the effect of proanthocyanidins (PCs) on blood pressure (BP). This systematic review and meta-analysis aims to evaluate the effect of PCs supplementation on blood pressure (BP).\n\n\nMETHODS\nA comprehensive literature search was performed in 6 databases (Pubmed, Scopus, ISI Web of Science, the Cochrane Library, Embase and Google Scholar) to identify the randomized controlled trials (RCTs) that evaluated the BP-lowering effect of PCs. Subgroup and sensitivity analyses were conducted to evaluate the potential heterogeneity. Meta-regression analysis was used to evaluate dose effects of PCs on BP.\n\n\nRESULTS\nA total of 6 studies comprising 376 subjects were included in our meta-analysis to estimate the pooled effect size. This meta-analysis suggested that PCs supplementation could significantly reduce systolic blood pressure (SBP) (WMD: -4.598\u2009mmHg; 95% CI: -8.037, -1.159; I2\u2009=\u200933.7%; p\u2009=\u20090.009), diastolic blood pressure (DBP) (WMD: -2.750\u2009mmHg; 95% CI: -5.087, -0.412; I2\u2009=\u20090.0%; p\u2009=\u20090.021) and mean arterial pressure (MAP) (WMD: -3.366\u2009mmHg; 95% CI: -6.719, -0.041\u2009mmHg; I2\u2009=\u20090.0%; p\u2009=\u20090.049), but had no significant effect on pulse pressure (PP) (WMD: -2.131\u2009mmHg; 95% CI: -6.292, 2.030; I2\u2009=\u20090.0%; p\u2009=\u20090.315). When the studies were stratified according to the duration of the study, there was a significant reduction on SBP in the subset of the trials with <12 weeks of duration. On the contrary, there was a significant reduction on DBP in the subset of the trials with ≥12 weeks of duration. The Subgroup analysis by BMI indicated that a significant reduction on SBP for people with a higher BMI (BMI\u2009≥\u200925) and a significant reduction on DBP for people with a lower BMI (BMI\u2009<\u200925). Additional subgroup analysis revealed low-dose-PCs (<245\u2009mg/day) could significantly reduce SBP, DBP and MAP. The meta-regression analyses did not indicate the dose effects of PCs on SBP, DBP, PP and MAP.\n\n\nCONCLUSION\nBased on the current findings, PCs supplementation may be a useful treatment of hypertensive patients as well as a preventive measure in the prehypertensive and healthy subjects. However, further investigation is needed to confirm these results.