Efficacy and Safety of Polyphenols for Osteoarthritis Treatment: A Meta-Analysis.

PURPOSE: Osteoarthritis (OA) is a chronic and degenerative disorder associated with joint pain and loss of joint function. It is reported that polyphenols could yield articular benefits in patients with OA through the inhabitation of key inflammatory pathways. This meta-analysis was conducted to assess the efficacy and safety of polyphenol products for OA treatment. METHODS: This study included searches of PubMed, EMBASE, and the Cochrane Library databases from inception to November 6, 2019. Randomized controlled trials (RCTs) comparing polyphenols versus NSAIDs or placebo for human OA were included. Standardized mean differences (SMD) or risk ratios (RRs) were calculated for all relevant outcomes. Meta-analyses were conducted by using random effect models, and heterogeneity was assessed by using the I2 statistic. FINDINGS: A total of 18 RCTs (N = 1724) were eligible for analysis. Polyphenol products showed a significant advantage over placebo on pain relief (SMD, -1.11; 95% CI, -1.35 to -0.87) and functional improvement (SMD, -1.14; 95% CI, -1.38 to -0.90). No differences in safety outcomes were detected between polyphenols and placebo. There were no differences in efficacy outcomes between polyphenols and NSAIDs, although patients receiving polyphenols had a lower but nonsignificant risk of experiencing gastrointestinal dysfunction compared with those treated with NSAIDs. Polyphenols and NSAIDs in combination yielded more significant benefits in efficacy than NSAIDs alone. IMPLICATIONS: The results of our study suggest that polyphenols may be a promising alternative for OA by relieving symptoms while reducing safety risks. However, the generalizability of our results may be limited by the quality and sample size of the available research, as well as the heterogeneity between RCTs. High-quality clinical trials are needed to make meaningful clinical practice recommendations.