Efficacy and safety of the combination of glucosamine and chondroitin for knee osteoarthritis: a systematic review and meta-analysis

Aims Though glucosamine and chondroitin have become common practices for treating knee osteoarthritis, the clinical value of these two drugs in combination are still questionable. To evaluate the efficacy and safety of the combination of glucosamine (GS) and chondroitin (CS) in knee osteoarthritis (KOA) treatment. Methods We searched electronic databases, including PubMed, Embase, Web of Science, SCOPUS, The Cochrane Central Register of Controlled Trials (CENTRAL), OVID, Chinese Clinical Trial Registry (ChiCTR), CBM, CNKI, WanFang and VIP from their inception to August 20, 2020, for literature concerning the combination of glucosamine and chondroitin in knee osteoarthritis treatment. The Cochrane Collaboration's tool for assessing risk of bias and Jadad scale were used to evaluate the risk of bias and quality of literature. The meta-analysis was performed using Review Manager 5.3 software. Results Eight randomized controlled trials (RCTs) were included, including 7 studies in English and 1 study in Chinese. While the number of included papers was quite limited, the number of participants was decent, and quality appraisal result is acceptable. The total number of patients was 3793, with 1067 patients receiving a combination of glucosamine and chondroitin and 2726 patients receiving other treatments. The meta-analysis results revealed the following: (1) Regarding the total Western Ontario and McMaster Universities Arthritis Index (WOMAC) score, compared with the placebo group, the combination group showed a statistically significant advantage [MD= - 12.04 (- 22.33 similar to- 1.75); P=0.02], while the other groups showed no significance. (2) Regarding the VAS score, none of the comparisons showed significance. (3) In the secondary outcomes, except the comparison of JSN between the combination and placebo groups (MD= -0.09 (- 0.18 similar to - 0.00); P=0.04) and the comparison of the WOMAC stiffness score between the combination and CS groups [MD=-4.70 (- 8.57 similar to- 0.83); P=0.02], none of the comparisons showed a significant difference. (4)Safety analysis results show that none of the comparisons have significant differences. Conclusion Our study confirmed that the combination of glucosamine and chondroitin is effective and superior to other treatments in knee osteoarthritis to a certain extent. It is worthwhile to popularize and apply the combination in KOA treatment considering the point of effect, tolerability and economic costs. Additionally, regarding the limited number of studies and uneven trial quality, more high-quality trials are required to investigate the accurate clinical advantages of the combination.