Efficacy and safety of glucosamine, diacerein, and NSAIDs in osteoarthritis knee: a systematic review and network meta-analysis

BACKGROUND: To conduct a systematic review and network meta-analysis of randomized controlled trials (RCTs) with the aims of comparing relevant clinical outcomes (that is, visual analog scores (VAS), total and sub-Western Ontario and McMaster Universities Osteoarthritis index (WOMAC) scores, Lequesne algofunctional index, joint space width change, and adverse events) between diacerein, glucosamine, and placebo. METHODS: Medline and Scopus databases were searched from inception to 29 August 2014, using PubMed and Scopus search engines and included RCTs or quasi-experimental designs comparing clinical outcomes between treatments. Data were extracted from original studies. A network meta-analysis was performed by applying weight regression for continuous outcomes and a mixed-effect Poisson regression for dichotomous outcomes. RESULTS: Thirty-one of 505 identified studies were eligible. Compared to placebo, glucosamine showed a significant improvement with unstandardized mean differences (UMD) in total WOMAC, pain WOMAC, function WOMAC, and Lequesne score of −2.49 (95% confidence interval (CI) −4.14, −0.83), −0.75 (95% CI: −1.18, −0.32), −4.78 (95% CI: −5.96, −3.59), and −1.03 (95% CI: −1.34, −0.72), respectively. Diacerein clinically improves visual analog scores, function WOMAC, and stiffness WOMAC with UMD values of −2.23 (95% CI: −2.82, −1.64), −6.64 (95% CI: −10.50, −2.78), and −0.68 (95% CI: −1.20, −0.16) when compared to placebo. CONCLUSIONS: The network meta-analysis suggests that diacerein and glucosamine are equally efficacious for symptom relief in knee OA, but that the former has more side effects. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s40001-015-0115-7) contains supplementary material, which is available to authorized users.