Efficacy and Safety of Turmeric Extracts for the Treatment of Knee Osteoarthritis: a Systematic Review and Meta-analysis of Randomised Controlled Trials.

Sixteen RCTs of up to 16 weeks duration including 1810 adults with knee OA were included. Eleven RCTs compared the efficacy of turmeric extracts with placebo and five with active comparators (NSAIDs). The overall risk bias of included RCTs was moderate. Turmeric extracts significantly reduced knee pain (SMD - 0.82, 95% CI - 1.17 to - 0.47, I2 = 86.23%) and improved physical function (SMD - 0.75, 95% CI - 1.18 to - 0.33, I2 = 90.05%) compared to placebo but had similar effects compared to NSAIDs. BMI was the major contributor to heterogeneity in the placebo-controlled studies (explained 37.68% and 67.24%, respectively, in the models) and modified the effects of the turmeric on pain and physical function with less improvement with higher BMI (SMD 0.26 95% CI 0.04 to 0.48; SMD 0.48 95% CI 0.21 to 0.74). No significant between-group differences were reported for either biochemical markers or imaging outcomes. Turmeric extracts had 12% fewer adverse events than NSAIDs and similar rates to placebo. Turmeric extract is a safe and effective option for the symptomatic management of knee OA, compared to placebo or NSAIDs. However, current evidence from short-term studies is heterogeneous and has moderate risk of bias leading to some uncertainty about the true effect.