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

Abstract

Purpose of the Review: Finding appropriate pharmacological options to treat osteoarthritis (OA) remains challenging. We aimed to determine the efficacy and safety of all types of turmeric extracts for the management of knee OA.Recent Findings: 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, I 2 =86.23%) and improved physical function (SMD -0.75, 95% CI -1.18 to -0.33, I 2 =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.Summary: 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.

An Investigation into the Effects of a Curcumin Extract (Curcugen®) on Osteoarthritis Pain of the Knee: A Randomised, Double-Blind, Placebo-Controlled Study

“…Several of the findings in this study are consistent with previous trials examining the efficacy of curcumin for knee OA. In a recent meta-analysis, it was confirmed based on findings from 16 randomised controlled trials and 1810 adults, curcumin/turmeric extracts significantly reduced self-reported measures of knee pain (effect size = −0.82) and improved self-reported physical function (effect size = −0.75) compared to the placebo, and had similar treatment efficacy as NSAIDs [ 13 ]. We observed similar reductions in pain ratings, albeit with a lower effect size, but no change in self-report measures of physical function.…”

“…Randomised controlled trials conducted in Asia were associated with significantly-larger treatment effects compared to those conducted in other countries. Wang et al [ 13 ] concluded that lower BMI, and to a lesser extent, younger age, are associated with greater treatment efficacy from curcumin. However, the age and BMI of participants in this study were similar to the previously conducted trials.…”

“…As a treatment for OA, there have been several trials that demonstrate it may reduce pain and increase function in OA sufferers. In two recent meta-analyses, it was confirmed that curcumin and turmeric extracts may be effective for the treatment of knee OA, with minimal adverse effects [ 12 , 13 ]. However, most of these studies have not included functional assessments and many have been evaluated as having a high risk of bias leading to some uncertainty about the true effect of curcumin for the treatment of knee OA [ 13 ].…”

“…In two recent meta-analyses, it was confirmed that curcumin and turmeric extracts may be effective for the treatment of knee OA, with minimal adverse effects [ 12 , 13 ]. However, most of these studies have not included functional assessments and many have been evaluated as having a high risk of bias leading to some uncertainty about the true effect of curcumin for the treatment of knee OA [ 13 ]. The aims of this study were to examine the pain-relieving and functional effects of a curcumin extract (Curcugen ® ) using validated self-report and objective performance-based functional assessments.…”

Considerations to Be Taken When Carrying Out Medicinal Plant Research—What We Learn from an Insight into the IC50 Values, Bioavailability and Clinical Efficacy of Exemplary Anti-Inflammatory Herbal Components

“…The largest number of patients was included in randomized clinical trials (RCT) addressing the effect of curcumin on knee osteoarthritis [67,68]. In contrast only one pilot RCT carried out by Chandran et Goel [69] assessed the efficacy of curcumin in rheumatoid arthritis in the frame of a three-armed study comparing the effect of 500 mg curcumin with 50 mg diclofenac each taken two times a day and in combination for eight weeks.…”