Efficacy of Curcuma longa in relieving pain symptoms of knee osteoarthritis patients: a systematic review and meta-analysis of clinical trials

Abstract

Objective: Osteoarthritis (OA), particularly knee OA, affects 24% of adults and is a significant cause of disability. Nonsteroidal anti-inflammatory drugs (NSAIDs) are commonly used but have many adverse effects. Antioxidant and anti-iflammatory properties of Curcuma longa might decrease pain thus improving joint function.

Methods: This systematic review and meta-analysis evaluated randomized controlled trials (RCTs) on Curcuma longa efficacy for knee OA. We reported mean differences (MD) with 95% confidence interval (CI) for continuous outcomes and evaluated Visual Analog Scale (VAS) for pain and the Western Ontario and McMaster Universities Arthritis Index (WOMAC) total score over 4 to 6 weeks for treatment effects.

Results: Ten RCTs with 786 patients were included. Curcuma longa significantly improved VAS for pain than placebo (MD 18.25, 95% CI 7.79 to 28.72, p=0.0006). It was not inferior to NSAIDs in WOMAC total score improvement (MD -11.99, 95% CI -39.21 to 15.23, p=0.39). Both dosages (<1,000 and ≥1,000 mg/day) of Curcuma longa demonstrated similar improvement in VAS for pain compared to placebo (MD 27.02, 95% CI 1.45 to 52.60, p=0.04; MD 21.48, 95% CI 1.78 to 41.18, p=0.03).

Conclusion: Curcuma longa benefits knee OA pain and function, being more effective than placebo and comparable to NSAIDs. Despite positive results, limitation and heterogeneity of the studies necessitates further research to explore optimal dosages and administration methods of Curcuma longa as therapeutic option for knee OA.

Keywords: Curcuma; Knee osteoarthritis; Visual Analog Scale; Western Ontario and McMaster Universities Arthritis Index.

Figure 1

Flowchart of identification and screening process for eligible randomized controlled trials.

Figure 2

Detailed risk of bias among included randomized controlled trials.

Figure 3

Forest plot portraying VAS for pain. SD: standard deviation, IV: interval variable, CI: confidence interval, VAS: Visual Analog Scale.

Figure 4

Forest plot portraying WOMAC total score of Curcuma longa vs. placebo-controlled group. SD: standard deviation, IV: interval variable, CI: confidence interval, WOMAC: Western Ontario and McMaster Universities Arthritis Index.

Figure 5

Forest plot portraying WOMAC total score of Curcuma longa vs. NSAIDs-controlled group. SD: standard deviation, IV: interval variable, CI: confidence interval, NSAIDs: nonsteroidal anti-inflammatory drugs, WOMAC: Western Ontario and McMaster Universities Arthritis Index.

Figure 6

Funnel plot, left to right of (A) VAS for pain score, (B) WOMAC total score. VAS: Visual Analog Scale, WOMAC: Western Ontario and McMaster Universities Arthritis Index, SE: standard error, MD: mean differences.