Wang Z, Jones G, Winzenberg T, et al. Effectiveness of Curcuma longa Extract for the Treatment of Symptoms and Effusion-Synovitis of Knee Osteoarthritis : A Randomized Trial. Ann Intern Med. 2020 Sep 15. doi: 10.7326/M20-0990. (Original study)

BACKGROUND: Current pharmacologic therapies for patients with osteoarthritis are suboptimal.

OBJECTIVE: To determine the efficacy of Curcuma longa extract (CL) for reducing knee symptoms and effusion-synovitis in patients with symptomatic knee osteoarthritis and knee effusion-synovitis.

DESIGN: Randomized, double-blind, placebo-controlled trial. (Australian New Zealand Clinical Trials Registry: ACTRN12618000080224).

SETTING: Single-center study with patients from southern Tasmania, Australia.

PARTICIPANTS: 70 participants with symptomatic knee osteoarthritis and ultrasonography-defined effusion-synovitis.

INTERVENTION: 2 capsules of CL (n = 36) or matched placebo (n = 34) per day for 12 weeks.

MEASUREMENTS: The 2 primary outcomes were changes in knee pain on a visual analogue scale (VAS) and effusion-synovitis volume on magnetic resonance imaging (MRI). The key secondary outcomes were change in Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain and cartilage composition values. Outcomes were assessed over 12 weeks.

RESULTS: CL improved VAS pain compared with placebo by -9.1 mm (95% CI, -17.8 to -0.4 mm [P = 0.039]) but did not change effusion-synovitis volume (3.2 mL [CI, -0.3 to 6.8 mL]). CL also improved WOMAC knee pain (-47.2 mm [CI, -81.2 to -13.2 mm]; P = 0.006) but not lateral femoral cartilage T2 relaxation time (-0.4 ms [CI, -1.1 to 0.3 ms]). The incidence of adverse events was similar in the CL (n = 14 [39%]) and placebo (n = 18 [53%]) groups (P = 0.16); 2 events in the CL group and 5 in the placebo group may have been treatment related.

LIMITATION: Modest sample size and short duration.

CONCLUSION: CL was more effective than placebo for knee pain but did not affect knee effusion-synovitis or cartilage composition. Multicenter trials with larger sample sizes are needed to assess the clinical significance of these findings.

PRIMARY FUNDING SOURCE: University of Tasmania and Natural Remedies Private Limited.

Discipline Area Score
Physician 5 / 7
Comments from MORE raters

Physician rater

This is a single centre double blind placebo controlled trial of Curcumin (Curcumina longa extract) versus placebo in patients with symptomatic OA affecting the knee joint. The main outcome measures were VAS Pain and MRI evidence of effusion and synovitis. There were seventy participants in the trial that was conducted over 12 weeks with a significant improvement in VAS Pain not in the MRI measurements of effusion and synovitis in the Curcumin treated versus the placebo treated patients. There were no significant side effects from Curcumin use in this patient group. While this is a promising study, it involves a small number of patients with a short duration of treatment and follow up in a condition that requires long term treatment for many years. Larger studies of a longer duration are needed to clarify the role of Curcumin in the management of patients with knee OA.

Physician rater

This randomized trial with small simple size and a short duration shows a modest effect on knee OA pain of Curcuma longa Extract, without any effect on structural measures. Even so, this is a valuable study considering the drug tolerabiliy and the present suboptimal pharmacologic options.
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