Safety and efficacy of Curcumin versus Diclofenac in Knee Osteoarthritis: a randomized open label parallel arm study

Background: To compare the efficacy and safety of curcumin with diclofenac in the treatment of knee osteoarthritis (OA). Methods: In this randomized, open label, parallel, active controlled clinical study, 139 knee OA patients were randomized to receive either curcumin 500 mg (BCM-95®) capsule three times daily or diclofenac 50 mg tablet two times daily for 28 days. Patients underwent assessment at baseline, day 7, day 14 and day 28. Main outcome measure was severity of pain using Visual Analogue Scale (VAS) at day 14 and day 28. Knee injury and osteoarthritis outcome score (KOOS) (at day 14 and day 28), anti-flatulent effect (at day 7), anti-ulcer effect, weight lowering effect, patient and physician’s global assessment of therapy at day 28 were included as secondary outcome measures. Safety after treatment was evaluated by recording adverse events and laboratory investigation. Results: At day 14 and day 28, patients receiving curcumin showed similar improvement in severity of pain and KOOS scale when compared to diclofenac, and the difference was not statistically significant. At day 7, the patients treated with curcumin experienced significantly greater reduction in number of episodes of flatulence compared with diclofenac (p < 0.01). At day 28, weight lowering effect (p < 0.01) and anti-ulcer effect (p < 0.01) of curcumin were observed. None of the patients required H2 blockers in curcumin group and 19 patients required H2 blockers in diclofenac group (0% vs. 28%, respectively; p < 0.01). Adverse effects were significantly less in the curcumin group (13% vs. 38% in diclofenac group; p < 0.01). Patient’s and physician’s global assessment of therapy was similar in both treatment groups. Conclusion: Curcumin has similar efficacy to diclofenac, but demonstrated better tolerance among patients with knee OA. Curcumin can be an alternative treatment option in the patients with knee OA who are intolerant to the side effects of NSAIDS. Trial Registration: ISRCTN, ISRCTN10074826, Registered 21 November 2017 - Retrospectively registered, http://www.isrctn.com/ISRCTN10074826