Safety and efficacy of curcumin versus diclofenac in knee osteoarthritis: a randomized open-label parallel-arm study

Shep D, Khanwelkar C, Gade P, Karad S · Trials

VAS pain fell in both arms and finished level at day 28 (2.20 against 2.20; p=0.98), as did all five KOOS subscales. The trial was powered to detect a 1.24-point difference between the arms, so this is a failure to find one rather than demonstrated equivalence — no non-inferiority margin was set. The separation was in tolerability: adverse events 13% against 38% (p<0.01), no patient on curcumin needed an H2 blocker against 19 of 69 on diclofenac (p<0.01), fewer episodes of flatulence by day 7, and a weight-lowering effect at day 28. Patient and physician global assessments of therapy were alike in both arms.

Population

Adults with knee osteoarthritis, India

Intervention

Curcumin 500 mg three times daily for 28 days

Comparator

Diclofenac 50 mg twice daily (no placebo arm)

Limitations

Open-label with no placebo arm — the authors name both — 28 days, single centre, and every efficacy measure is subjective. Powered for superiority rather than equivalence, so matched pain scores do not establish that the two treatments are alike. The paper declares no funding, but the BCM-95 curcumin capsules were supplied by their manufacturer, Arjuna Natural.