Glucosamine, chondroitin fail in knee OA trial: the two dietary supplements did not curb pain in the initial GAIT study and will be tested further.(Clinical Rounds)

The dietary supplements glucosamine HCl and chondroitin sulfate failed to show overall efficacy for pain relief in osteoarthritis of the knee in a large double-blind trial, but questions concerning their potential benefits in patients with more severe pain remain, as do suggestions that longer term use may have disease-modifying effects.

The Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT) randomized 1,583 patients with symptomatic osteoarthritis to receive 1,500 mg/day of glucosamine HCl, 1,200 mg/day of chondroitin sulfate, a combination of the two supplements in those same doses, 200 mg/day of celecoxib, or placebo for 3 months.

The primary outcome measure was response to treatment, which was defined as a 20% decrease in the pain subscale of the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) from baseline at 24 weeks.

Rates of response among patients taking the supplements did not differ significantly from rates of response among patients receiving placebo.

The rate of patient response to glucosamine was 3.9 percentage points higher than placebo, while chondroitin sulfate was 5.3 percentage points higher and the combination was 6.5 percentage points higher.

In comparison, the rate of response to the active comparator celecoxib, at 10 percentage points above placebo, was statistically significant (N. Engl. J. Med. 2006;354:795-808).

A secondary outcome measure was response according to criteria established by the Outcome Measures in Rheumatology Clinical Trials (OMERACT) and Osteoarthritis Research Society International (OARSI) task force, which includes changes in pain, function, and patient's global assessment.