Clinical efficacy and safety of glucosamine, chondroitin sulphate, their combination, celecoxib or placebo taken to treat osteoarthritis of the knee: 2-year results from GAIT.

BACKGROUND: Knee osteoarthritis (OA) is a major cause of pain and functional limitation in older adults, yet longer-term studies of medical treatment of OA are limited. OBJECTIVE: To evaluate the efficacy and safety of glucosamine and chondroitin sulphate (CS), alone or in combination, as well as celecoxib and placebo on painful knee OA over 2 years. METHODS: A 24-month, double-blind, placebo-controlled study, conducted at nine sites in the US ancillary to the Glucosamine/chondroitin Arthritis Intervention Trial, enrolled 662 patients with knee OA who satisfied radiographic criteria (Kellgren/Lawrence grade 2 or 3 changes and baseline joint space width of at least 2 mm). This subset continued to receive their randomised treatment: glucosamine 500 mg three times daily, CS 400 mg three times daily, the combination of glucosamine and CS, celecoxib 200 mg daily, or placebo over 24 months. The primary outcome was a 20% reduction in Western Ontario and McMaster University Osteoarthritis Index (WOMAC) pain over 24 months. Secondary outcomes included an Outcome Measures in Rheumatology/Osteoarthritis Research Society International response and change from baseline in WOMAC pain and function. RESULTS: Compared with placebo, the odds of achieving a 20% reduction in WOMAC pain were celecoxib: 1.21, glucosamine: 1.16, combination glucosamine/CS: 0.83 and CS alone: 0.69, and were not statistically significant. CONCLUSIONS: Over 2 years, no treatment achieved a clinically important difference in WOMAC pain or function as compared with placebo. However, glucosamine and celecoxib showed beneficial but not significant trends. Adverse reactions were similar among treatment groups and serious adverse events were rare for all treatments.

The effect of glucosamine and/or chondroitin sulfate on the progression of knee osteoarthritis: a report from the glucosamine/chondroitin arthritis intervention trial.

OBJECTIVE: Osteoarthritis (OA) of the knee causes significant morbidity and current medical treatment is limited to symptom relief, while therapies able to slow structural damage remain elusive. This study was undertaken to evaluate the effect of glucosamine and chondroitin sulfate (CS), alone or in combination, as well as celecoxib and placebo on progressive loss of joint space width (JSW) in patients with knee OA. METHODS: A 24-month, double-blind, placebo-controlled study, conducted at 9 sites in the United States as part of the Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), enrolled 572 patients with knee OA who satisfied radiographic criteria (Kellgren/Lawrence [K/L] grade 2 or grade 3 changes and JSW of at least 2 mm at baseline). Patients with primarily lateral compartment narrowing at any time point were excluded. Patients who had been randomized to 1 of the 5 groups in the GAIT continued to receive glucosamine 500 mg 3 times daily, CS 400 mg 3 times daily, the combination of glucosamine and CS, celecoxib 200 mg daily, or placebo over 24 months. The minimum medial tibiofemoral JSW was measured at baseline, 12 months, and 24 months. The primary outcome measure was the mean change in JSW from baseline. RESULTS: The mean JSW loss at 2 years in knees with OA in the placebo group, adjusted for design and clinical factors, was 0.166 mm. No statistically significant difference in mean JSW loss was observed in any treatment group compared with the placebo group. Treatment effects on K/L grade 2 knees, but not on K/L grade 3 knees, showed a trend toward improvement relative to the placebo group. The power of the study was diminished by the limited sample size, variance of JSW measurement, and a smaller than expected loss in JSW. CONCLUSION: At 2 years, no treatment achieved a predefined threshold of clinically important difference in JSW loss as compared with placebo. However, knees with K/L grade 2 radiographic OA appeared to have the greatest potential for modification by these treatments.