Sawitzke AD, Shi H, Finco MF, et al. The effect of glucosamine and/or chondroitin sulfate on the progression of knee osteoarthritis: A report from the glucosamine/chondroitin arthritis intervention trial. Arthritis Rheum 2008 Sep 29;58(10):3183-3191.
This is a multicenter, double-blind, placebo-controlled study and a part of the Glucosamine/Chondroitin Arthritis intervention Trial (GAIT) involving 572 patients with knee osteoarthritis. Patients were randomized to receive Glucosamine (500 mg, 3 times daily); Chondroitin Sulfate (CS) (400 mg, 3 times daily); combination of Glucosamine and CS; Celecoxib (200 mg daily); or placebo over two years. The primary outcome measure was mean change in loss of joint space width (JSW) from the baseline.
Researchers reported no clinically significant differences in loss of JSW between any treatment and placebo groups. But patients in the Glucosamine group had the least mean loss in JSW, while those in the combination group had the greatest mean loss. This may be due to reduced absorption of Glucosamine when used along with CS.
The limitations of the study include a smaller sample size, short duration of the study and use of radiographs for JSW measurements.
McAlindon TE, et al. Glucosamine and chondroitin for treatment of osteoarthritis: a systematic quality assessment and meta-analysis. JAMA 2000;283:1469-75.
Meta-analysis of 15 RCTs of glucosamine or chondroitin lasting four or more weeks. Studies were given quality scores and showed publication bias. The aggregated effect size for glucosamine was 0.44, which corresponded to moderate effect. Restricting measurement to larger and higher-quality studies diminished the effect size. Nevertheless, some level of efficacy was supported.
Reginster YJ, et al. Long-term effects of glucosamine sulfate on osteoarthritis progression: a randomized, placebo-controlled clinical trial. Lancet 2001;357:251-6.
An RCT of 212 patients with osteoarthritis of the knee. Patients received either oral glucosamine sulfate 1500 mg daily or placebo for three years. Minimum and mean joint-space width of the medial compartment of the tibiofemoral joints were measured after one and three years. Symptoms were scored by WOMAC. Patients in the treatment arm experienced no joint-space narrowing, whereas patients in the control arm experienced mean joint-space loss of 0.31 mm after three years. In an intention-to-treat analysis, patients showed a statistically significant reduction in WOMAC score after three years. Adverse effects were similar to placebo in this study. This large, well-designed study supports the efficacy of glucosamine in retarding the progression of knee osteoarthritis.