Glucosamine, chondroitin not effective for hip or knee osteoarthritis

The popular supplements glucosamine and chondroitin have no effect on pain or joint space narrowing in hip and knee osteoarthritis, according to a new study.

Researchers in the United Kingdom performed a network meta-analysis of 10 trials to determine whether glucosamine, chondroitin or the two combined helped knee or hip pain in osteoarthritis. In the network meta-analysis, the authors wrote, “Direct comparisons within trials were combined with indirect evidence from other trials by using a Bayesian model that allowed the synthesis of multiple time points.” The main outcome measure was pain intensity, while the secondary outcome was change in joint space narrowing. The researchers defined −0.9 cm on a 10-cm visual analogue scale as a clinically important difference between study preparations and placebo. The results were published online Sept. 16 by BMJ.

The 10 included trials involved 3,803 patients, with an average age of 58 to 66 years. A median of 68% of patients were women. The difference in pain intensity for supplements compared with placebo was −0.4 cm (95% credible interval, −0.7 to −0.1 cm) for glucosamine, −0.3 cm (95% credible interval, −0.7 to 0.0 cm) for chondroitin and −0.5 cm (95% credible interval, −0.9 to 0.0 cm) for the combination. Trials funded by industry showed larger supplement effects than trials that were not industry funded (P=0.02). Joint space narrowing differed only minutely between groups.

The authors noted that the included trials measured joint pain with different instruments, which could have affected their results, among other limitations. However, they concluded that chondroitin and glucosamine, while not harmful, do not benefit patients with knee or hip osteoarthritis. “Coverage of costs by health authorities or health insurers for these preparations and novel prescriptions to patients who have not received other treatments should be discouraged,” they wrote.