WHAT’S NEW: Study results leave little room for doubt
This meta-analysis used more sophisticated comparison techniques and used only larger (and probably better quality) studies than previous meta-analyses. However, inclusion and exclusion were not based on any study quality criteria.
The authors found that glucosamine and chondroitin, used alone or in combination, provide little benefit in terms of pain relief of OA of the knee or hip compared with placebo, and contend that we should recommend against patients buying them. This meta-analysis is consistent with the American Academy of Orthopedic Surgeons 2008 guideline for knee OA, which recommends not using glucosamine and/or chondroitin based on good evidence.6
CAVEATS: Rate of joint replacement was not considered
This meta-analysis did not study the effect of these supplements on joint replacement. In a 5-year follow-up study after completion of 2 of the RCTs included in this meta-analysis, the relative risk of total joint replacement was 0.43 (95% CI, 0.2-0.92) for those in the glucosamine group (who had taken 1500 mg glucosamine sulphate for 12-36 months) compared with placebo (NNT=12).7 However, the authors were only able to follow up with 81% of the original participants. In the meta-analysis reported here, the difference in joint space narrowing was unlikely to be clinically significant or to lead to a difference in joint replacement rates.
Among the studies included in the meta-analysis, commercially funded trials had a greater decrease in pain with glucosamine or chondroitin compared with independent trials. This did not change the overall outcome of the meta-analysis, thereby supporting the validity of the results.
CHALLENGES TO IMPLEMENTATION: These supplements are available OTC
There are few barriers to advising patients not to use these products. Since glucosamine and chondroitin are available over-the-counter, however, patients have ready access to them, even if their doctors don’t recommend them. Several meta-analyses have not found an increased risk of harm from these products (other than the expense).1,5
Acknowledgement
The PURLs Surveillance System is supported in part by Grant Number UL1RR024999 from the National Center For Research Resources, a Clinical Translational Science Award to the University of Chicago. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Center For Research Resources or the National Institutes of Health.