Author Affiliation: The Arthritis Center, Boston University School of Medicine, Boston, Mass.
Context Glucosamine and chondroitin preparations are widely touted in the lay
press as remedies for osteoarthritis (OA), but uncertainty about their efficacy
exists among the medical community.
Objective To evaluate benefit of glucosamine and chondroitin preparations for
OA symptoms using meta-analysis combined with systematic quality assessment
of clinical trials of these preparations in knee and/or hip OA.
Data Sources We searched for human clinical trials in MEDLINE (1966 to June 1999)
and the Cochrane Controlled Trials Register using the terms osteoarthritis, osteoarthrosis, degenerative arthritis, glucosamine, chondroitin, and glycosaminoglycans.
We also manually searched review articles, manuscripts, and supplements from
rheumatology and OA journals and sought unpublished data by contacting content
experts, study authors, and manufacturers of glucosamine or chondroitin.
Study Selection Studies were included if they were published or unpublished double-blind,
randomized, placebo-controlled trials of 4 or more weeks' duration that tested
glucosamine or chondroitin for knee or hip OA and reported extractable data
on the effect of treatment on symptoms. Fifteen of 37 studies were included
in the analysis.
Data Extraction Reviewers performed data extraction and scored each trial using a quality
assessment instrument. We computed an effect size from the intergroup difference
in mean outcome values at trial end, divided by the SD of the outcome value
in the placebo group (0.2, small effect; 0.5, moderate; 0.8, large), and applied
a correction factor to reduce bias. We tested for trial heterogeneity and
publication bias and stratified for trial quality and size. We pooled effect
sizes using a random effects model.
Data Synthesis Quality scores ranged from 12.3% to 55.4% of the maximum, with a mean
(SD) of 35.5% (12%). Only 1 study described adequate allocation concealment
and 2 reported an intent-to-treat analysis. Most were supported or performed
by a manufacturer. Funnel plots showed significant asymmetry (P≤.01) compatible with publication bias. Tests for heterogeneity
were nonsignificant after removing 1 outlier trial. The aggregated effect
sizes were 0.44 (95% confidence interval [CI], 0.24-0.64) for glucosamine
and 0.78 (95% CI, 0.60-0.95) for chondroitin, but they were diminished when
only high-quality or large trials were considered. The effect sizes were relatively
consistent for pain and functional outcomes.
Conclusions Trials of glucosamine and chondroitin preparations for OA symptoms demonstrate
moderate to large effects, but quality issues and likely publication bias
suggest that these effects are exaggerated. Nevertheless, some degree of efficacy
appears probable for these preparations.
McAlindon TE, LaValley MP, Gulin JP, Felson DT. Glucosamine and Chondroitin for Treatment of OsteoarthritisA Systematic Quality Assessment and Meta-analysis. JAMA. 2000;283(11):1469-1475. doi:10.1001/jama.283.11.1469