McAlindon TE, LaValley MP, Gulin JP, Felson DT. Glucosamine
and chondroitin for treatment of osteoarthritis: a systematic quality
assessment and meta-
analysis. JAMA. 2000 Mar 15;283:
1469-75.
Question: In patients with osteoarthritis, are glucosamine
and chondroitin effective for relieving symptoms and improving function?
Data sources: Studies were identified by searching
MEDLINE (1966 to June 1999) and the Cochrane Controlled Trials Register.
Bibliographies of articles and meeting abstracts published in supplements
of Arthritis and Rheumatism, the British
Journal of Rheumatology, and Osteoarthritis and
Cartilage (1978 to 1998) were searched manually. Authors,
content experts, and drug manufacturers were contacted.
Study selection: Studies in any language were selected
if they were controlled trials that compared oral or parenteral
glucosamine sulfate, glucosamine hydrochloride, or chondroitin sulfate
with placebo for 4 weeks in patients with knee or hip osteoarthritis.
Studies also had to include 1 outcome measure from a list compiled
by the reviewers.
Data extraction: 2 reviewers assessed the quality of
studies (14-item quality scale) and resolved disagreements by discussion.
Data were extracted on patients, the route of administration, the
joint with osteoarthritis, outcomes, funding, allocation concealment,
the use of intention-to-treat analysis, and effect sizes.
Results: 17 studies met the inclusion criteria.
2 of these did not provide sufficient data for extraction and were
excluded from the meta-analysis. The mean quality score was 36%.
No studies reported adequate allocation concealment; only 1 study
used intention-to-treat analysis. No studies reported independent
funding from any governmental or nonprofit organization. 6 studies
of glucosamine, which involved 911 patients, had quality scores ranging
from 12% to 52%. Outcome measures were the Lequesne Index (a questionnaire-based
disability score) (3 studies), global pain scores (2 studies), and
the Western Ontario and McMaster Universities Osteoarthritis Index
score (1 study). Combined results showed a moderate benefit for glucosamine
(effect size, 0.44; 95% CI, 0.24-0.64). Studies of chondroitin,
which involved 799 patients, had quality scores ranging from 14%
to 55%. Outcome measures were the Lequesne Index score (2 studies),
global pain scores (5 studies), mobility scores (1 study), and the
use of nonsteroidal anti-inflammatory drugs (1 study). Chondroitin
had a large benefit (effect size, 0.96; 95% CI, 0.63-1.3), but studies were
heterogeneous (P < 0.001). When the study with the
largest effect size (4.56) was removed, heterogeneity was no longer
significant (effect size, 0.78; 95% CI, 0.60-0.95).
Conclusion: In patients with osteoarthritis, glucosamine
and chondroitin are effective for improving outcomes. However, the
magnitude of effect is unclear because of inconsistencies in study
design and dependence on industry support for study execution.