Patients and physicians alike are struggling to sift through the
often-conflicting information on glucosamine and chondroitin sulfate use for
relieving osteoarthritis pain.
The most significant contribution to this confusion: A National
Institutes of Health (NIH)-funded study known as the
Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT) which was
presented at the 2005 American College of Rheumatology (ACR) meeting.
In the study abstract, researchers concluded that glucosamine and
chondroitin sulfate effectively treat moderate-to-severe osteoarthritis knee
pain, according to David S. Hungerford, MD, orthopedic surgeon at The Johns
Hopkins University in Baltimore.
David S. Hungerford
From the podium, however
[the studys principal
author, Daniel O. Clegg, MD] concluded, Glucosamine and chondroitin
sulfate are no better than placebo, Hungerford told colleagues at
the 7th Annual Current Concepts in Joint Replacement Spring 2006 Meeting.
The contradictions did not stop there. This has led to a lot of
controversy in the lay public, with articles in the New York Times
saying that the GAIT study shows no significant effect of nutraceuticals, and
then Clegg appearing in a post-ACR meeting saying that there was some
significance. So, its confusing, Hungerford said.
Hungerford said that the GAIT study contradictions might be related to a
variation in evaluation methods, including the WOMAC Osteoarthritis Index and
the Outcome Measures in Rheumatology (OMERACT) score.
The GAIT study, a five-arm multicenter study beginning in 1999, enrolled
roughly 1,500 patients. Researchers randomized patients to receive glucosamine
alone, chondroitin sulfate alone, combined glucosamine and chondroitin sulfate,
Celebrex, or placebo.
Among patients with a WOMAC pain score of 125 mm to 300 mm, those taking
Celebrex reported the only statistically significant improvement
But with a WOMAC pain score [of 301 mm to 400 mm], the combination
of glucosamine and chondroitin sulfate (79.2%) is statistically significant
(P=.002), and Celebrex, interestingly enough, is not statistically
significant in this group, Hungerford said.
No response in mild pain group
Although the researchers found that glucosamine and chondroitin sulfate
effectively treated moderate-to-severe osteoarthritis, they found no response
in patients with mild pain because of a floor effect that limited
the ability to detect a response, he said.
In patients with
a low WOMAC pain stratum, celecoxib shows significant improvement, while
glucosamine and chondroitin sulfate do not. But the roles are reversed on the
higher pain scale.
Source: Hungerford DS
Overall, the researchers said there was a significant improvement with
Celebrex and not for the combined glucosamine and chondroitin sulfate. However,
the researchers enrolled significantly fewer patients in the moderate-to-severe
group compared to the mild group, Hungerford said.
He also found that the WOMAC score might not be sensitive enough to
detect all changes and requires a 20% improvement for a positive response.
If you look at the OMERACT
[there] was [a] statistically
significant difference for both Celebrex and glucosamine and chondroitin
[sulfate] for the group as a whole, Hungerford said.
Three-month trial recommended
Hungerford has recommended the combined therapy in his practice for 10
years and believes that a three-month trial is the best approach. If a
patient responds, then he or she should continue. If the patient doesnt
respond, you dont continue, he said.
No study has shown negative side effects with glucosamine and
chondroitin sulfate, such as those found with some NSAIDs like Vioxx, he said.
Consequently, [the combination] is a reasonable thing to apply to your
patients, and [its] basically risk-free.
For more information:
- Clegg DO, Reda DJ, Harris CL, et al. Glucosamine, chondroitin
sulfate and the two in combination for painful knee osteoarthritis. N
Engl J Med. 2006;354:795-808.
- Hungerford D. Over-the-counter interventions: What a difference a
decade makes. #65. Presented at the 7th Annual Current Concepts in Joint
Replacement Spring 2006 Meeting. May 21-24, 2006. Las Vegas.