February 2006

Study shows glucosamine efficacy

Glucosamine and chondroitin provide significant relief to osteoarthritis sufferers with moderate to severe pain, according to a study published in the New England Journal of Medicine. However, the popular dietary supplement combination did not provide significant relief from osteoarthritis pain among all participants.

Researchers conducted the four-year study known as the Glucosamine/chondroitin Arthritis Intervention Trial (GAIT) at 16 sites across the United States.

GAIT enrolled nearly 1,600 participants which were randomly assigned to receive one of five treatments daily for 24 weeks: glucosamine alone (1500 mg), chondroitin sulfate alone (1200 mg), glucosamine and chondroitin sulfate combined (same doses), a placebo, or celecoxib (200 mg).

Celecoxib is an FDA-approved drug used for the management of osteoarthritis pain. It served as a positive control for the study. (A positive control is a treatment that investigators expect participants to respond to in a predictable way; it helps validate study results.) A positive response to treatment was defined as a 20 percent or greater reduction in pain at week 24 compared to the start of the study.

The researchers found that participants taking celecoxib experienced statistically significant pain relief, as expected, versus placebo — about 70 percent of those taking celecoxib versus 60 percent taking placebo had a 20 percent or greater pain reduction.

For all participants, there were no significant differences between the other treatments tested and placebo.

However, for participants in the moderate-to-severe pain subgroup, glucosamine combined with chondroitin sulfate provided statistically significant pain relief compared to placebo — about 79 percent in this group had a 20 percent or greater pain reduction compared to 54 percent for placebo. In the subgroup of participants with mild pain, glucosamine and chondroitin sulfate together or alone did not provide statistically significant relief compared to placebo.

The GAIT team continues its research with a smaller study to see whether glucosamine and chondroitin sulfate can alter the progression of osteoarthritis, such as delaying the narrowing of the joint spaces. About one-half of the participants in the larger GAIT study were eligible to enroll in this ancillary study. The results are expected in about a year.

Source: EurekAlert, www.eurekalert.org

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