Arthritis Supplements in Question
Glucosamine and Chondroitin No Better Than Placebo for Mild Pain
Supplements vs. Placebo
The Glucosamine/chondroitin Arthritis Intervention (GAIT) trial was designed to determine if the supplements effectively treat the pain associated with osteoarthritis of the knee.
A total of 1,583 people over the age of 40 with confirmed osteoarthritis were randomly placed into five different groups. Each group took either glucosamine, chondroitin sulfate, both the supplements, the Cox-2 anti-inflammatory pain reliever Celebrex, or a placebo.
The study endpoint was a 20% or greater reduction in pain, as determined by a standardized questionnaire, after six months of treatment.
Overall, there was no significant difference in pain reduction between the people using supplements either alone or combined or those taking placebo. There was a greater improved response in the people taking Celebrex.
In the 354 patients with moderate to severe pain, however, the supplement combination appeared to be more effective than either Celebrex or placebo. The researchers say a larger study of patients with moderate to severe pain is needed to better understand the findings.
Another important unanswered question is whether the supplements can slow progression of knee osteoarthritis. Clegg and colleagues will attempt to answer this question by following about half of the original study participants who will continue taking the treatments for two years. Results from that trial are expected in about a year.
In the meantime, Clegg says that patients who want to take the supplements should probably take them in combination for just long enough to determine if they help relieve the pain.
Although few side effects were reported in the six-month study, National Center for Complementary and Alternative Medicine director Stephen Straus, MD, says the long-term safety of the supplements is unknown.
"We've learned from past studies that much longer exposures to certain medications are needed to reveal their true safety profile," he says.
Clegg also warned that the unregulated glucosamine and chondroitin products available commercially may be very different from the supplements used in the study.
Marc C. Hochberg, MD, MPH, who heads the division of rheumatology at the University of Maryland School of Medicine, says the findings also raise interesting questions about the placebo effect.