Glucosamine and Chondroitin for Knee OA
Reaction?
Surprise. Since 1997, use of glucosamine and chondroitin had exploded. The country’s best-selling dietary supplements, which come from animal sources such as crab shells and cow, pig or chicken cartilage, were thought to relieve knee pain and perhaps repair the cells that line the joint, revitalizing worn cartilage. Doctors were skeptical at first, because a few small studies produced conflicting results, but many came to support their patients trying them and some encouraged them to do so. The surprise was followed by disappointment. Had people with arthritis lost a promising treatment?
What you might have missed:
Overall results showed no significant pain relief in those who took the supplements, but closer analysis found something interesting that got lost in the upset: A small subgroup of people with moderate-to-severe pain did get significant pain relief.
Because the study had an imbalance of people with mild pain – there were 20 times more people in the study with mild pain than with moderate-to-severe pain – their experience dominated the results. Lead researcher Daniel O. Clegg, MD, a professor of medicine and chief of the division of rheumatology at the University of Utah School of Medicine in Salt Lake City, says, “While the result was fairly strong among people with moderate-to-severe pain, it affected only 72 [of the 1,583] patients,” which means it’s an area worthy of more study.
Critics of the study point out that people with mild pain would have had difficulty discerning a benefit from the supplements. Those who were in moderate-to-severe pain were more likely to perceive a benefit, if only because they had more room to improve. Roland Moskowitz, MD, professor of medicine at Case Western Reserve University in Cleveland, says GAIT’s overall results may have been different if glucosamine sulfate was used instead of glucosamine hydrochloride.
Results from a European glucosamine trial released at the same time as GAIT’s results showed that glucosamine sulfate effectively controlled pain in people with knee OA. Plus, says Dr. Moskowitz, having the study participants take glucosamine once a day instead of a three times a day would have given a higher peak effect, increasing the odds of significant relief.
Your take-home message:
Other studies of glucosamine plus chondroitin have shown positive effects, and even GAIT showed glimmers of benefit. “We have to say something is going on,” Dr. Moskowitz says. “A three-month trial [of glucosamine and chondroitin] is reasonable for people who have a lot of pain. If it’s working, by all means continue using them, as these supplements are extremely safe,” he says.
Glucosamine/Chondroitin Arthritis Intervention Trial
