Supplements bring relief for knee pain

Although it doesn't appear to do much for patients with mild knee pain from osteoarthritis, those with moderate to severe pain may get relief with a combination of glucosamine and chondroitin sulfate, according to a large study headed by a University of Utah physician and researcher.

Dr. Daniel O. Clegg presents the findings of the 16-center GAIT study (Glucosamine/Chondroitin Arthritis Intervention Trial) to the American College of Rheumatology Annual Scientific Meeting in San Diego today.

Clegg, chief of the Division of Rheumatology at the U. School of Medicine, was principal investigator in the multi-year trial, which included nearly 16,000 patients who had suffered for at least six months with painful knee osteoarthritis that was detectable on X-ray.

The patients were evaluated at the beginning and at weeks 4, 8, 16 and 24.

In a five-treatment-arm protocol, they were each randomly assigned to receive either glucosamine hydrochloride, sodium chondroitin sulfate, a combination of the two supplements, celecobix or a placebo. Participants in all five groups were allowed to take up to 4,000 mg each day of acetaminophen, as well.

They defined whether someone responded or not by whether they found a 20 percent improvement in knee pain by week 24.

Celecobix improved the knee pain, which the researchers had expected. Glucosamine and chondroitin, separately or together, didn't do much overall, Clegg said. But the combination did seem to yield some marked improvements in the category of patients who had moderate to severe knee pain, he says, adding that more study is needed on that.

"That's a hypothesis-generating finding," Clegg says. "We should look at patients with that level of pain in a study powered to answer that question."

"The bottom, bottom line is that celecobix worked," he says. There were no differences among the supplements compared to placebo. But the study was stratified, from patients with mild pain to those with moderate to severe pain, with about 80 percent of the participants in the mild-pain category, so they were able to see the different levels of relief afforded by the treatments within the different pain categories. Within the 20 percent with more troubling pain, those assigned the two supplements did get relief.

"The lack of response in patients with mild pain may be due to a floor effect, limiting ability to detect response," according to the paper Clegg is presenting.