True relief or placebo?

The combination of glucosamine and chondroitin sulfate is about as effective as placebo for most people with osteoarthritis knee pain, according to a major national study headed by a University of Utah researcher.

But a subgroup of clinical trial participants with moderate to severe pain did appear to get significant relief from combining the two supplements, according to the study, published today in the New England Journal of Medicine.

While the number of people in the study who fit that category — only 22 percent — was too small to draw strong conclusions and the study was not designed to answer that question, the finding indicates the need for more research on people in that specific pain range, said Dr. Daniel O. Clegg, professor of medicine at the U. School of Medicine, chief of rheumatology at the George E. Wahlen Veterans Affairs Medical Center and the lead investigator.

Osteoarthritis is the most common form of arthritis, affecting about 21 million Americans, a number expected to double by 2020, Clegg said. A survey in 2002 found about 5.2 million American adults used glucosamine, with or without chondroitin, and that arthritis was one of the major reasons why, added Dr. Stephen E. Straus, director of the National Center for Complementary and Alternative Medicine (NCCAM).

A common symptom of osteoarthritis is progressive pain, associated with premature failure of the cartilage that, when healthy, provides smooth movement. Losing excess body weight, strengthening muscles and getting exercise are all helpful, Clegg said. Pain relievers like acetaminophen and ibuprofen may also provide relief. Severe pain may require prescription pain medicine such as celecoxib and, as the damage progresses, joints may need to be replaced. The dietary supplement combination of glucosamine and chondroitin has been a popular seller among people with arthritis pain, but its ability to provide relief has been anecdotal until this five-year, $12.5 million study.

The GAIT study — Glucosamine/Chondroitin Arthritis Intervention Trial — was conducted at 16 academic rheumatology centers. It compared the effectiveness of the two supplements individually or taken together, against the positive control of the pain reliever celecoxib (it's already approved and pain response to it is predictable) and the negative control of a placebo. Success of a treatment in the study was at least a 20 percent reduction in pain. Both pain and X-ray proof of osteoarthritis were needed to participate.