Glucosamine and Chondroitin Do Work in Osteoarthritis

A couple of months ago, researchers published the latest findings of the Glucosamine/Chondroitin Arthritis Intervention Trial (GAIT), a study that compared these natural building blocks of knee cartilage against the drug Celebrex and placebos. Based on 
x-rays of the subjects’ knees, the researchers concluded that none of the treatment groups fared any better than the placebo group, according to their report in Arthritis & Rheumatism.

A valid study? It helps to track the history of the GAIT study.

In 2006, the researchers reported how the different treatments affected symptoms of knee osteoarthritis after just six months. At the time, they wrote that there was no reduction in pain or swelling. But the study actually showed that people with the most pain had significant benefits from a combination of glucosamine and chondroitin supplements. In fact, these supplements led to greater pain relief than with the drug Celebrex. No conclusions could be drawn from people with mild osteoarthritic pain because such cases are difficult to assess.

In the latest GAIT report, the researchers acknowledged numerous problems with their data: the progression of osteoarthritis among people taking placebos was less than half of what had been anticipated. That alone would have skewed all data from the study, yet the researchers still argued that glucosamine and chondroitin were of no value.

My friend Jason Theodosakis, MD, author of The Arthritis Cure, told me that the study had three methodological problems – fatal flaws, if you will. First, the number of subjects remaining in the study was too small to achieve statistical significance. Second, the study ran for only two years, whereas other studies have shown that three years is the minimum time needed to demonstrate regeneration of knee cartilage. Third, the x-ray instruments used to measure joint-cartilage deterioration or growth was not sophisticated enough to make clinically meaningful measurements.

Despite all of these limitations, glucosamine hydrochloride supplements did lead to an improvement in joint cartilage compared with all of the other treatments. Inexplicably, however, people taking a combination of glucosamine and chondroitin experienced the greatest progression of joint damage. (I’m guessing, but it is conceivable that the patients taking glucosamine and chondroitin had such a great reduction in pain that they became too active physically, and in the process they injured their tender joints.)

Meanwhile, a separate article by the same researchers, published in Osteoarthritis and Cartilage, found that people taking chondroitin supplements benefited from substantial reductions in joint swelling. Essentially, the researchers published positive findings in one journal and negative findings in another journal. My head was left spinning.