Osteoarthritis causes disability and is a major public health problem. A new study examined the effect of chondroitins 4 and 6 sulfate (CS) on osteoarthritis progression and symptoms. CS, unlike other chondroitin sulfate products sold as dietary supplements in the U.S., has been approved as a prescription symptomatic slow acting drug for osteoarthritis in many European countries. The image depicts a model of a healthy knee joint.

Led by Andre Kahan of the University of Paris Descartes in Paris, the randomized, double-blind, placebo-controlled study involved 622 patients with osteoarthritis from France, Belgium, Switzerland, Austria and the U.S. Patients had knee X-rays at the time of enrollment and at 12, 18 and 24 months. The X-rays were evaluated for joint space loss and patients were also assessed for osteoarthritis symptoms and pain.

The results showed that "long-term administration of CS over 2 years can prevent joint structure degradation in patients with knee osteoarthritis," the authors state. Joint space loss was significantly reduced in the CS group, fewer patients had progression of joint space width, and CS reduced pain in those taking it compared to the placebo group. CS was well tolerated and there were no significant differences in the frequency of adverse events between the two groups.

The study showed that there was faster improvement regarding pain during the first year in the CS group compared to the placebo group. This may be due to the fact that all of the patients had pain symptoms, so the effect of CS was more noticeable early on. Since those who took a placebo also had decreased pain in the first year, it may also be due to the natural course of the disease. The authors note that the study involved CS, which is used as a prescription drug and that the results cannot be generalized to other chondroitin sulfate products or compounds, such as those available in the form of dietary supplements.

The decrease in joint space loss shown in this and another recent study involving 300 patients, suggests better outcomes for osteoarthritis patients, according to the authors. They conclude: "Further studies with longer follow-up and different outcome criteria are warranted to assess whether the beneficial structural changes associated with CS demonstrated in our study are predictive of improvement in the long-term clinical progression of osteoarthritis."
References:
1. Andre Kahan, Daniel Uebelhart, Florent De Vathaire, Pierre Delmas, Jean-Yves Reginster. Long-Term Effects of Chondroitins 4 and 6 Sulfate on Knee Osteoarthritis. Arthritis & Rheumatism, February 2009.