Thitinan Srikulmontree, MD, a rheumatologist who read both articles but was unaffiliated with either study, says, “chondroitin sulfate may have some positive effects in MRI changes of knee OA, but did not result in improvement in patient symptoms. A larger study with longer duration may help clarify its clinical significance.”
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A rheumatologist with Mercy Medical Group in Rocklin, Calif., Dr. Srikulmontree, author of the ACR patient fact sheet on OA, notes that the article in Annals was NIH-funded and industry independent. Additionally, it was “the first to look at the effects of CS in knee OA using quantitative MRI, which is a very sensitive imaging technique for evaluating the musculoskeletal structures.” On the other hand, the study had a “relatively small number of participants, [and] the characteristics of subjects showed the patients in a placebo group are quite significantly older, about five years on average. This could affect the outcome.”
Why the divergent results between the Annals and BMJ studies? Dr. Srikulmontree says it may be the small number of patients (69 versus more than 200), the different imaging methodology (MRI versus plain films), and the addition of older patients in the placebo group at baseline. Further research and larger studies may shed more light on efficacy of chondroitin sulphate for OA.
Sue Pondrom is a medical journalist based in San Diego.
1. Wildi LM, Raynauld JP, Martel-Pelletier J, et al. Chondroitin sulphate reduces both cartilage volume loss and bone marrow lesions in knee osteoarthritis patients starting as early as 6 months after initiation of therapy: A randomised, double-blind, placebo-controlled pilot study using MRI. Ann Rheum Dis. 2011;70:982-929.