Background: Chondroitin is a gel-forming polysaccharide that theoretically could reach the joint space after ingestion. It is often recommended for use in patients with osteoarthritis pain as a disease modulator that could reduce pain without the adverse effects of analgesics and nonsteroidal anti-inflammatory drugs. Early studies, including a previous meta-analysis, showed improved pain and increased joint space with chondroitin use; however, more recent and larger studies had conflicting results. In an attempt to reconcile the inconsistent data, Reichenbach and colleagues conducted a systematic review to assess the effect of chondroitin on osteoarthritis pain.

The Study: Studies were located through searches of the Cochrane Central Register of Controlled Trials, Medline, EMBASE, CINAHL, conference proceedings, textbooks, reference lists, and four clinical trial registries. Randomized and quasirandomized controlled trials comparing chondroitin with placebo or no treatment in patients with osteoarthritis of the hip or knee were included. Pain reduction was the primary end point, with increased joint space as a secondary outcome.

The authors analyzed the studies by size (either more than or less than 200 participants), use of allocation concealment, placebo control, intention-to-treat analysis, patient blinding, duration of treatment, and funding source. The more recent trials tended to be larger, of higher quality, and included more patients with higher-grade osteoarthritis than earlier published studies. Statistical analyses calculated the magnitude of the effect of chondroitin in each study (while taking into account the disparities in study sizes and designs), as well as the variation in results that could be caused by interstudy heterogeneity.

Results: Of the 1,453 references located, 45 reports representing 22 trials met the inclusion criteria and were included in the meta-analysis. Overall, the meta-analysis showed no benefit to minimal benefit of oral chondroitin in reducing osteoarthritis pain.

Discussion: To date, this study represents the most comprehensive literature review and analysis of chondroitin use. Despite methodologic flaws in some of the component studies (specifically the earlier ones that showed the greatest effects) and a high degree of heterogeneity, the authors recommend against chondroitin use because of a lack of effectiveness, especially in patients with high-grade osteoarthritis. The possibility of a small benefit for those with low-grade osteoarthritis cannot be excluded and may represent an area for future research.