Editorial, Trade Groups Offer Perspective On Null Chondroitin Meta-Analysis
Patients should continue taking chondroitin sulfate for osteoarthritis if they perceive a benefit, despite a recent study that found a null effect, according to an accompanying editorial in the April 17 Annals of Internal Medicine.
"If patients say that they benefit from chondroitin, I see no harm in encouraging them to continue taking it as long as they perceive a benefit," David T. Felson, M.D., Boston University, says, citing the absence of reported “frequent or severe adverse effects” associated with the ingredient.

However, “the best evidence suggests that chondroitin does not work. I do not encourage anyone to start it,” Felson adds in an Annals of Internal Medicine press release.

Felson’s editorial accompanies a study that found “no robust evidence supports the use of chondroitin in osteoarthritis” and discourages its use.

Stephan Reichenbach, M.D., University of Bern, Switzerland, et al., conducted a meta-analysis of 20 randomized clinical trials involving 4,056 patients. Each trial included patients with osteoarthritis of the knee, hip or both.

The dosages of chondroitin ranged from 800 mg/d to 2,000 mg/d. Treatment durations ranged from six to 103 weeks. The primary endpoint was pain at the end of the trial, and a secondary endpoint was changes in minimum and mean radiographic joint space.

“The meta-analysis of differences in changes between chondroitin and placebo groups revealed a small effect in favor of chondroitin: 0.16 mm on minimum joint space width and 0.23 mm on mean joint space width,” the researchers say. “This corresponds to small effect sizes.”

Reichenbach et al. note a high level of heterogeneity among the trials, which the researchers say made the interpretation of results difficult.

The researchers also did a restricted analysis of three trials that “seemed to have been analyzed according to the intention-to-treat principle.”

“When we pooled the three trials with large sample sizes and an intention-to-treat analysis, 40 percent of randomly assigned patients were included, which resulted in an effect size near zero,” they conclude.

By including only three studies, Reichenbach et al. “excluded the majority of the data” to reach their conclusion that the symptomatic benefit (pain reduction) of chondroitin is “minimal or nonexistent,” the Council for Responsible Nutrition’s Vice President, Scientific and Regulatory Affairs, Andrew Shao, Ph.D., says in a release.

“With over 21 million osteoarthritis sufferers in the U.S. alone, a conclusion based on only three studies hardly seems representative of the population in question,” Shao says.

The Natural Products Association also found fault with Reichenbach et al.’s study. The study made no distinction between mild, moderate and severe osteoarthritis, “which all involve very different treatment regimens,” NPA says.

The trade group cites the Glucosamine/chondroitin Arthritis Intervention Trial as evidence, noting that the GAIT study found participants with moderate-tosevere osteoarthritis experienced significant pain reduction when taking a glucosamine/chondroitin supplement (“The Tan Sheet” Feb. 27, 2006, p. 5).

CRN says previous study results on chondroitin, glucosamine or a combination of the two have been mixed. “However, when the entire body of research for glucosamine and chondroitin is reviewed, the majority of individual studies show benefit to some degree,” CRN says.

NPA Vice President of Scientific and Regulatory Affairs Daniel Fabricant, Ph.D., points out, “It’s important to keep in mind that most consumers use a combination of glucosamine and chondroitin, not just chondroitin by itself.”

It is also important to keep in mind that chondroitin sulfate is a long-term anti-inflammatory not a fastacting analgesic, said Josep Verges, M.D., Ph.D., Spain-based ingredient firm Bioiberica’s scientific director and a clinical pharmacist at the University of Madrid.

Shao says, “As much as we would like for science to always give us clear answers in black and white, the fact is, science is open to interpretation.”

Separately, a recent ConsumerLab report found some joint supplements do not contain the amount of chondroitin stated on the label (see related story p. 4). – Rebekah Moan (r.moan@elsevier.com)




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