Thursday, July 8, 2010

Glucosamine of No Help for Chronic Low Back Pain?

Back PainA newly reported clinical trial found that glucosamine was no better than a sugar pill for patients with chronic low back pain (LBP) and degenerative lumbar osteoarthritis (OA). During 6 months of therapy, glucosamine was comparable to placebo on measures of pain-related disability, low back and leg pain, and health-related quality of life, according to the report in the July 7, 2010 issue of the Journal of the American Medical Association (JAMA). However, both DID provide some benefits.

Glucosamine — a natural precursor of bone cartilage and made commercially from the exoskeletons of sea creatures — is widely used as a treatment for OA, despite controversial and conflicting evidence in the past for its benefits, and it is also increasingly taken by patients with LBP. Researchers in Norway investigated the effectiveness of 6-months of therapy with oral glucosamine sulfate (1,500 mg/day) compared with placebo in reducing pain-related disability in 250 patients >25 years of age with chronic LBP (for longer than 6 months) and degenerative lumbar OA. This was a well-designed randomized, controlled trial with adequate power (n=125/group) to detect any significant benefits of glucosamine.

At the beginning of the trial, the average score on the Roland Morris Disability Questionnaire (RMDQ) was 9.2 for the glucosamine group and 9.7 for the placebo group. The 6-month average RMDQ score was 5.0 for both the glucosamine and placebo groups, and 1-year scores were 4.8 for the glucosamine group and 5.5 for the placebo group. No statistically significant differences between the two groups were observed at 6-months or at 1-year for the RMDQ, or for measures of back pain at rest and during activity, or in quality-of-life measures. Mild adverse events were reported in 40 patients in the glucosamine group and 46 patients in the placebo group, primarily self-limiting gastrointestinal symptoms or minor skin problems. There were only 4 discontinuations due to side effects among glucosamine users and 5 in the placebo group.

COMMENTARY: Based on these trial results it seems that glucosamine is well-tolerated and causes minimal toxicity, but the authors conclude that it appears unwise to recommend glucosamine to patients with chronic LBP and degenerative lumbar OA. A most interesting aspect of this trial, not commented on in the published report, is that while glucosamine was no better than placebo, BOTH glucosamine and placebo actually did confer comparable beneficial effects — eg, lowering RMDQ scores — at 6 months, which persisted at 1 year. If anything, this study is an excellent portrayal of the frustrations in treating nonspecific chronic back conditions and the powers of placebo in pain management, which we previously discussed [here]. However, there may have been a confounding effect in this study, since most subjects in both groups were using concomitant analgesics, other therapies, or both during the trial. Still, it would seem inappropriate, perhaps unethical, to recommend glucosamine for chronic back pain merely in anticipation that it would produce a beneficial placebo effect or somehow augment concomitant therapies.

Glucosamine is often paired with chondroitin, another agent that occurs naturally in the body. Chondroitin is believed to help keep cartilage healthy by absorbing fluid into the connective tissue, and it allegedly may block enzymes that break down cartilage and it may provide building blocks for the body to produce new cartilage. However, as with glucosamine, there have generally been unfavorable results in studies of chondroitin and/or the glucosamine-chondroitin combination for various musculoskeletal pain conditions — as we have previously noted in research UPDATES [here], [here], and [here] for example.

REFERENCE: Wilkens P, Scheel IB, Grundnes O, Hellum C, Storheim K. Effect of Glucosamine on Pain-Related Disability in Patients With Chronic Low Back Pain and Degenerative Lumbar Osteoarthritis: A Randomized Controlled Trial. JAMA. 2010;304(1):45-52 [abstract here].