Sunday, October 18, 2009

Magnets, Copper Bracelets Useless for Pain Relief

New research indicates that copper bracelets and magnetic wrist straps are ineffective in relieving arthritis pain. The investigators claim that reported pain-relieving benefits of such devices are most likely due only to placebo effects; however, maybe that is a worthwhile reason for using them?

The study conducted in the United Kingdom and appearing in the British journal Complementary Therapies in Medicine [Richmond et al. 2009] enrolled 45 patients aged 50 or over and diagnosed with osteoarthritis. Each participant wore 4 devices in random order during a 16-week period: two wrist straps with differing levels of magnetism, a copper bracelet, and a demagnetized wrist strap (placebo control). Outcome assessments were done using the WOMAC Osteoarthritis Index, the McGill Pain Questionnaire, a pain visual analogue scale (VAS), and medication use.

No differences were observed between devices in terms of their effects on pain, stiffness, physical function, or medication use as measured by any of the assessments. The investigators conclude that magnets and copper bracelets are generally ineffective, and any reported therapeutic benefits are most likely attributable to non-specific placebo effects. On the other hand, they do concede that such devices have no major adverse effects and may provide hope of relief for some patients. According to lead investigator Stewart Richmond, a Research Fellow in the Department of Health Sciences at the University of York, magnet therapy for arthritis is a rapidly growing industry, with annual worldwide sales of devices incorporating permanent magnets worth up to $4 billion USD. “Although their use is generally harmless, people with osteoarthritis should be especially cautious about spending large sums of money on these devices,” he said.

Clinical Comment: It should be noted that this sort of research trial design — with the same subjects crossing over to participate in all 4 therapies — has limitations in terms of producing robust and valid results. Also, the researchers enrolled insufficient numbers of subjects to significantly detect less than at least a 25% therapeutic difference between groups [see our blogpost of 9/25/09 discussing why size matters in research trials]. While the conclusion of this trial is that copper bracelets and magnetic wrist straps exert at best only placebo analgesic effects, we have noted in recent blogposts that placebo effects appear to engender significant pain relief for some persons [see 10/16/09 and 10/7/09]. So, perhaps these devices are not necessarily a bad idea if patients want to wear them — provided only modest cost is involved and the individuals truly believe that the devices could be of benefit. Practitioners, themselves, may be reasonably reluctant to recommend such devices for treating painful arthritis until valid evidence of their effectiveness becomes available. What do you think? (Comment below.)

Reference: Richmond SJ, Brown SR, Campion PD, et al. Therapeutic effects of magnetic and copper bracelets in osteoarthritis: A randomised placebo-controlled crossover trial. Compl Ther Med. Article in Press, October 2009 [abstract here].