Acupuncture has a specific effect on chronic pain, superior to both no-acupuncture control and sham acupuncture. A review in JAMA Internal Medicine (formerly Archives of Internal Medicine) of some 18 000 patients finds acupuncture is a reasonable referral option for patients with chronic pain.
The review by first author Dr Andrew J. Vickers, Departments of Epidemiology and Biostatistics, Memorial Sloan-Kettering Cancer Center, New York together with American, British and German colleagues comprises 29 high-quality randomized controlled trials (RCTs) of acupuncture and chronic pain of in all 17922 patients.
Four chronic pain conditions included
The researchers have aimed to determine the effect size of acupuncture for four chronic pain conditions:
Although acupuncture is widely used for chronic pain, its value is still controversial. This is probably in part due both to the lack of a biologically plausible mechanism, and to the fact that it to some extent relies on theories outside of biomedicine.
Weaknesses of prior reviews
Prior reviews have included RCTs of inferior quality, and have then come to the circular conclusion that weaknesses in the data did not allow conclusions to be drawn. Other reviews have not included meta-analyses at all, apparently owing to variation in study end points.
The current review has – the authors argue – avoided both problems by including only high-quality RCTs and obtaining raw data for individual patient data meta-analysis.
Novel finding of specific effect
The finding of the review of a robust difference between acupuncture and sham control, i.e. a specific acupuncture effect, distinguishable from bias, is novel.
In the primary analysis, including all eligible RCTs, acupuncture was superior to both sham and no-acupuncture control for each pain condition (P <.001 for all comparisons). After exclusion of an outlying set of RCTs that strongly favored acupuncture, the effect sizes were similar across pain conditions.
Patients receiving acupuncture had less pain, with scores that were 0.23 (95% CI, 0.13-0.33), 0.16 (95% CI, 0.07-0.25), and 0.15 (95% CI, 0.07-0.24) standard deviations lower than sham controls for back and neck pain, osteoarthritis, and chronic headache, respectively. In other words, the differences in effect size between acupuncture and sham acupunture were quite modest.
Effect sizes in comparison to no-acupuncture controls (placebo) were considerably larger: 0.55 (95% CI, 0.51-0.58), 0.57 (95% CI, 0.50-0.64), and 0.42 (95% CI, 0.37-0.46) standard deviations. These results were robust to a variety of sensitivity analyses, including those related to publication bias.
Clinically and scientifically important
If acupuncture was just a strong placebo, many clinicians might feel uncomfortable in providing it or referring patients. Also, one might well argue that health insurance should not reimburse therapies lacking specific effects.
Hence, the authors characterize their discovery of acupuncture effects over and above those of sham acupuncture as being both clinically and scientifically important.
Even though on average these effects are small, the clinical decision made by physicians and patients should not be between true and sham acupuncture, but between a referral to an acupuncturist or avoiding such a referral.
The most robust evidence to date
The total acupuncture effects which the patient typically experiences is made up of three components:
All in all, the authors conclude, the review provides the most robust evidence to date that acupuncture is a reasonable referral option for patients with chronic pain.
David Finer
References:
Vickers AJ, Cronin AM, Maschino AC, et al. Acupuncture for chronic pain: individual patient data meta-analysis. Archives of Internal Medicine. September 10, 2012.
Report by NCCAM 120910: Acupuncture May Be Helpful for Chronic Pain: A Meta-Analysis.
Tags: acupuncture, back pain, CAM, chronic pain, George Lewith, headache, meta-analysis, neck pain, osteoarthritis, placebo, RCT, sham acupuncture, shoulder pain
