Acupuncture Shows Little Benefit for Knee Pain

Hinman RS, McCrory P, Pirotta M, et al.Acupuncture for Chronic Knee Pain: A Randomized Clinical Trial. JAMA. (2014) 312:1313-1322. doi:10.1001/jama.2014.12660.

McGlothlin AE, Roger J. Lewis RJ. JAMA Guide to Statistics and Methods: Minimal Clinically Important Difference Defining What Really Matters to Patients. JAMA. (2014) 312:1342-1343. doi:10.1001/jama.2014.13128.

Wang W, Wu S-X. JAMA Patient Page: Treating Pain With Acupuncture. JAMA. 2014 (312):1365. doi:10.1001/jama.2014.12983.

Acupuncture, by needle or laser, has no clinical benefit over placebo for moderate or severe chronic knee pain in patients older than 50 years, according to the study described in the first article above.

Other trials have found that acupuncture has weak or no effects, and the better the trial design, the weaker the effect. This trial has the best design yet for avoiding the placebo effect.

It also distinguishes between a statistically significant difference and a minimum clinically important difference (MCID). An accompanying clinical review and education page (second citation above) describes why patient-centered MCID is key for studies that evaluate patient-reported outcomes, because “the clinical importance of a given change may not be obvious to clinicians selecting treatments.”

The researchers in the study by Hinman et al used a design intended to prevent recruitment bias. Patients who knowingly choose to enter a study of acupuncture, they reason, might be more likely to believe in acupuncture, and may be more susceptible to a placebo effect. So they asked 342 eligible patients to participate in an observational study with no intervention except questionnaires for 1 year, telling them (to avoid deception) that their data would be part of a larger study evaluating undisclosed osteoarthritis treatments.

They randomized the 282 patients who accepted into four groups of 70 or 71 patients each. The control group only answered questionnaires, and did not know that the larger study was about acupuncture. They invited the remaining 211 patients to participate in a study randomizing three groups to needle or laser acupuncture or to sham treatment.

The two primary outcomes were average knee pain on a 0-to-10 scale  and physical function according to the Western Ontario and McMaster Universities Osteoarthritis (WOMAC) Index, both at 12 weeks. Secondary outcomes were pain, function, and other factors at a year.

Acupuncture showed a statistically significant, but not a clinically significant, benefit.

For example, needle acupuncture showed a 1.1-point improvement on the pain scale (P=0.002), and a 3.9-unit improvement on the WOMAC Index (P=0.4). However, the MCID for pain was 1.8 points, so most patients wouldn’t notice a 1.1-point improvement. Similarly, the MCID on the WOMAC Index was 6 units, so most patients wouldn’t notice a 3.9-unit improvement.

A 2012 systematic review found moderate statistically significant improvements in pain with needle acupuncture, but also smaller, statistically significant improvements with sham.

Of the clinical guidelines for acupuncture, the American College of Rheumatology gives it a conditional recommendation, while the Osteoarthritis Research Society International, European League Against Rheumatism, American Academy of Orthopedic Surgeons, and National Institute for Health and Care Excellence give it uncertain or negative recommendations.

An accompanying patient page explains the basics of acupuncture, including the acupuncture points.