Patient characteristics and variation in treatment outcomes: Which patients benefit most from acupuncture for chronic pain?

Abstract

OBJECTIVES The aim of this study was to identify patients' characteristics that increase or decrease their benefit from acupuncture treatment of chronic pain. METHODS Patients with chronic low back pain, headache, neck pain, or pain due to osteoarthritis of the knee or hip, were included in 4 multicenter, randomized, controlled studies, all conducted in Germany. All patients received routine care; the patients randomized to the acupuncture group received additional acupuncture treatment. Data were pooled, and the main outcome was defined as the 3-month change from baseline of the SF-36 bodily pain subscale. To identify predictors for treatment effects and effect modifiers (ie, variables that interact with the form of treatment), patients' characteristics and their interaction with treatment were included in a mixed linear model to predict treatment outcome. RESULTS A total of 9,990 patients who were treated by 2,781 physicians were analyzed. The outcome was markedly improved in the acupuncture group (P < 0.001). Age, education, duration of illness, baseline pain, and some concomitant diseases predicted treatment outcome in both groups. Patients' characteristics that enlarged the acupuncture effect (ie, acted as effect modifiers) were being female (P = 0.028), living in a multi-person household (P = 0.002), failure of other therapies before the study (P = 0.049), and former positive acupuncture experience (P = 0.005). DISCUSSION Future research to clarify the modifying effects with special focus on patients' expectations and other psychological variables is needed.