Psychological Covariates of Longitudinal Changes in Back-related Disability in Patients Undergoing Acupuncture

OBJECTIVES To identify psychological covariates of longitudinal changes in back-related disability in patients undergoing acupuncture. MATERIALS AND METHODS A longitudinal postal questionnaire study was conducted with data collection at baseline (pretreatment), 2 weeks, 3, and 6 months later. A total of 485 patients were recruited from 83 acupuncturists before commencing acupuncture for back pain. Questionnaires measured variables from 4 theories (fear-avoidance model, common-sense model, expectancy theory, social-cognitive theory), clinical and sociodemographic characteristics, and disability. Longitudinal multilevel models were constructed with disability over time as the outcome. RESULTS Within individuals, reductions in disability (compared with the person's individual mean) were associated with reductions in: fear-avoidance beliefs about physical activity (β=0.11, P<0.01) and work (β=0.03, P<0.05), catastrophizing (β=0.28, P<0.05), consequences (β=0.28, P<0.01), concerns (β=0.17, P<0.05), emotions (β=0.16, P<0.05), and pain identity (β=0.43, P<0.01). Within-person reductions in disability were associated with increases in: personal control (β=-0.17, P<0.01), comprehension (β=-0.11, P<0.05) and self-efficacy for coping (β=-0.04, P<0.01). Between individuals, people who were less disabled had weaker fear-avoidance beliefs about physical activity (β=0.12, P<0.01), had more self-efficacy for coping (β=-0.07, P<0.01), perceived less severe consequences of back pain (β=0.87, P<0.01), had more positive outcome expectancies (β=-0.30, P<0.05), and appraised acupuncture appointments as less convenient (β=0.92, P<0.05). DISCUSSION Illness perceptions and, to a lesser extent, self-efficacy and expectancies can usefully supplement variables from the fear-avoidance model in theorizing pain-related disability. Positive changes in patients' beliefs about back pain might underpin the large nonspecific effects of acupuncture seen in trials and could be targeted clinically.