Psychological covariates of longitudinal changes in back-related disability in patients undergoing acupuncture
Bishop FL., Yardley L., Prescott P., Cooper C., Little P., Lewith GT.
Copyright © 2014 Wolters Kluwer Health, Inc. All rights reserved. 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.