Satisfaction as a predictor of clinical outcomes among chiropractic and medical patients enrolled in the UCLA Low Back Pain Study

Study Design. Observational study conducted within a randomized clinical trial. Objectives. The objective of this study is to estimate the effects of patient satisfaction on subsequent changes in pain and disability among low back pain patients randomized to chiropractic or medical care in a managed-care practice setting. Summary of Background Data. Recent studies of low back pain treatments have shown chiropractic patients to be more satisfied with their care than medical patients. However, little is known about the relation between patient satisfaction and clinical outcomes. Methods. A total of 681 low back pain patients presenting to three southern California healthcare clinics and screened for serious spinal pathology and contraindications were randomized to medical care with and without physical therapy, and chiropractic care with and without physical modalities, and followed for 18 months. Satisfaction with back care was measured on a 40-point scale and observed at 4 weeks following randomization. The primary outcome variables, observed between 6 weeks and 18 months of follow-up, are average and most severe low back pain intensity in the past week, assessed with 0 to 10 numerical rating scales, low back-related disability, assessed with the 24-item Roland-Morris Disability Questionnaire, and remission from clinically meaningful pain and disability. Perceived change in low back symptoms was a secondary outcome. Results. Greater satisfaction increased the odds of remission from clinically meaningful pain and disability at 6 weeks (adjusted odds ratio [OR] for 10-point increase in satisfaction=1.61, 95% confidence interval [CI]=0.99, 2.68), but not at 6, 12, or 18 months ( 6 months: adjusted OR=1.05, 95% CI=0.73, 1.52; 12 months: adjusted OR=0.94, 95% CI=0.67, 1.32; 18 months: adjusted OR=1.07; 95% CI=0.76, 1.50). Perception of improvement was greater among highly satisfied than less satisfied patients throughout the 18-month follow-up period. The estimated effects of satisfaction on clinical outcomes were similar for medical and chiropractic patients. Conclusions. Patient satisfaction may confer small short-term clinical benefits for low back pain patients. Long-term perceived improvement may reflect, in part, perceived past improvement as measured by satisfaction.