Determinants of return-to-work among low back pain patients.

This prospective study identifies physical, behavioral, and psychosocial correlates of subsequent employment status in a sample of low back pain patients. The sample of 150 subjects was drawn from 2 populations of persons with chronic low back pain: 87 individuals who were receiving care at a university low back pain clinic, and 63 individuals who had applied for (but not yet received) Social Security compensation on the basis of low back pain. All subjects had worked at least 3 months prior to their latest unemployment period and were currently out of work. Initial assessment included a medical history, physical examination, biomechanical testing, psychiatric interview, and MMPI testing. All subjects were followed up 6 months later to determine whether they had returned to work. Cross-sectional group comparisons at the time of initial assessment showed that, after controlling for the effects of age, the two samples differed on several physical and biomechanical measures, the Social Security group reflecting a more chronic picture. Group differences on physical variables were found, but most significant differences disappeared when adjusted for length of time out-of-work. Longitudinal analyses showed that few objective physical or biomechanical measures were associated with return-to-work at 6 months, while a number of psychosocial variables were significant predictors of 6-month work status. The data suggest that exclusive reliance on the physical examination to determine level of disability, without consideration of psychosocial conditions, and without adjusting for the confounding effects of age and length of time out-of-work, is not empirically justified. Logistic regression analysis was used to ascertain the relative contribution of each predictor to outcome and to illustrate the hypothetical effects of changes in the levels of selected risk factors on the likelihood of return-to-work. Implications for interventions with low back pain patients are discussed and future research directions suggested.