Prediction of costs-of-illness in patients with low back pain undergoing orthopedic outpatient rehabilitation.

The objectives of this study were (1) to assess societal costs-of-illness and their changes in the year prior to and after outpatient rehabilitation (OPR) in initially gainfully employed persons with low back pain and (2) to identify predictors (cost drivers) for high overall costs in the year after the intervention. The health economical analysis is part of a prospective clinical trial investigating patients participating in orthopedic OPR. In all gainfully employed patients (n=244) resource consumption and productivity losses were assessed prior to OPR and 12 months afterwards. Overall annual medical costs per person were estimated. Parameters associated with high overall costs in the 12 months after OPR were predicted by multivariate logistic regression analysis. All sociodemographic, motivational, clinical, psychological, therapeutic and vocational variables were included as possible predictors. Costs due to sick leave periods represent the major component (83%/58%) of overall costs in both periods. The comparison of costs 12 months before and after OPR reveals a significant reduction from 8050 to 3200 per person, primarily caused by decreasing sick leave costs and the reduction of costs related to inpatient treatment. The prediction analysis reveals that patients with limited functional abilities, with problems due to strenuous labour, with low expectations in terms of possible improvement after OPR, with a high pain score or with limited satisfaction with working colleagues have a significantly higher risk for costs exceeding 2200 after OPR. The identified cost drivers can be used to develop multimodal therapeutic measures, which should be employed during the OPR intervention in order to prevent future costs.