Carla Sabariego, Mirjam Brach, Gerold Stucki
DOI: 10.2340/16501977-0845

Objective: To identify determinants of direct medical costs among patients with osteoporosis, osteoarthritis, back pain or fibromyalgia.
Design: Cross-sectional study.
Participants: Convenience sample of 410 patients undergoing outpatient rehabilitation.
Methods: Resource use was assessed with a self-report retro­spective questionnaire, and direct medical costs were calculated considering outpatient physician services, non-physician health services, medication and inpatient treatment. Non-parametric bootstrap techniques with 1,000 replications were used to estimate means of costs and their 95% confidence intervals (CI). To identify determinants of costs, a generalized linear model with log link function and gamma distribution, as well as a multivariate logistic regression analysis, were performed.
Results: Medical indication (p < 0. 001), age (p = 0. 034) and the scales of the Short Form-36 (SF-36) role physical (p < 0. 001), physical functioning (p = 0. 036), social functioning (p = 0. 047) and vitality (p = 0. 005) were significant predictors of direct medical costs, whereas the medical indication fibromyalgia (odds ratio (OR) = 5. 74, 95% CI 2. 051–16. 066, p = 0. 001), the Short-Form 36 (SF-36) scale role physical (OR = 0. 988, 95% CI 0. 980–0. 996, p = 0. 002) and comorbidity (OR = 1. 161, 95% CI 1. 043–1. 292, p = 0. 006) were statistically significant determinants of high direct medical costs beyond the median.
Conclusion: Our work confirms known predictors of direct medical costs and broadens the understanding of determinants of direct medical costs beyond the median.