Impact of Out-of-Pocket Expenditure on Physical Therapy Utilization for Nonspecific Low Back Pain: Secondary Analysis of the Medical Expenditure Panel Survey Data.

BACKGROUND Physical therapy decreases low back pain, improves function, and may lead to decreased use of medical services. However, factors predicting physical therapy utilization for patients with low back pain are not well understood. OBJECTIVES The purpose of this study was to identify the impact of out-of-pocket expenditure on physical therapy utilization for US adults with nonspecific low back pain. DESIGN This study was a secondary analysis of retrospective Medical Expenditure Panel Survey data. METHODS The participants were US adults with nonspecific low back pain. The outcome variable was the number of visits per episode of care. The research variable was out-of-pocket expenditure. Covariate variables were Medical Outcomes Study 12-Item Short-Form Health Survey (SF-12) component scores. Descriptive statistics and multiple linear regression analyses were performed. RESULTS Three hundred fourteen adults met the inclusion criteria and submitted SF-12 scores, representing nearly 4 million adults. Out-of-pocket expenditure, physical component score, and the age-insurance category "18-64 years with public coverage only for all of the year or uninsured all of the year" negatively predicted visits per episode of care in the final regression model. LIMITATIONS Limitations of the study included use of a nonexperimental design, lack of information about symptom severity and content of physical therapy, and SF-12 scores were not taken coincidental with the episode of care. CONCLUSIONS Out-of-pocket expenditure negatively predicts physical therapy utilization. More research is needed to identify all factors influencing physical therapy utilization so that effective health policies may be developed.