Predictors of physical therapy clinic performance in the treatment of patients with low back pain syndromes.

Abstract

Little is known about organizational and service delivery factors related to quality of care in physical therapy. This study sought to identify characteristics related to differences in practice outcomes and service utilization. The sample comprised 114 outpatient clinics and 1,058 therapists who treated 16,281 patients with low back pain syndromes during the period 2000-2001. Clinics participated with the Focus on Therapeutic Outcomes, Inc (FOTO) database. Hierarchical linear models were used to risk adjust treatment outcomes and number of visits per treatment episode. Aggregated residual scores from these models were used to classify each clinic into 1 of 3 categories in each of 3 types of performance groups: (1) effectiveness, (2) utilization, and (3) overall performance (ie, composite measure of effectiveness and utilization). Relationships between clinic classification and the following independent variables were examined by multinomial logistic regression: years of therapist experience, number of physical therapists, ratio of physical therapists to physical therapist assistants, proportion of patients with low back pain syndromes, number of new patients per physical therapist per month, utilization of physical therapist assistants, and setting. Clinics that were lower utilizers of physical therapist assistants were 6.6 times more likely to be classified into the high effectiveness group compared with the low effectiveness group, 6.7 times more likely to be classified in the low utilization group compared with the high utilization group, and 12.4 times more likely to be classified in the best performance group compared with the worst performance group. Serving a higher proportion of patients with low back pain syndromes was associated with an increased likelihood of being classified in the lowest or middle group. Years of physical therapist experience was inversely associated with being classified in the middle utilization group compared with the highest utilization group. These findings suggest that, in the treatment of patients with low back pain syndromes, clinics that are low utilizers of physical therapist assistants are more likely to provide superior care (ie, better patient outcomes and lower service use).