Primary care referral of patients with low back pain to physical therapy: impact on future health care utilization and costs.

STUDY DESIGN A retrospective cohort. OBJECTIVE To describe physical therapy utilization following primary care consultation for low back pain (LBP) and evaluate associations between the timing and content of physical therapy and subsequent health care utilization and costs. SUMMARY OF BACKGROUND DATA Primary care management of LBP is highly variable and the implications for subsequent costs are not well understood. The importance of referring patients from primary care to physical therapy has been debated, and information on how the timing and content of physical therapy impact subsequent costs and utilization is needed. METHODS Data were extracted from a national database of employer-sponsored health plans. A total of 32,070 patients with a new primary care LBP consultation were identified and categorized on the basis of the use of physical therapy within 90 days. Patients utilizing physical therapy were further categorized based on timing (early [within 14 d] or delayed)] and content (guideline adherent or nonadherent). LBP-related health care costs and utilization in the 18-months following primary care consultation were examined. RESULTS Physical therapy utilization was 7.0% with significant geographic variability. Early physical therapy timing was associated with decreased risk of advanced imaging (odds ratio [OR] = 0.34, 95% confidence interval [CI]: 0.29, 0.41), additional physician visits (OR = 0.26, 95% CI: 0.21, 0.32), surgery (OR = 0.45, 95% CI: 0.32, 0.64), injections (OR = 0.42, 95% CI: 0.32, 0.64), and opioid medications (OR = 0.78, 95% CI: 0.66, 0.93) compared with delayed physical therapy. Total medical costs for LBP were $2736.23 lower (95% CI: 1810.67, 3661.78) for patients receiving early physical therapy. Physical therapy content showed weaker associations with subsequent care. CONCLUSION Early physical therapy following a new primary care consultation was associated with reduced risk of subsequent health care compared with delayed physical therapy. Further research is needed to clarify exactly which patients with LBP should be referred to physical therapy; however, if referral is to be made, delaying the initiation of physical therapy may increase risk for additional health care consumption and costs.