Physician Self-Referral of Physical Therapy Services for Patients with Low Back Pain: Implications for Use, Types of Treatments Received and Expenditures.

Abstract

Prior research on treatment of low back pain has documented large increases in use of spinal surgery, MRIs and lumbosacral injections linked to physician self-referral arrangements. No recent research has examined whether physician ownership of physical therapy services results in greater use of physical therapy to treat low back pain. The objective of this study is to investigate whether physician ownership of physical therapy services affects frequency of use, visits and types of physical therapy services received by patients with low back pain. Using claims records from insured patients covered by Blue Cross Blue Shield of Texas (2008-2011) we compared several metrics of use of physical therapy services for low back pain episodes controlling for self-referral status. We identified 158,151 low back pain episodes, 27% met the criteria to be classified as "self-referral." Only 10% of "non-self-referral" episodes received physical therapy compared to 26% of self-referral episodes (p<0.001). The unadjusted and regression adjusted self-referral effect was identical - about 16 percentage point difference (p<0.001). Among patients who received some physical therapy, self-referral episodes were comprised of 2.26 fewer visits and 11 fewer physical therapy service units (p<0.001). Non-self-referring episodes included a significantly higher proportion of "active" (hands on or patient engaged) as opposed to "passive" treatments (p<0.001). The regression-adjusted difference was 30 percentage points when measured as actual counts and 29 percentage points when measured in RVUs (p<0.001). Total spending on back-related care was 35% higher for self-referred episodes compared to their non-self-referred counterparts (p<0.001). Ownership of physical therapy services influence physicians' referral to initiate a course of physical therapy to treat low back pain, but also affect the types of physical therapy services a patient receives.