Variation among Primary Care Physicians in the Use of Imaging for Older Patients with Acute Low Back Pain

BACKGROUND: Diagnostic imaging is not recommended in the evaluation and management of non-specific acute low back pain. OBJECTIVE: To estimate the variation among primary care providers (PCPs) in the use of diagnostic imaging for older patients with non-specific acute low back pain. DESIGN AND PARTICIPANTS: Retrospective cohort study using 100 % Texas Medicare claims data. We identified 145,320 patients aged 66 years and older with nonspecific acute low back pain during the period January 1, 2007, through November 30, 2011, cared for by 3297 PCPs. MAIN MEASURES: We tracked whether each patient received lumbar imaging (radiography, computed tomography [CT], or magnetic resonance imaging [MRI]) within 4 weeks of the initial visit. Multilevel logistic regression models were used to estimate physician-level variation in imaging use. KEY RESULTS: Among patients, 27.2 % received radiography and 11.1 % received CT or MRI within 4 weeks of the initial visit for low back pain. PCPs varied substantially in the use of imaging. The average rate of radiography within 4 weeks was 53.9 % for PCPs in the highest decile, compared to 6.1 % for PCPs in the lowest decile. The average rates of CT/MRI within 4 weeks were 18.5 % vs. 3.2 % for PCPs in the highest and lowest deciles, respectively. The specific physician seen by a patient accounted for 25 % of the variability in whether imaging was performed, while only 0.44 % of the variance was due to measured patient characteristics and 1.4 % to known physician characteristics. Use of imaging by individual physicians was stable over time. CONCLUSIONS: PCPs vary substantially in the use of imaging for non-specific acute low back pain. Provider-level measures can be employed to provide feedback to physicians in an effort to modify imaging use.