Early versus late diagnostic MRI for low back pain among Washington State Workers: Evaluation of one-year health status

Background: Use of advanced diagnostic imaging has been increasing rapidly over the last decade. However, increased utilization may contribute to higher costs without concomitant improvements in health outcomes. Evidence-based guidelines for acute low back pain (LBP) maintain that that routine imaging is not necessary during the first month of symptoms for non-medically emergent patients, yet many LBP patients still receive early MRI. Within the workers' compensation population, LBP accounts for up to one third of workers' compensation medical costs.

Methods: The Washington Workers' Compensation Disability Risk Identification Cohort Study prospectively followed workers with LBP claims for one year. Baseline SF-36 and Roland Back Pain scores were ascertained at baseline and at one year, along with demographic, clinical, and cost information. Health status scores are compared among workers with MRIs to workers receiving late MRIs for LBP.

Results: Out of 1843 workers with LBP, 389 (21.1%) received an MRI for LBP; 208 (53.5%) had an early MRI. Bivariate analyses suggest that individuals with early MRI are more likely to be white, have a lower education, and be male. Initial analyses suggest that total time loss at one year (days drawing disability) does not significantly differ between early and late MRI cohorts. Multivariable analyses of outcomes at one year will control for age, sex, severity, comorbid conditions, and health status at baseline.

Conclusion: This study adds to the body of evidence to inform future policy decisions regarding the use of evidence-based guidelines for advanced imaging management within the workers' compensation system.