Factors associated with early magnetic resonance imaging utilization for acute occupational low back pain: a population-based study from Washington State workers' compensation.

STUDY

DESIGN

A population-based, prospective cohort study.

OBJECTIVE

To identify demographic, job-related, psychosocial, and clinical factors associated with the use of magnetic resonance imaging (MRI) within 6 weeks from injury (early MRI) among workers' compensation claimants with acute occupational low back pain (LBP).

SUMMARY OF BACKGROUND DATA: Early MRI may be associated with increased use of services for treatment and costs. To understand utilization and most appropriately apply guidelines, it is important to identify factors associated with early imaging use for occupational LBP.

METHODS

Workers (N = 1830) were interviewed 3 weeks (median) after submitting a workers' compensation claim for a back injury. Demographic, work, health, clinical, and injury characteristics were ascertained from interviews, medical records, and administrative data. Modified Poisson regression analyses identified factors associated with early MRI use.

RESULTS

Among respondents, 362 (19.8%) received an early MRI. Multivariable regression showed that male workers were 43% more likely to receive an early MRI than female workers (incident rate ratio [IRR]: 1.43, 95% confidence interval [CI]: 1.12-1.82). Initial visit type with a surgeon was associated with 78% greater likelihood of receiving an early MRI than that with a primary care physician (IRR: 1.78, 95% CI: 1.08-2.92). Having a chiropractor as the initial provider was associated with a reduced likelihood of early MRI (IRR: 0.53, 95% CI: 0.42-0.66). Workers with elevated work fear-avoidance, higher Roland scores, or increased injury severity were more likely to receive early MRI than counterparts with lower levels or scores.

CONCLUSION

Nearly 20% of the injured workers with LBP receive early MRI, a rate similar to that reported elsewhere. Early MRI may lead to greater subsequent interventions, potentially poorer outcomes, and increased health care expenditures. On the basis of the characteristics of patients with uncomplicated occupational LBP, providers may be able to provide tailored care, and providers and policy makers may better understand the utilization of imaging and adherence to clinical guidelines.