Study design: Retrospective cohort study.
Objective: To determine the effect of early (receipt ≤30 d postonset) magnetic resonance imaging (MRI) on disability and medical cost outcomes in patients with acute, disabling, work-related low back pain (LBP) with and without radiculopathy.
Summary of background data: Evidence-based guidelines suggest that, except for "red flags," MRI is indicated to evaluate patients with persistent radicular pain, after 1 month of conservative management, who are candidates for surgery or epidural steroid injections. Prior research has suggested an independent iatrogenic effect of nonindicated early MRI, but it had limited clinical information and/or patient populations.
Methods: A nationally representative sample of workers with acute, disabling, occupational LBP was randomly selected, oversampling those with radiculopathy diagnoses (N = 1000). Clinical information from medical reports was used to exclude cases for which early MRI might have been indicated, or MRI occurred more than 30 days postonset (final cohort = 555). Clinical information was also used to categorize cases into "nonspecific LBP" and "radiculopathy" groups and further divided into "early-MRI" and "no-MRI" subgroups. The Cox proportional hazards model examined the association of early MRI with duration of the first episode of disability. Multivariate linear regression models examined the association with medical costs. All models adjusted for demographic and medical severity measures.
Results: In our sample, 37% of the nonspecific LBP and 79.9% of the radiculopathy cases received early MRI. The early-MRI groups had similar outcomes regardless of radiculopathy status: much lower rates of going off disability and, on average, $12,948 to $13,816 higher medical costs than the no-MRI groups. Even in a subgroup with relatively minimal disability impact (≤30 d of total lost time post-MRI), medical costs were, on average, $7643 to $8584 higher in the early-MRI groups.
Conclusion: Early MRI without indication has a strong iatrogenic effect in acute LBP, regardless of radiculopathy status. Providers and patients should be made aware that when early MRI is not indicated, it provides no benefits, and worse outcomes are likely.
Level of evidence: 3.