Reducing inappropriate lumbar MRI referrals: a Danish pre- and post-intervention study.

Abstract

Background: Low back pain (LBP) is the leading cause of disability worldwide. Despite guidelines advising against routine imaging, a significant proportion of patients are referred for lumbar spine magnetic resonance imaging (MRI) without an appropriate indication. This study aims to assess the impact of the intervention on the appropriateness of referrals and the proportion of referred patients from general practitioners (GPs) who underwent lumbar MRI.

Methods: A quasi-experimental design with pre- and post-intervention periods was employed. We included GP referrals for lumbar spine MRI at Silkeborg Regional Hospital, Denmark, among adults ≥ 18 years from 1 January 2019 to 31 August 2023. The intervention, which consisted of template-based correspondence letters and a guidance booklet, was implemented on 1 September 2022. Referrals were classified as either 'appropriate' or 'inappropriate' according to international guidelines. Interrupted time-series analysis with segmented regression was applied to evaluate change over time in referral appropriateness and the proportion of lumbar MRIs within 90 days of referral.

Results: A total of 5222 referrals were received (80.6% pre and 19.4% post intervention). Patient characteristics were comparable across the periods. The proportion of appropriate referrals increased from 49.7 to 60.0%. At the onset of the intervention, the level of appropriate referrals increased by 6.50% points (95% CI 0.71, 12.29), and the trend changed by 0.98 (95% CI 0.36, 1.59), reaching 0.90 (95% CI 0.30, 1.49). This implied a continued increase in the pre-post difference. The proportion of referred patients having lumbar MRIs decreased from 92.2 to 75.7%. At intervention onset, the level of lumbar MRIs changed by - 17.06 (95% CI - 23.25, - 10.88). However, post-intervention the trend changed, becoming positive (0.66, 95% CI - 0.05, 1.37), implying that the number of lumbar MRIs could return to pre-intervention level over time.

Conclusion: The intervention increased the proportion of appropriate referrals for lumbar MRI. For the proportion of MRIs performed, we found an immediate reduction, but this may not be sustained over time.