Variations in general practitioners' referrals to low-value MRI examinations in Norway: A nationwide register-based...

Large variations in diagnostic imaging use raise concerns about low-value care, inequity, and inefficient use of resources. Magnetic resonance imaging (MRI) of the head, lumbosacral spine, and knee has been identified as potentially low-value examinations in several clinical contexts.

To examine variation in general practitioners' referrals to low-value MRI examinations in Norway and assess whether differences are associated with GP and practice characteristics.

Using national registry data, we linked patients' completed MRI examinations to their regular GP and calculated GP-specific MRI rates per 1000 listed patients. We classified GPs into deciles and compared the characteristics of GPs in the highest (High-10) and lowest (Low-10) referral deciles. We examined predictors of variation using pooled OLS regression models with year fixed effects and GP-clustered standard errors.

GPs in the top referring decile (High-10) referred patients for potentially low-value MRI examinations at three times the rate of those in the lowest referring decile (Low-10). Experienced (specialist-certified) GPs referred approximately 2.7 fewer examinations per 1000 listed patients per year than less experienced GPs (non-specialists). Shorter consultation times, higher consultation frequency and higher hourly fee income were all associated with higher MRI use - with the strongest association for private MRI. A higher patient disease burden was associated with more total examination, but fewer private examinations per 1000 listed patients per year.

Referral rates varied markedly between GPs. Specialist-certified GPs had lower rates than non-specialists, and higher activity levels and income from fees were associated with higher referral rates - particularly to private providers.