Diabetic retinopathy screening in a high-latitude rural population of Northern Norway.

BACKGROUND: To estimate the prevalence of diabetic retinopathy (DR) and diabetic macular edema (DME) in Finnmark, the northernmost county in Norway, and to assess the safety and quality of a two-step screening routine utilizing certified nurse or optometrist as primary graders. METHODS: This cross-sectional study included 300 patients attending for routine DR screening at Kirkenes Hospital between October 2021 and December 2022. Retinal images were graded independently by a certified nurse/optometrist and an ophthalmologist. Discrepancies were resolved by a retina specialist and intergrader agreement was assessed. RESULTS: The prevalence of any DR was 56.3% (82.8% in type I diabetes (T1D), 53.5% in type II (T2D)). DME based on photography was present in 11.3%, and in 12.3% based on OCT. Severe non-proliferative DR (NPDR) or proliferative DR (PDR) was observed in 37.9% of participants with T1D and 12.2% of those with T2D. Intergrader agreement for DR grade and DME based on photography was high; Cohen’s weighted kappa (k) was 0.96 and 0.91 respectively. Intergrader agreement for identifying referable DR was 0.97. CONCLUSIONS: The prevalence of DR and DME in this rural northern Norwegian hospital-based cohort was higher than previously reported Norwegian estimates, likely partly due to differences in population characteristics and screening methodology. The two-step screening model demonstrated high accuracy in differentiating referable from non-referable DR, supporting its implementation to improve screening efficiency while maintaining diagnostic safety.