Implementation of diabetic retinopathy screening in the Oslo region, Norway: a 3-year pilot study

Purpose: Determine the prevalence and progression of diabetic retinopathy (DR) and its risk factors over a three year period in a pilot DR screening program in the Oslo region. Methods: The pilot screening program enrolled 90 adult patients with type 1 (T1D) or type 2 diabetes (T2D) from December 2019 to January 2021. Patients were referred by general practitioners and underwent annual DR screening, including fundus photography and optical coherence tomography (OCT) imaging. Baseline and follow-up data included socio-demographic parameters, diabetes history and medication, glycated haemoglobin (HbA1c), visual acuity, blood pressure, and intraocular pressure. DR severity was graded using the International Clinical Disease Severity Scale for DR, and diabetic macular edema (DME) was identified based on OCT findings. Cox regression analyses were conducted to identify factors associated with DR progression. Results: At baseline, prevalence of DR was 27.8%, with 6.7% of the patients exhibiting vision-threatening DR (VTDR). Over the 3-year follow-up, 24.7% of the patients either developed or showed a progression of DR, with 4% developing VTDR. Duration of diabetes and urine albumin-to-creatinine ratio were significantly associated with DR progression (hazard ratio 1.07 (95% confidence interval 1.02-1.12) and 1.03 (95% confidence interval 1.01-1.06), respectively). 13.3% of patients were lost to follow-up, primarily due to the COVID-19 pandemic. Conclusion: Most patients had stable DR over the 3 years period. Diabetes duration and albuminuria predicted progression, supporting extended screening intervals for low-risk patients with risk-based stratification.