Intravitreal anti-vascular endothelial growth factor therapy for retinal diseases in Norway from 2011 to 2021: A combined registry and survey study

Purpose: To investigate the use of intravitreal anti-vascular endothelial growth factor (anti-VEGF) therapy in Norway from 2011 to 2021 and explore how the eye departments organized their injection services. 

Methods: We combined data from the Norwegian Patient Registry (NPR) with survey responses from Norway's 22 eye departments. The NPR data encompassed all registered intravitreal injection episodes from 2011 to 2021. The survey contained questions about local treatment practices and emphasized neovascular age-related macular degeneration (nAMD), retinal vein occlusion and diabetic macular edema. 

Results: A total of 47247 unique patients received 841 646 intravitreal injections in the study period. The number of patients per year increased from 6522 in 2011 to 20 635 in 2021. The number of injections per year increased from 30 926 in 2011 to 125 258 in 2021. The most frequent diagnosis was nAMD. In 2021, the age-adjusted treatment activity in Norway's 11 counties ranged from 47.8 to 75.5 injections per 1000 inhabitants aged ≥50 years. The use of aflibercept gradually exceeded bevacizumab, but the aflibercept proportion per county ranged from 38 to 82% in 2021. The survey revealed varying treatment practices, local guidelines were often absent, and only half of the departments defined a lower visual limit for initiating or maintaining treatment. 

Conclusion: The use of intravitreal anti-VEGF therapy increased considerably from 2011 to 2021, but there was considerable regional variation in treatment activity, drug utilization and organization of injection services. These findings emphasize the need for strengthened governance and national guidelines to ensure equal treatment nationally.