Intravitreal therapy for retinal diseases in Norway 2011-2015

During the past decade, intravitreally administered biologic drugs have advanced the treatment of retinal diseases, such as wet age-related macular degeneration (AMD), diabetic macular oedema and retinal venous occlusions. The drugs as well as the necessary disease management imply considerable economic burden on healthcare systems. This Norwegian study documents the rates of use of intravitreal therapies and intercounty variation over a 5-year period.

We collected data from the Norwegian Patient Register for all episodes of care encompassing intravitreal therapy during the period 2011-2015. For each episode, we received information on patient age, sex, county of residence, diagnosis and name of drug injected.

During the study period, 21 277 patients had in total 236 857 episodes of care. The number of intravitreal injections doubled from 2011 to 2015, reaching 63 601 injections in 2015, of which 77% were for diagnosed wet AMD. In 2015, the age-adjusted number of episodes varied from 19 to 55 per 1000 population aged 50+ across Norway's 19 counties. The age-adjusted number of patients treated per 1000 population aged 50+ varied from 5.22 to 8.35.

The use of intravitreal injections increased rapidly with wet AMD as the most frequent diagnosis and with varying utilization across Norway's 19 counties. The causes of the varying use of intravitreal therapies could not be established but may reflect variation in disease prevalence, treatment capacity, travel distance to the nearest ophthalmic service and lack of national treatment guidelines. The geographic variation in utilization may challenge policy goals of equitable care and warrants further studies.