Objectives
Diabetic retinopathy (DR) remains a leading cause of blindness despite annual screening recommendations and the availability of effective treatments. The impact on blindness of efforts to improve screening compliance is often evaluated using economic models due to the long-term nature of DR progression. Understanding the relationship between compliance and blindness prevention in previous modeling studies can aid decision makers evaluating new DR screening programs in their jurisdictions.
Methods
A review of published economic models evaluating annual DR screening programs was conducted. Data extraction captured the country and year of analysis, target population, time horizon, screening technology, compliance levels, and blindness outcomes. Studies not reporting compliance or blindness outcomes were excluded. Data from the remaining studies were analyzed for the relationship between improvements in compliance and reductions in blindness.
Results
Of the twenty-one economic models for DR screening reviewed, twelve reported annual screening compliance and blindness outcomes, while only seven reported outcomes in sufficient detail for subsequent analysis. Compliance and blindness outcomes varied widely by population, horizon, and screening technology. Studies reporting cases of blindness estimated that 50–100% improvements in compliance were associated with 29–90% reductions in cases of blindness. Studies reporting years of blindness estimated that 55–100% improvements in compliance were associated with 35–60% reductions in years of blindness. On average, a 10 percentage-point increase in compliance was associated with a 6.2% reduction in cases of blindness and a 5.9% reduction in years of blindness.
Conclusions
Economic models for DR screening often fail to report the study details and outcomes required for decision makers to interpret the study findings. Across the variety of populations and technologies considered in published economic models, the available data suggest that each 10 percentage-point increase in DR screening compliance is associated with an approximate 6% reduction in blindness.
