Screening for diabetic retinopathy in James Bay, Ontario: a cost-effectiveness analysis

Abstract

Background: Retinopathy is a common complication of diabetes mellitus that if detected early by regular retinal examinations can be treated; thus, blindness can be delayed or prevented. Providing high-quality retinal screening is difficult, especially in rural and remote areas. Canada's First Nations population has a higher prevalence of diabetes and is, in general, more geographically isolated than the broader Canadian population. We modelled the cost-effectiveness of retinopathy screening by travelling retina specialists versus retinal photography with a portable digital camera in an isolated First Nations cohort with diabetes.

Methods: The 2 screening programs were modelled to run concurrently for 5 years, with outcomes evaluated over 10 years. To construct economic models for the population of Cree individuals living in the western James Bay area of northern Ontario, we used available data on the prevalence of diabetes in the area and estimates of the incidence of retinopathy derived from the published literature. We compared the screening models and calculated total costs, visual outcome, costs per sight-year saved and costs per quality-adjusted life year (QALY). We also estimated the costs of implementing a screening program for all First Nations individuals in Ontario with diabetes and no access to an ophthalmologist.

Results: From the perspective of the health care system the camera program was preferable to the specialist-based program. Over 10 years, 67 v. 56 sight years were saved, compared with no screening, at costs of 3900 Canadian dollars v. 9800 Canadian dollars per sight year and 15,000 Canadian dollars v. 37,000 Canadian dollars per QALY. Generalizing these results to the province of Ontario, the camera system could allow most isolated First Nations people with diabetes to be screened for 5 years for approximately 1.2 million Canadian dollars.

Interpretation: A portable retinal camera is a cost-effective means of screening for diabetic retinopathy in isolated communities of at-risk individuals.

Fig. 1: Typical image of nonproliferative diabetic retinopathy with clinically significant macular edema (CSME).

Fig. 2: Representative flow chart for evaluating visual outcomes of screening for diabetic retinopathy in programs based on visits by retina specialists (S) or the use of a portable retinal camera (C). Superscript 1 indicates data from the diabetic retinopathy screening program in western James Bay, in northern Ontario, for 145 consecutive Cree individuals with diabetes, of whom 25.5% had background diabetic retinopathy (BDR), 1.4% high-risk characteristics (HRC) for severe vision loss (equivalent to proliferative diabetic retinopathy with certain clinical criteria) and 6.9% CSME; these data are the best cross-sectional information available for the Cree population in 1997–1998. Superscript 2 indicates data from observational studies comparing modes of ophthalmic assessment for diabetic retinopathy.,,,,,,,,,, Superscript 3 indicates data from multicentre prospective randomized clinical trials on the effect of laser treatment on vision loss. Severe vision loss = 20/800.,

Fig. 3: Cost per quality-adjusted life year (QALY) when various proportions of individuals with diabetes were screened in the 2 programs.

Fig. 4: Cost per year of vision saved when various proportions of individuals with diabetes were screened in the 2 programs.