The prevalence of diabetic retinopathy in Indigenous and non-Indigenous populations in Canada: systematic review and meta-analysis.

Objective: To estimate the prevalence of diabetic retinopathy (DR) in Canada and to explore possible differences between Indigenous and non-Indigenous Canadians with diabetes.

Design: Systematic review and meta-analysis.

Methods: The Ovid MEDLINE, EMBASE, and Web of Science Databases were searched. The prevalence of (i) DR, (ii) diabetic macular edema (DME), (iii) proliferative diabetic retinopathy (PDR), (iv) vision-threatening diabetic retinopathy (VTDR), and (v) PDR complications was estimated. Meta-analyses were performed using Freeman Tukey double arcsine transformations and random-effects modelling. Grading of Recommendations, Assessment, Development and Evaluations (GRADE) guidelines informed the certainty of evidence.

Results: Sixteen studies (17,989 individuals) were included. In the Indigenous and non-Indigenous groups respectively, the pooled prevalence of DR is estimated to be 30.5% (95% CI: 16.7%, 46.4%; GRADE: low), and 32.8% (95% CI: 20.7%, 46.3%; GRADE: low), respectively. The prevalence of PDR is estimated to be 2.8% (95% CI: 0.9%, 5.7%; GRADE: moderate), and 1.9% (95% CI: 0.7%, 3.7%; GRADE: moderate), respectively. The prevalence of DME is estimated to be 3.8% (95% CI: 0.0%, 16.0%; GRADE: moderate) and 4.5% (95% CI: 2.5%, 7.0%; GRADE: moderate), respectively; and the prevalence of VTDR is estimated to be 13.6% (95% CI: 5.2%, 25.1%; GRADE: low) and 5.8% (95% CI: 2.5%, 10.4%; GRADE: low), respectively. High-quality evidence is lacking.

Conclusions: There may be no difference in the prevalence of DR between Indigenous and non-Indigenous Canadians; however, Indigenous Canadians likely have a higher prevalence of VTDR. The uniformly high prevalence across both populations underscores the importance of delivering culturally appropriate diabetes care targeted at reducing risk factors and increasing DR screening in the Canadian community.