Differences in retinopathy prevalence and progression between Anglo-Celt and Aboriginal Australians: the Fremantle Diabetes Study Phase II

Background: Indigenous populations have higher rates of diabetes and diabetic complications, yet there is a paucity of contemporary data on diabetic retinopathy (DR) prevalence and incidence in urban dwelling Aboriginal Australians. Aims: The aim of the study was to compare the prevalence of DR and incidence of new or worsening DR between Aboriginal Australians and Anglo-Celts with Type 2 diabetes. Methods: Participants from the community-based Fremantle Diabetes Study Phase II (817 Anglo-Celts, 94 Aboriginal people) recruited between 2008 and 2011 underwent fundus photography at baseline and biennial reviews. The prevalence of any DR and moderate non-proliferative DR (NPDR), and the incidence of new or worsening DR were ascertained using baseline and 4-year follow-up data. Results: Compared with Anglo-Celts, the Aboriginal participants had a higher prevalence of any DR (33.0% vs 52.1%) and moderate NPDR or worse (5.1% vs 24.4%), and new or worsening DR during follow up (6.7% vs 23.5%). The unadjusted odds ratios (95% confidence interval) of any DR and moderate NPDR at baseline were 2.21 (1.43, 3.39) and 5.98 (3.40, 10.50), respectively, and of new or worsening DR 4.32 (1.33, 13.98). In adjusted models, Aboriginal ethnicity was only associated with the prevalence of moderate NPDR or worse (5.58 (2.44, 12.76)). Conclusions: Aboriginal participants had a higher prevalence of DR and new or worsening DR, reflecting conventional risk factors including suboptimal glycaemic control. Their significantly higher odds of moderate NPDR or worse in adjusted models suggest ethnic-specific determinants of DR severity. These findings highlight the need for equitable, culturally appropriate diabetes/ophthalmic care.