Incidence of diabetic retinopathy in indigenous Australians within Central Australia: the Central Australian Ocular Health Study

Abstract

BACKGROUND: To estimate the incidence of diabetic retinopathy (DR) within the indigenous Australian population living in Central Australia. DEISGN: Clinic-based cohort study. PARTICIPANTS: One thousand eight hundred eighty-four individuals aged ≥20 years living in one of 30 remote communities within the statistical local area of ‘Central Australia’. METHODS: Among those with diabetes mellitus (DM) (n = 1040), 432 (42%) were reviewed between 6 months and 3 years (median 21 months) after the initial examination. DR in participants with DM was graded using the Early Treatment of Diabetic Retinopathy Study classification. Baseline results were compared with those at follow-up. MAIN OUTCOME MEASURES: The incidence of any DR and vision-threatening DR (clinically significant macular oedema and/or proliferative DR) in at least one eye. RESULTS: Of those with DM but without DR at baseline, 8.41% (9.42% of those aged 40 years or older) per year developed DR. Meanwhile, 0.7% (0.92% for those aged ≥40 years) of those with no DR at baseline developed vision-threatening DR per year, increasing to 8.4% per year for those with minimal or mild non-proliferative DR, and 28.2% per year for those with moderate or severe non-proliferative DR at baseline. CONCLUSION: Our study has estimated the annual incidence rates of DR among indigenous Australians living within Central Australia. These rates are similar to those from the non-indigenous population, and highlight the need for good surveillance and service provision in a population where the prevalence of diabetes is very high and the logistics of screening are complex.