Abstract
Purpose :
Diabetic retinopathy (DR) is a leading cause of blindness worldwide and Indigenous Australians suffer disproportionately from diabetic-related blindness. Exploring ethnic variation in disease is useful for service planning and can lead to identification of ethnic-specific modifiable risk factors. Existing studies on DR prevalence in Indigenous diabetic patients have reported variable results. We performed a systematic review to summarise the evidence-base relating to DR prevalence amongst Indigenous and non-Indigenous Australians.
Methods :
This study was conducted following Joanna Briggs Institute (JBI) guidance on systematic reviews of prevalence studies (PROSPERO ID:CRD42022259048). We performed database searches of Medline (Ovid), EMBASE, and Web of Science up to October 2021 using a search strategy designed by an information specialist. We included studies reporting DR prevalence amongst diabetic patients (type 2 or mixed) in Indigenous and non-Indigenous Australian populations, with last data collected after January 2000. Two independent reviewers performed risk of bias assessments using a 9-item appraisal tool developed by the JBI. Meta-analysis was performed using double arcsine transformation and a random-effects model comparing Indigenous and non-Indigenous subgroups.
Results :
Of 801 records identified through database searches, 14 studies met inclusion criteria and were included in the quantitative synthesis. The Indigenous subgroup scored significantly lower on the appraisal tool compared to the non-Indigenous subgroup (mean score 51% vs 78%, p=0.04). Pooled DR prevalence in the Indigenous subgroup was 29% [95% CI:22-37%] compared to 25% [95% CI:17-33%] in the non-Indigenous subgroup, although there was significant heterogeneity in the pooled results (p<0.01, I2>94%). Of 3 studies reporting within-study comparisons, all 3 found higher DR prevalence amongst Indigenous patients.
Conclusions :
Indigenous studies scored lower for methodological quality compared to non-Indigenous studies. Pooled subgroup differences in DR prevalence were inconclusive due to the presence of significant heterogeneity. Further analysis into sources of heterogeneity is needed. Within-study comparisons suggest that DR may be more common amongst Indigenous Australians. Analysis of modifiable risk factors contributing to ethnic variation requires further exploration.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.