Is ethnicity an appropriate measure of health care marginalization? A systematic review and meta-analysis of the outcomes of diabetic foot ulceration in Aboriginal populations

BACKGROUND: Aboriginal people have higher prevalence rates of diabetes than non-Aboriginal people in the same geographic locations, and diabetic foot ulcer (DFU) complication rates are also presumed to be higher. The aim of this systematic review and meta-analysis was to compare DFU outcomes in Aboriginal and non-Aboriginal populations. METHODS: We searched PubMed, Embase, CINAHL and the Cochrane Library from inception to October 2018. Inclusion criteria were all types of studies comparing the outcomes of Aboriginal and non-Aboriginal patients with DFU, and studies from Canada, the United States, Australia and New Zealand. Exclusion criteria were patient age younger than 18 years, and studies in any language other than English. The primary outcome was the major amputation rate. We assessed the risk of bias using the ROBINS-I (Risk Of Bias In Non-randomized Studies – of Interventions) tool. Effect measures were reported as odds ratio (OR) with 95% confidence interval (CI). RESULTS: Six cohort studies with a total of 244 792 patients (2609 Aboriginal, 242 183 non-Aboriginal) with DFUs were included. The Aboriginal population was found to have a higher rate of major amputation than the non-Aboriginal population (OR 1.85, 95% CI 1.04–3.31). Four studies were deemed to have moderate risk of bias, and 2 were deemed to have serious risk of bias. CONCLUSION: Our analysis of the available studies supports the conclusion that DFU outcomes, particularly the major amputation rate, are worse in Aboriginal populations than in non-Aboriginal populations in the same geographic locations. Rurality was not uniformly accounted for in all included studies, which may affect how these outcome differences are interpreted. The effect of rurality may be closely intertwined with ethnicity, resulting in worse outcomes.