Association between socioeconomic position and diabetic foot ulcer outcomes: a population-based cohort study in South Korea

Background Low socioeconomic position (SEP) is associated with a high incidence of diabetic foot ulcers (DFUs). However, reports on the association between SEP and DFU outcomes are limited. Therefore, in this study, we investigated this association and determined the prognostic factors of DFU outcomes. Methods The total cohort comprised 976,252 individuals. Using probability sampling, we randomly selected a sample of patients by reviewing the data from the Health Insurance Review and Assessment Service database of South Korea during 2011-2015. Residence, household income, and insurance type represented SEP. The primary outcome was amputation, and the secondary outcome was mortality. A multivariate model was applied to identify the predictive factors. Amputation-free survival and overall survival were calculated using the Kaplan-Meier method. Results Among 976,252 individuals in the cohort, 1362 had DFUs (mean age 62.9 +/- 12.2 years; 42.9% were women). Overall amputation and mortality rates were 4.7 and 12.3%, respectively. Male sex (hazard ratio [HR], 2.41; p < 0.01), low SEP (HR 5.13, 5.13; p = 0.018), ophthalmopathy (HR, 1.89; p = 0.028), circulatory complications (HR, 2.14; p = 0.020), and institutional type (HR, 1.78; p = 0.044) were prognostic factors for amputation. Old age (HR, 1.06; p < 0.01), low SEP (HR, 2.65; p < 0.01), ophthalmopathy (HR, 1.74; p < 0.01), circulatory complications (HR, 1.71; p < 0.01), and institution type (HR 1.84; p < 0.01) were predictors of mortality. Conclusions DFU patients with a low SEP are strongly associated with increased amputation and mortality rates. Along with age and comorbidities, SEP could provide the basis for risk assessment of adverse outcomes in DFU. Providing targeted care for this population considering SEP may improve the prognosis.