Incidence and risk factors of first-ever diabetic foot ulcers in patients with newly diagnosed type 2 diabetes mellitus

Abstract

Aims: To investigate the long-term incidence of diabetic foot ulcers (DFU) and identify risk factors in a nationwide cohort of patients newly diagnosed with type 2 diabetes mellitus (T2DM). Methods: We conducted a retrospective, population-based cohort study using Korean National Health Insurance Service data. Adults aged >= 20 years newly diagnosed with T2DM between 2009 and 2012, without prior diabetes (2002-2008), were included. Patients with preexisting cardiovascular disease, prior lower-extremity amputation, DFU, or death within 1 year of diagnosis were excluded. Participants were followed up until DFU occurrence, death, or December 31, 2024. Multivariable regression was performed to identify independent risk factors. Age- and sex-based 1:4 propensity score matching was used for comparisons. Results: Among 137,541 patients, 7,599 (5.5%) developed DFU during follow-up. Smoking, non-Seoul residence, statin use, hypertension, dyslipidemia, heart failure, chronic obstructive pulmonary disease, and elevated fasting blood glucose were independently associated with increased DFU risk. Diabetes-related vascular complications were significant predictors. Cumulative DFU incidence was higher in patients with microvascular complications. All-cause mortality did not differ between matched groups. Conclusions: Approximately 5.5% of newly diagnosed T2DM patients developed DFU over 12 years of follow-up. Diabetes-related vascular complications were major determinants, highlighting the need for early risk identification and preventive foot care.