Risk factors associated with adverse outcomes in a population-based prospective cohort study of people with their first diabetic foot ulcer.

AIMS/HYPOTHESIS: The aim of this study was to determine which clinic-based measures of diabetes and foot status at baseline were associated with adverse outcomes 18 months later in people with diabetes presenting with their first foot ulcer.

SUBJECTS AND METHODS

This was a prospective population-based cohort study of adults with type 1 and type 2 diabetes mellitus presenting with their first foot ulcer (excluding those with severe ischaemia, ankle brachial pressure index <0.5). The main explanatory variables were age, sex, smoking status, ulcer site (dorsal or plantar), size and severity of ulcer, severity of neuropathy, ischaemia, glycosylated haemoglobin, presence of micro- and macrovascular complications, and depression. The main outcomes recorded were death, amputation and recurrence of ulceration, and the time taken for each outcome to occur.

RESULTS

Two hundred fifty-three people were recruited. There were 40 deaths (15.8%), 36 amputations (15.5%), and 99 recurrences (43.2%) at 18 months. Our main findings were that being older [hazard ratio (HR) 1.07, 95% CI 1.04-1.11], having lower glycosylated haemoglobin (HR 0.73, 95% CI 0.56-0.96), moderate ischaemia (HR 2.74, 95% CI 1.46-5.14), and depression (HR 2.51, 95% CI 1.33-4.73) were associated with mortality. Ulcer severity was the only explanatory factor significantly associated with amputation (HR 3.18, 95% CI 1.53-6.59). Microvascular complications were the only explanatory factor associated with recurrent ulceration (HR 3.34, 95% CI 1.17-9.56).

CONCLUSIONS/INTERPRETATION: Commonly used primary and secondary care clinic-based measures could provide the basis for a risk assessment tool for adverse outcomes following first presentation of diabetic foot ulcers.