Incidence and predictors of recurrent and other new diabetic foot ulcers: a retrospective cohort study.

Aims: To estimate progression rates, evaluate risk factors for progression, and study rate ratios for progression among people with a healed diabetic foot ulcer according to whether the healed ulcer was neuropathic, neuro-ischaemic or critically ischaemic.

Methods: We conducted a retrospective cohort study in all individuals with a healed diabetic foot ulcer treated at the Steno Diabetes Centre Copenhagen foot clinic in the period 2010 to 2016. The outcome of interest was recurrent/other new diabetic foot ulcers.

Results: A total of 780 people had a healed diabetic foot ulcer in the study period (2010-2016). The participants were followed for 1249 person-years [median (Q1-Q3) 1.04 (0.38-2.46) person-years] in total. One-third (33.1%) developed a recurrent/other new diabetic foot ulcer per year. Male gender, people with Type 2 diabetes and smokers had a statistically significantly higher risk of progression to a recurrent/other new diabetic foot ulcer compared to participants without these risk factors. Participants with neuro-ischaemic or critically ischaemic diabetic foot ulcers had statistically significantly higher progression rates than participants with neuropathic diabetic foot ulcers.

Conclusions: Focus should be on preventing future recurrent/other new diabetic foot ulcers especially in people with ischaemia.