Ulcer metastasis? Anatomical locations of recurrence for patients in diabetic foot remission

Background The "cancer analogy" is powerful for communicating risk to and organizing care for patients with diabetic foot syndrome. One potentially underappreciated similarity between cancer and foot ulcers is that both can recur at anatomical locations distinct from the primary occurrence, albeit with different physiological mechanisms. Few studies have characterized the location of diabetic foot ulcer recurrence, and these have been limited by considering only the first recurrent wound following a recent-healed wound. We therefore characterized the anatomical locations at which diabetic foot ulcers are likely to recur considering multiple wounds during follow-up and the locations of all prior wounds documented in the participant's history. Methods We completed a secondary analysis of existing data from a 129 participant multi-center study of participants in diabetic foot remission. The primary outcome was plantar foot ulceration, and each participant was followed for 34 weeks or until withdrawing consent, allowing characterization of all wounds occurring. We stratified the anatomical locations of wounds prior to the trial by the following outcome categories during the trial: no recurrence, recurrence to the same anatomical location, recurrence to a different anatomical location on the same foot, and recurrence to the contralateral foot. Results A large percentage (48%) of wounds recurred to the contralateral foot, and the proportion of subsequent foot ulcer to the contralateral limb was largely unaffected by the anatomical location of foot ulcer prior to the study. Only 17% of prior diabetic foot ulcers were followed by recurrence to the same anatomical location. Rates of recurrence remained high during treatment of a wound (0.41 foot ulcer/ulcer-year). Participants had documented wounds to 2.2 distinct anatomical locations on average, and more than 60% of participants had wounds to more than one plantar location by the end of the study. Conclusions Given the significant morbidity, mortality, and resource utilization associated with foot ulcer recidivism, quality and evidenced-based preventive care is essential. Our results better characterize the burden of recurrence and to what anatomy recurrence is most likely. These insights may benefit providers and patients alike for the provision of high-quality preventive care thereby resulting in reduced morbidity, mortality, and cost.