Causation Research on Diabetic Foot Complications—What I Learned From Roger Pecoraro: The 2021 Roger E. Pecoraro Award Lecture

Roger Pecoraro made important contributions to diabetic foot research and is primarily responsible for instilling in me an interest in these complications. Our collaboration in the final years of his life led to the development of the Seattle Diabetic Foot Study. At the time it began, the Seattle Diabetic Foot Study was perhaps unique in being a prospective study of diabetic foot ulcer conducted in a nonspecialty primary care population of patients with diabetes and without foot ulcer. Important findings from this research include the demonstration that neurovascular measurements, diabetes characteristics, past history of ulcer or amputation, body weight, and poor vision all significantly and independently predict foot ulcer risk. A prediction model from this research that included only readily available clinical information showed excellent ability to discriminate between patients who did and did not develop ulcer during follow-up (area under the receiver operating characteristic curve [AUROC] 0.81 at 1 year). Identification of limb-specific amputation risk factors showed considerable overlap with those risk factors identified for foot ulcer but suggested arterial perfusion as playing a more important role. Risk of foot ulcer in relation to peak plantar pressure estimated at the site of the pressure measurement showed a significant association over the metatarsal heads, but not other foot locations, suggesting that the association between pressure and this outcome may differ by foot location. The Seattle Diabetic Foot Study has helped to expand our knowledge base on risk factors and potential causes of foot complications. Translating this information into preventive interventions remains a continuing challenge.