A study of male veterans with diabetes has found that incidence of diabetic foot ulcer (DFU) is the most powerful independent risk factor for lower‐extremity amputation, representing roughly a tenfold increase in amputation risk beyond other limb and systemic risk factors.
The prospective Seattle diabetic foot study looked at 1,458 veterans with diabetes, with 2,893 ulcer-free lower limbs at baseline.
The cohort was followed from 1990 to 2002, with a mean follow-up of 4.9 years. Repeated 12 to 18‑month evaluations collected demographic, clinical, biochemical, and detailed neurovascular limb-level measures including ABI, lower‐limb transcutaneous oxygen pressure, neuropathy and Charcot deformity. Incidence of DFU and lower-extremity amputation was also assessed.
Over follow-up, 227 incidents of DFUs (7.8% of limbs) were reported, and 72 lower-extremity amputations (2.5% of limbs; 5.1/1000 limb-years) occurred. There were 64 amputations (about 89%) preceded by an incident of DFU.
A key finding was that Kaplan-Meier and hazard function plots showed a sharp rise in amputation hazard in approximately the first 500 days after DFU occurrence, with persistently elevated risk thereafter, whereas hazard remained relatively stable in limbs without DFU.
The study authors concluded: “Preventing DFU occurrence and ensuring timely, effective ulcer healing are likely to result in the greatest reductions in diabetes-related amputations, particularly when integrated with aggressive management of peripheral arterial disease, renal impairment, and blood pressure.”
They commented: “We have to acknowledge that the cohort consists almost exclusively of older male veterans with predominantly type 2 diabetes from a single centre, limiting generalisability of the results, especially to women, younger individuals and other clinical-social settings.
“Further, changes in diabetic foot care since the 1990 may attenuate some associations and could add a limit to direct applicability to contemporary practice.
“However, in conclusion, this long prospective study highlights how early detection and treatment of DFU is paramount to prevent LEA.”
Read the full study, Association of Incident Diabetic Foot Ulcer With Lower-Extremity Amputation Risk: The Prospective Seattle Diabetic Foot Study, here.
