The 14-year incidence of lower-extremity amputations in a diabetic population - The Wisconsin Epidemiologic Study of Diabetic Retinopathy

OBJECTIVE - To estimate the cumulative 14-year incidence of lower-extremity amputations (LEAs) and evaluate risk factors for LEA. RESEARCH DESIGN AND METHODS - Study subjects consisted of population-based cohorts of younger-onset (diagnosed before age 30 years and taking insulin, n = 906) and older-onset (diagnosed after age 30 years, n = 984) individuals with diabetes. Subjects participated in baseline (1980-1982), 4-year, 10-year and 14-year examinations or interviews. LEAs were determined by history. RESULTS - The cumulative 14-year incidence of LEA was 7.2% in younger- and 9.9% in older-onset patients. In multivariable analyses based on the discrete linear logistic model, LEA in the younger-onset group was more likely for males (odds ratio [OR] 5.21 [95% CI 2.50-10.88]), older age (OR for 10 years 1.71 [1.30-2.24]), higher glycosylated hemoglobin (OR for 1% 1.39 [1.22-1.59]), higher diastolic blood pressure (OR for 10 mmHg 1.58 [1.20-2.07]), history of ulcers of the feet (3.19 [1.71-5.95]), and more severe retinopathy (OR for one step 1.16 [1.08-1.24]). In younger-onset patients aged greater than or equal to 18, pack-years smoked (OR for 10 years 1.20 [1.03-1.41]) was also associated with LEAs, and daily aspirin use was inversely associated (OR 0.11 [0.01-0.83]). In the older-onset group, LEA was more likely for men (2.66 [1.49, 4.76]) and if the subject had higher glycosylated hemoglobin (OR for 1% 1.25 [1.09-1.43]), higher pulse pressure (OR for 10 mmHg 1.19 [1.04-1.37]), history of ulcers (3.56 [1.84-6.89]), and more severe retinopathy (OR for one step 1.07 [1.00-1.13]). CONCLUSIONS - There are several risk factors for LEA with potential for modification and preventive strategies.