The Prevalence and Incidence of Lower Extremity Amputation in a Diabetic Population

OBJECTIVE: To describe the incidence of lower extremity amputations and sores or ulcers and investigate risk factors for these complications. DESIGN: Cohort. SETTING: Primary care. PARTICIPANTS: Population-based sample (N = 1210) of younger-onset diabetic persons (diagnosed before age 30 years and taking insulin) and a stratified random sample (N = 1780) of older-onset diabetic persons (diagnosed after age 30 years). Baseline and 4-year follow-up examinations were completed by 996 and 891 younger-onset persons, respectively, and by 1370 and 987 older-onset persons, respectively. MAIN OUTCOME MEASURES: Amputations and sores or ulcers of the lower extremities. RESULTS: Four-year incidence of amputations was 2.2% in both groups. Incidence of sores or ulcers was 9.5% in younger-onset and 10.5% in older-onset persons. In younger-onset persons, significant risk factors for amputation with odds ratios (and 95% confidence intervals) include age, 2.0 for 10 years (1.2 to 3.1), history of sores or ulcers, 10.5 (3.7 to 29.8), diastolic blood pressure, 2.1 for 10 mm Hg (1.3 to 3.5), and pack-years smoked, 1.3 for 10 years (1.0 to 1.6). Risk factors for sores or ulcers include glycosylated hemoglobin, 1.6 for 2% (1.3 to 2.0), retinopathy, 1.3 for two steps (1.1 to 1.6), and current smoking, 2.3 (1.0 to 5.6). In older-onset persons, risk factors for amputation are history of sores or ulcers, 4.6 (1.7 to 12.2), proteinuria, 4.3 (1.6 to 11.5), glycosylated hemoglobin, 1.5 for 2% (1.0 to 2.2), sex, 2.8 for males (1.0 to 7.5), and duration of diabetes, 1.8 for 10 years (1.0 to 3.2). For sores or ulcers, risk factors are glycosylated hemoglobin, 1.6 for 2% (1.3 to 2.0), duration, 1.5 for 10 years (1.0 to 2.1), proteinuria, 2.2 (1.1 to 4.3), and diastolic blood pressure, 0.8 for 10 mm Hg (0.6 to 1.0). CONCLUSIONS: Several factors offer potential for modification for the prevention of amputations but require further study. These include blood pressure, glycosylated hemoglobin, and smoking.