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 1 0 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 1 0 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.