Objective: To describe the 10-year cumulative incidence of and risk factors for lower-extremity amputations in diabetics.
Design: Cohort study.
Setting: Primary care.
Participants: Population-based sample (N = 879) of younger-onset diabetic persons (in whom diabetes was diagnosed before 30 years of age and who were taking insulin) and a stratified random sample (N = 956) of older-onset diabetic persons (diagnosis at or after 30 years of age) participating in baseline, 4-year, and 10-year examinations.
Main outcome measure: Amputations of the lower extremities as reported by the participants.
Results: The 10-year cumulative incidence of lower-extremity amputation was 5.4% in younger-onset and 7.3% in older-onset persons. Multivariate analyses were performed by logistic regression. In younger-onset persons, age (odds ratio [OR] for 10 years, 2.0; 95% confidence interval [CI], 1.5-2.8), history of ulcers (OR,4.8; 95% CI, 2.3-9.9), diastolic blood pressure (OR, 2.1 for 10 mm Hg; 95% CI, 1.5-3.0), glycosylated hemoglobin level (OR, 1.4 for 1%; 95% CI, 1.2-1.6), sex (OR, 5.2 for men; 95% CI, 2.2-12.3), and retinopathy (OR, 1.2 for 2 steps; 95% CI, 1.1-1.4) were significantly associated with incidence of lower-extremity amputation. In older-onset persons, history of ulcers (OR, 3.3; 95% CI, 1.6-6.8), glycosylated hemoglobin level (OR, 1.3 for 1%; 95% CI, 1.1-1.5), duration of diabetes (OR, 1.6 for 10 years; 95% CI, 1.1-2.5), sex (OR, 2.6 for men; 95% CI, 1.3-4.9), diastolic blood pressure (OR, 0.7 for 10 mm Hg; 95% CI, 0.5-1.0), and proteinuria (OR, 2.4; 95% CI, 1.0-5.7) were significantly associated with incidence of lower-extremity amputation.
Conclusion: These data show there are several risk factors for lower-extremity amputation with potential for modification and preventive strategies.