Abstract 15232: Lifetime Risk of Nontraumatic Lower-extremity Amputation: The Atherosclerosis Risk in Communities Study

Abstract

Introduction: Nontraumatic lower-extremity amputation is a serious clinical outcome. Major risk factors include peripheral artery disease and diabetic neuropathy. Although incidence rates of amputation have been reported, no lifetime risk estimates are available. Hypothesis: The lifetime risk of amputation is higher in men, blacks, and those of low socioeconomic status (SES). Methods: In 15,744 ARIC participants aged 45-64 at baseline (1987-89), we estimated the lifetime risk of amputation through age 80 by race-sex and race-SES using Fine and Gray’s proportional subhazards model accounting for the competing risk of death. This method is optimal for time-fixed exposures and thus our primary exposures are sex and race. SES included education, annual family income, and the Area Deprivation Index linked to census tract geocoding. Non-traumatic amputation was identified from hospitalization ICD codes (e.g., 84.1, Z89.4) and related operation codes. Results: There were 253 non-traumatic amputations during a median follow up of 29 years. Lifetime risk of amputation at age 80 was highest in black men (4.6%), followed by black women (2.8%), white men (1.1%) and white women (0.7%) ( Figure ). Blacks of low SES showed the highest lifetime risk (4.5%). Blacks with high SES had a higher lifetime risk of amputation than whites with low SES. The pattern was consistent when we investigated each of education (≤ vs. > high school), income (< vs. ≥$25,000) and Area Deprivation Index (< vs. ≥ race-specific median), separately. Conclusions: In this population-based cohort 5% of black men and 3% of black women experienced a non-traumatic amputation during their lifetime, while only 1% of white men and women had a hospitalization for amputation. The lifetime risk was higher among those with lower SES in both race groups. Future public health and primary care efforts should emphasize risk factor management (e.g., diabetes and smoking) among racial minority groups and those with low SES.