Racial/Ethnic Disparities in Amputation and Revascularization: The Roles of Socioexonomic Reighborhood Stress and Allostatic Load

Abstract

Blacks are several times more likely to undergo a leg amputation as compared to Whites. This is because while peripheral artery disease (PAD), the most common cause of amputation, is more likely to be treated by revascularization (restoration of blood flow) in Whites, PAD is more likely to be treated by amputation in Blacks. Whereas an ongoing debate argues as to whether this disparity is primarily a sociologic versus a biologic phenomenon, I proposed that there are socioeconomic neighborhood stressors that create more severe PAD and renders individuals less likely to undergo successful revascularization and more likely to undergo amputation. Three specific aims are addressed in this dissertation resulting in three manuscripts. In Study 1, utilizing the Nationwide Inpatient Sample Database (NIS) in a retrospective study design, I determined that among patients admitted to the hospital for severe PAD, low socioeconomic status (SES) correlates positively with the likelihood of amputation, but paradoxically correlates negatively with the severity of PAD. In Study 2, I used the National Health and Nutrition Examination Survey, in a cross-sectional study design, to evaluate if there was a relationship between PAD severity, as determined by the ankle-brachial index (ABI) and the level of allostatic load. I did not identify an association. In Study 3, I employed the Nationwide Readmission Databases to show that low SES positively correlates with readmission for amputation following surgical revascularization. Findings from these three papers indicate that there is a positive correlation between low SES and the likelihood of amputation both upon initial admission as well as during subsequent follow up after surgical revascularization. I was unable to establish a clear relationship between PAD severity and allostatic load. The paradoxical finding that low SES individuals present with less severe manifestation of PAD signifies that there are yet-to-be-established factors involved in this complex disparity. This dissertation underscores the dominant role of social determinants of health and submits that in order to adequately address this amputation-revascularization disparity and avoid unnecessary amputations, major investments need to be made not only in healthcare, but also in America’s social infrastructure.