The effect of income and insurance on the likelihood of major leg amputation

Background: Although it has been suggested that individuals of low socioeconomic status and those with Medicaid or no insurance may be more likely to have their peripheral artery disease treated by leg amputation rather than by limb-saving revascularization, it is not clear if this disparity occurs consistently on a national basis, and if it does so in a linear fashion, such that poorer individuals are at progressively greater risk for amputation. Objective: We undertook this study to determine if lower median household income and Medicaid/no insurance status are associated with a higher risk for amputation, and if this occurs in a progressively linear fashion. Methods: The National (Nationwide) Inpatient Sample Database was queried to identify patients who were admitted with a diagnosis of critical limb ischemia from 2005 to 2014 and underwent either a major amputation or a revascularization procedure during that admission. Patients were stratified according to their insurance status and their median household income into four income quartiles. Multivariate logistic regression was performed to determine the effect of income and insurance status on the odds of undergoing amputation vs leg revascularization. Results: Across the different insurance types, there was a significant decrease in the odds ratios for amputation as one progressed from one MHI quartile to a higher one: namely, Medicare (2.23, 1.87, 1.65, and 1.42 for the first, second, third, and fourth MHI quartiles); Medicaid (2.50, 2.28, 2.04, and 1.80 for the first, second, third, and fourth MHI quartiles); private insurance (1.52, 1.21, 1.16, and 1.00 for the first, second, third, and fourth MHI quartiles), and uninsured (1.91, 1.64, 1.10, and 1.22, for the first, second, third, and fourth MHI quartiles). Conclusions: Lower MHI, Medicaid insurance, and uninsured status are associated with a greater likelihood of amputation and a lower likelihood of undergoing limb-saving revascularization. These disparities are exacerbated in stepwise fashion, such that lower income quartiles are at progressively greater risk for amputation.