Racial disparity in amputation-free survival after infrainguinal bypass procedure: contribution of socioeconomic status.

Objective: To investigate amputation-free survival after infrainguinal bypass in African Americans and Hispanics compared with non-Hispanic whites and to determine the contribution of socioeconomic status to potential racial disparity.

Design: This is a retrospective cohort study of subjects who underwent infrainguinal bypass due to critical limb ischemia from 1997 through 2004. The primary end point was major amputation or death, whichever occurred first. Neighborhood socioeconomic status obtained from the 2000 United States Census was used as a proxy for an individual's socioeconomic status.

Results: There were 595 subjects (237 non-Hispanic whites, 205 African Americans, 153 Hispanics) in the study. Median amputation-free survival was 1.3, 3.3, and 3.2 yrs among Hispanics, African Americans, and non-Hispanic whites, respectively. Hazard ratio for amputation or death was 1.38 (95% confidence interval, 1.02-1.87) in Hispanics and 0.81 (95% confidence interval, 0.63-1.16) in African Americans compared with non-Hispanic whites after multivariable adjustment. For those residing in their homes, adjusting for socioeconomic status attenuated the hazard ratio in Hispanics to 1.08, explaining 78% of increased hazard.

Conclusions: There was no significant difference between African Americans and non-Hispanic whites in amputation-free survival after infrainguinal bypass. Hispanics were 1.4 times more likely to have amputation or death than non-Hispanic whites, which was largely explained by low socioeconomic status.