Diabetes mellitus is the major risk factor for African Americans who undergo peripheral bypass graft operation

Objective: African Americans, especially African American women, have a greater risk of lower extremity ischemia that necessitates an infrainguinal bypass graft operation and amputation. Because the prevalence of diabetes mellitus is proportionally greater in this ethnic/racial group, the relative contribution of diabetes was compared with other potential risk factors. Methods: This study was designed as a retrospective case control study at the University and Veterans Hospitals. In a 5-year period, 764 consecutive patients who required infrainguinal revascularizations were compared with a Statewide population that was described by the 1995 Behavior Risk Factor Surveillance System database. The main outcome measure was the requirement for infrainguinal revascularization. Results: Diabetes mellitus was more common among African American women who underwent bypass graft operation (70%; odds ratio [OR], 24.9; 95% confidence interval [CI], 20.3 to 30.4) than African American men (46%; OR, 11.6; 95% CI, 8.9 to 15.2), white women (49%; OR, 15.9; 95% CI, 13.0 to 19.5), or white men (42%; OR, 14.8; 95% CI, 12.5 to 17.4). Overall, bypass graft operation was associated more strongly with diabetes mellitus for all groups (OR 15.7; 95% CI, 13.5 to 18.3) than with smoking (OR, 4.5; 95% CI, 3.8 to 5.2) or hypertension (OR, 4.6; 95% CI, 4.0 to 5.3). Life-table analysis revealed limb salvage to be worse at 3 pears among African American patients (64% vs 75%; P < .005) despite similar primary and cumulative secondary graft patency rates. Conclusion: Diabetes mellitus is the dominant risk factor that contributes to the need for bypass graft operation, especially among African American women. A greater prevalence of diabetes mellitus may account for the higher incidence of tissue necrosis and the increased requirement for distal bypass grafting and may contribute to the reduction in long-term limb salvage that was observed with these women.