Return to 2001 Abstacts List

TC Collins, Houston Center for Quality of Care and Utilization Studies, Houston VA Medical Center; M Johnson, Houston Center for Quality of Care and Utilization Studies, Houston VA Medical Center; J Daley, Massachusetts General Hospital/Partners Health Care System; W Henderson, Cooperative Studies Program Coordinating Center, Hines VA Medical Center; SF Khuri, Brockton/West Roxbury VA Medical Center

Objectives: To determine if race/ethnicity is independently associated with an increased risk for non-traumatic lower extremity amputation versus lower extremity bypass revascularization among patients with peripheral arterial disease (PAD).

Methods: Data were analyzed from the National VA Surgical Quality Improvement Program (NSQIP) and from the Veterans Affairs Patient Treatment File (PTF). Data from the NSQIP (Phase I, 10/1/91 - 12/31/93 and Phase II, 8/1/94 - 9/30/95) were used to determine patients who underwent a lower extremity amputation vs. lower extremity bypass revascularization and to obtain information on important preoperative clinical variables, including race, that are likely associated with the outcome of amputation in patients with PAD. The PTF was used to verify that the amputations were associated with a diagnosis of PAD. Race/ethnicity was defined as non-Hispanic White, African American, or Hispanic. Variables that were univariately associated (p <0.05) with the outcome of amputation were then placed into a multivariate logistic regression model to determine independent predictors for the dependent variable, lower extremity amputation vs. lower extremity bypass revascularization.

Results: We identified 3,085 lower extremity amputations and 8,409 lower extremity bypass operations. Among all cases included, there were 416 Hispanics (3.6%), 2,337 African Americans (20.3%), and 8,741 non-Hispanic Whites (76.1%). Among the amputation cases, 4.9% were Hispanic, 29% were African American, and 66.2% were non-Hispanic White. Approximately 11% of patients who underwent an amputation were 50 - 59 years of age, 37% of the patients who underwent an amputation were ages 60 - 69 years, and 48% were > 70 years. Over 99% of all cases were male patients. Risk factors associated with the outcome of lower extremity amputation vs. bypass revascularization were age > 70 years, diabetes mellitus, dialysis, wound infection, rest pain/gangrene, renal insufficiency/failure, history of congestive heart failure, functional status, previous lower extremity bypass revascularization, functional status, emergency surgery, Hispanic ethnicity, and African American race. Among the 18 variables within the model, Hispanic ethnicity and African American race were associated with a greater risk of amputation than a history of diabetes requiring oral medication or rest pain/gangrene (Hispanic ethnicity 1.4, 95% Confidence Interval (CI) 1.1, 1.8; African American race 1.8, 95% CI 1.6, 2.0; diabetes requiring oral medication 1.3, 95% CI 1.1, 1.5; rest pain/gangrene 1.2, 95% CI 1.0, 1.3). The final model had a c-statistic of 0.82.

Conclusions: After adjusting for preexisting illnesses such diabetes, cardiovascular disease, functional status, and other risk factors, both Hispanic ethnicity and African American race are independent risk factors for lower extremity amputation in patients with PAD. Although the burden of certain atherosclerotic risk factors is higher in minority patients, the impact of this burden does not account for the increased risk of the outcome of lower extremity amputation in these two populations. As we do not have information on the severity of disease, race/ethnicity may be a marker for the severity of PAD. Further research is needed to better understand thereason (s) why race/ethnicity is independently associated with poor outcomes in PAD.

Impact: It is important for the Department of Veterans Affairs to better understand why race/ethnicity is an independent marker for poor outcomes in peripheral arterial disease.