Peripheral bypass surgery and amputation: northern Illinois demographics, 1993 to 1997.

HYPOTHESIS: This study tests whether age, sex, income, and racial differences predict rates of aortoiliac and femorodistal bypass surgery and above- and below-knee amputation for residents of northern Illinois from 1993 to 1997.
DESIGN: A hospital discharge survey study describing standardized procedure rates and the odds of undergoing amputation vs bypass procedures for specified sociodemographic populations. Multiple logistic regression was used to compare the odds of undergoing major amputation vs bypass surgery controlling for the prevalence of diabetes, gangrene, high-risk comorbid conditions, and treatment at major area teaching hospitals.
RESULTS: Between 1993 and 1997, 19,250 study procedures were performed during 18,603 admissions at 105 Illinois hospitals. The mean annual major amputation rate per 100,000 was 20.77; femorodistal and aortoiliac bypass rates were 24.26 and 4.70, respectively. Significantly higher odds (between 1.14 and 1.36) of undergoing amputation were found for low-income areas and ZIP codes with large and medium African American populations. Severe comorbidity, diabetes, and especially gangrene (odds ratio, 12.9) predicted amputation, while treatment at a major teaching hospital and male sex predicted a higher odds of undergoing bypass procedures.
CONCLUSIONS: Results are consistent with unmeasured racial and income differences in the severity of atherosclerosis (or related risk factors such as smoking, diet, and exercise), barriers to timely primary care, or selective referral of lower-income and African American patients to hospitals with less vascular surgery capacity. These findings imply a particular need to identify and review the quality of care for patients undergoing primary lower-extremity amputations.