Contribution of body mass index to postoperative outcome in minority patients

OBJECTIVE: The purpose of this investigation was to examine the association of body mass index (BMI) category with short-term outcomes in minority surgical patients-a relationship that previously has not been well characterized. METHODS: Data from the National Surgical Quality Improvement Program were used to calculate the BMI of minority patients undergoing surgery from 2005 to 2008. Patients were stratified into 5 BMI classes. Stepwise logistic regression was used to calculate odds ratios for mortality after controlling for known clinically relevant covariates. MAIN OUTCOME MEASURES: Morbidity and mortality at 30 days, across all 5 BMI classes. RESULTS: Among 119,619 minority patients studied, 50% were African American, 36% Hispanic, 10% Asian and Pacific Islanders, and 4% American Indian and Alaskan natives. Seventy percent were overweight or obese. Women were more likely to be obese or severely obese. The overall mortality rate was 1.5%, and this varied significantly by BMI class. Distribution of 30-day mortality demonstrated a progressive decrease, with the highest risk of death in the underweight class, and the lowest risk of death in the severely obese class. This relationship was maintained, even in patients with at least 1 major postoperative complication. CONCLUSION: The prevalence of being overweight or obese was high in this nationally representative cohort of minority surgical patients. Although BMI class is a significant predictor of 30-day mortality, the effect appeared paradoxical. The poorest outcomes were in the underweight and normal BMI patients. Severely obese patients had the lowest risk of mortality, even after experiencing a major postoperative complication.