Background: The relationship between body mass index (BMI) and demographic/clinical characteristics of patients undergoing bariatric surgery is poorly characterized. BMI is often used to characterize patient risk in bariatric surgery. However, its relationship with other risk factors has not been well characterized.
Methods: The Longitudinal Assessment of Bariatric Surgery-1 was a study of the 30-day outcomes in patients undergoing bariatric procedures at 10 clinical centers in the United States. The sample for this study included participants with a BMI > or =40 kg/m(2) and no history of undergoing a bariatric procedure from March 1, 2005 to March 26, 2007. This analysis examined the relationships between BMI strata and several demographic/clinical characteristics.
Results: Of 2559 patients (23% male, 10% black, 9% age > or =60 yr) with a BMI of > or =40 kg/m(2), 29% had a BMI of 50 to <60 kg/m(2) and 12% a BMI of > or =60 kg/m(2). The percentage of men and blacks increased with greater BMI category and the percentage of older patients (age > or =60 yr) decreased. Patients with a greater BMI were more likely to have a history of several co-morbid conditions (hypertension, diabetes, congestive heart failure, asthma, poor functional status, sleep apnea, pulmonary hypertension, venous thromboembolism, or venous edema with ulcerations) than were patients with a BMI of 40-50 kg/m(2) after adjusting for age, race, sex, and ethnicity.
Conclusion: A greater BMI was associated with several patient characteristics that have been linked to less weight loss, more adverse outcomes, and increased healthcare use in previous studies. Outcomes analyses should consider the potential for the confounding of BMI with demographic and clinical characteristics.