Body Mass Index and Surgical Outcome in a Puerto Rican Population

To determine the impact of body mass index (BMI) on postoperative morbidity and 30-day mortality in the population served by the University of Puerto Rico (UPR)-affiliated hospitals.

We reviewed the surgical data entered into the UPR General Surgery Department database from January 1, 2014, through June 30, 2016. This database collects patient and procedural information from the UPR-affiliated hospitals. We compared the postoperative morbidity and 30-day mortality rates of 5 different BMI groups: underweight (<18.5 kg/m2), normal weight (18.5-24.9 kg/m2), overweight (25.0-29.9 kg/m2), obese, classes I and II (30-39.9 kg/m2), and morbidly obese (>=40 kg/m2). Multivariable regression analyses, adjusted for age, gender, and surgery type, were used to evaluate the risks for each BMI category.

Information on 9,856 patients was reviewed. The mean age of the sample population was 52 (±20) years; 57% were women and 43% were men. The postoperative morbidity and 30-day mortality rates of the underweight group were significantly higher than those of the normal-weight group (6.1% vs. 3.1% and 2.1% vs. 0.5%, respectively; p<0.001). The morbidly obese also had significantly higher (p<0.001) postoperative morbidity (5.3% vs. 2.1%) and 30-day mortality rates (2.7% vs. 0.5%) compared to normal-weight patients. The odds of 30-day mortality were significantly higher for the underweight (odds ratio [OR], 5.64; 95% confidence interval [CI], 2.47-12.92) and morbidly obese patients (OR, 7.23; 95% CI, 3.01-17.39). The overweight patients had no increased risk, and the obese patients had a slight increase in morbidity (OR, 1.54; 95% CI, 1.08-2.21) but no significant increase in 30-day mortality (p>0.05).

Patients at the extremes of the BMI have more postoperative complications and higher 30-day mortality rates than do patients with mid-range scores.