O20 – Hypoalbuminemia in Obese Surgical Patients is Disproportionately Associated With Infectious Complications

Author(s):

Zachary Dietch, Christopher Guidry, Timothy McMurry, Rhett Willis, Stephen Davies, Robert Sawyer, University of Virginia

Background: Protein-calorie deficiency (PCD) is a known risk factor for surgical complications, including surgical infections; however, the risks of PCD by weight class have not been well described.

Hypothesis: We hypothesized that the combination of obesity and PCD is associated with increased surgical complications, including surgical infections, compared to normal weight patients.

Methods: 89,718 general surgery patients undergoing elective operations within the 2011 National Surgical Quality Improvement Program were analyzed. Patients with conditions that could potentially confound serum albumin (SA) were excluded. Patients were stratified by normal (>3.0 g/dl) versus low (<3.0 g/dl) SA. The relative impact of SA and BMI (as individual and as combined variables) on surgical morbidity and mortality were assessed. Multivariate analyses were performed to identify independent risk factors for morbidity (overall and infectious) and mortality.

Results: Overall, 2,933 (3.27%) of patients had low preoperative SA. 803 (27.4%) patients with low preoperative SA were obese (BMI >30), versus 40,351 (46.5%) with normal preoperative SA. Importantly, the interaction of hypoalbuminemia and BMI was independently associated with infectious complications among hypoalbuminemic patients with BMI>35, and mortality for patients with BMI>30 (Table 1) after controlling for appropriate demographics, comorbidities, surgical wound classification, operation type and complexity (c-statistic: 0.768 and 0.874 respectively).

Conclusions: PCD and hypoalbuminemia among obese surgical patients are associated with significantly increased morbidity and mortality compared to lean comparators. Paradoxically, malnutrition may be less easily recognized in obese individuals and surgeons may need to more carefully evaluate this population prior to surgery. Future studies should investigate therapy to correct PCD specifically among obese patients prior to surgery.