Nutritional predictors of perioperative complications and mortality following nephrectomy for renal malignancies: A population-based analysis

Introduction and Objective: Conflicting data exists regarding the impact of body mass index (BMI) on postoperative outcomes following surgery for renal malignancies (RM). Herein, we investigated associations between obesity, hypoalbuminemia, and/or significant weight loss in the preoperative period, and risk complications and mortality within 30 days of radical (RN) or partial nephrectomy (PN). Materials and Methods: Review of the American College of Surgeons National Surgical Quality Improvement Program database identified 8,618 patients treated with PN or RN for RM between 2005 and 2012. Univariate and multivariable logistic regression models were developed to assess associations between hypoalbuminemia (<3.5 g/dl), >10% weight loss within 6 months of surgery, obesity (BMI >30 kg/m²), and 30-day major complications and mortality. Results: Median BMI was 29.2 kg/m² with 24.9%, 11.9%, and 8.2% having class I, II, and III obesity, respectively. Weight loss of >10% was observed in 2.6% and 15.4% had preoperative albumin<3.5 g/dl. There were 1,802 complications (20.9%) and 88 deaths within 30 days (1.0%). On multivariable analysis, BMI ≥40 kg/m² (OR 1.3, p = 0.04), >10% weight loss (OR 1.9, p < 0.001) and hypoalbuminemia (OR 1.5, p < 0.001) were independently associated with 30-day complications, while only >10% weight loss was independently associated with 30-day mortality (OR 2.4, p = 0.03). Conclusions: Extreme obesity, hypoalbuminemia, and significant weight loss were independently associated with risk of significant complications following PN or RN while only significant preoperative weight loss was associated with early mortality, underscoring the need to further understand the utility of moderating these risk factors in the perioperative period.