Presentation Authors: Daniel C. Rosen, Muthumeena Kannappan*, Yong Kim, David J Paulucci, Alp T. Beksac, New York, NY, Ronney Abaza, Columbus, OH, Daniel D. Eun, Philadelphia, PA, Akshay Bhandari, Miami Beach, FL, Ashok K. Hemal, Winston-Salem, NC, James Porter, Seattle, WA, Ketan K. Badani, New York, NY
Introduction: As the prevalence of obesity dramatically increases worldwide, an increasing proportion of surgical candidates have an elevated Body Mass Index (BMI), with associated metabolic syndrome, diabetes, and hypertension. Yet whether these patients have worse perioperative outcomes is controversial. We examined whether obese patients had worse perioperative and postoperative renal function outcomes following robotic partial nephrectomies (RPN).
Methods: We used a multi-institutional database to identify 1,770 patients with 2 kidneys that underwent RPN from 2008-2015 by six high volume surgeons. The association of BMI with perioperative outcomes and acute kidney injury at discharge (AKI, >25% reduction in eGFR), and change in eGFR per month (Range 3-24 months) post-RPN was evaluated. BMI was analyzed as a continuous and categorical variable using Center for Disease Control (CDC) groups. AKI at discharge was analyzed using multivariable logistic regression models and eGFR over time was evaluated using multivariable linear mixed effects models; both of which were adjusted for confounding variables including age, Charlson-comorbidity index, tumor size, and the operating surgeon.
Results: 45.2% (n=529) of patients were found to be obese, with a greater prevalence of hypertension and diabetes in patients with higher BMI (Table I). Obese patients were more likely to have malignant tumors (p < .001) and trended towards having larger tumors (3.0cm vs 2.8cm; p=0.061). These patients required longer operative times, though equivalent warm ischemia times. Obesity was not correlated with complication rate (p>.05). On multivariable analysis, obesity (OR=1.81; p=0.031), male sex (OR=1.54; p=0.028), and larger tumor size (OR=1.23; p < 0.001) were associated with a significant increase in the likelihood of AKI. BMI above normal weight was not associated with greater eGFR decline per month from 3 to 24 months post-RPN.
Conclusions: Obese patients had more aggressive tumors, but did not demonstrate an increase in complications. Robotic Partial Nephrectomy appears to be an equally safe operative option for patients regardless of BMI.