The Impact of Obesity in Patients Undergoing Robotic Partial Nephrectomy

Abstract

Introduction: As the prevalence of obesity increases worldwide, an increasing proportion of surgical candidates have an elevated body mass index (BMI), with associated metabolic syndrome. Yet there exists limited evidence regarding the effect of elevated BMI on surgical outcomes in robotic surgeries. We examined whether obese patients had worse perioperative outcomes and postoperative renal function after robotic partial nephrectomies (RPNs). Materials and Methods: We performed a multi-institutional analysis of 1770 patients who underwent RPNs between 2008 and 2015, allowing time for the data set to mature. Associations between BMI, as a continuous and categorical variable, and perioperative outcomes, acute kidney injury (AKI, >25% reduction in estimated glomerular filtration rate [eGFR]) at discharge, and change in eGFR per month were analyzed. AKI and eGFR were evaluated using multivariable logistic and linear regression models adjusted for confounders, including age, Charlson comorbidity index, tumor size, and the identity of the surgeon. Results: In total 45.2% (n = 529) of patients were found to be obese, with a greater prevalence of hypertension and diabetes in overweight and obese patients. Obese patients were more likely to have malignant tumors (>77% vs 68%, p < 0.001) and trended toward having larger tumors (3.0 cm vs 2.8 cm; p = 0.061). Heavier patients required longer operative times (166-196 minutes vs 155 minutes; p < 0.001), although equivalent warm ischemia times (p = 0.873). Obesity did not correlate with an increased complication rate (p > 0.05). On multivariable analysis, obesity (odds ratio [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 at discharge. BMI above normal weight was not associated with greater eGFR decline per month post-RPN. Conclusions: Obesity was associated with equivalent perioperative outcomes and long-term renal function. Further research is warranted into how obesity and metabolic syndrome may foster a more aggressive tumor environment. RPN appears to be an equally safe operative option for patients regardless of obesity status.

Differential effects of obesity on perioperative outcomes in renal cell carcinoma patients based on race and ethnicity and neighborhood-level socioeconomic status

“…Our findings on impacts of obesity on EBL and length of hospital stay were consistent with literature showing that obesity increases blood loss during partial nephrectomy but no effect on length of hospital stay ( 16 - 20 ). However, unlike our study, previous studies focused on evaluating safety of minimally invasive surgical approach (laparoscopic or robotic partial nephrectomy) among obese patients and found no association between obesity and warm ischemia time ( 18 - 20 ).…”

“…Obesity and metabolic disorders, however, may complicate the surgical procedure leading to poor perioperative outcomes. In particular, prior studies of partial nephrectomy have shown that obesity increase ischemia time ( 16 ), estimated blood loss (EBL) ( 16 - 19 ), acute kidney injury ( 20 ), and rate of conversion to open surgery ( 21 ). Studies in patients who underwent laparoscopic radical nephrectomy have also shown that obesity increases operative time ( 22 ), rate of conversion to open surgery ( 23 ), and length of hospital stay ( 24 ).…”

The impact of body mass index on oncological and surgical outcomes of patients undergoing nephrectomy: a systematic review and meta‐analysis

“…Our finding is similar to other studies consisting of gastroenterological cancer surgery, colorectal cancer surgery, and liver surgery, in which they have also shown that obesity prolongs operative time [23]. This is likely a result of thicker abdominal walls and perinephric fat, which result in slower dissection and poses unique intraoperative challenges [24,25]. However, the clinical significance of a mean difference of 22 min may be questionable.…”

Evaluation of Renal Function after Partial Nephrectomy and Detection of Clinically Significant Acute Kidney Injury

“…Results of multivariable analysis show that 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 at discharge. BMI above normal weight was not associated with greater eGFR decline per month post-RPN [ 33 ]. Another study by Martini et al showed that in the AKI group there were more patients with increased BMI, 31.3 (26.6, 36.4) vs. 29.0 (25.7, 34.0), p < 0.001.…”