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

Background: Obesity is a well-established risk factor of renal cell carcinoma (RCC), however the impact of obesity on surgical outcomes for racial and ethnic minority patients with RCC is unclear. This study investigated whether a higher body mass index (BMI) or obesity (BMI ≥30 kg/m²) was associated with worse perioperative outcomes and if there were heterogeneous effects based on race, ethnicity, and neighborhood-level socioeconomic factor.

Methods: In this single-center cross-sectional study, medical records of patients who underwent partial or radical nephrectomy between 2010 and 2022 were retrospectively reviewed. Logistic regression analysis was performed to assess associations of BMI and perioperative outcomes [ischemia time, estimated blood loss (EBL), and length of hospital stay].

Results: A total of 432 patients, including 49.8% non-Hispanic White (NHW), 35.0% Hispanic, and 6.9% American Indian (AI) patients, were included. Median [interquartile range (IQR)] BMI was 30.2 (26.3-35.2) kg/m², and Hispanic (31.5) and AI (32.5) patients had higher median BMI than NHW (29.1) patients (P=0.006). Median ischemia time, EBL, and length of hospital stay were 18.5 (IQR, 15.0-22.4) minutes, 150 (IQR, 75.0-300.0) mL, and 3 (IQR, 2-5) days. BMI ≥35 kg/m² was associated with a longer ischemia time [>18.5 minutes; odds ratio (OR), 5.17; 95% confidence interval (CI): 1.81-14.76; P=0.002], and the association was stronger in NHW than Hispanic patients (BMI continuous OR, 1.13; 95% CI: 1.04-1.22; P=0.004 in NHW and OR, 1.07; 95% CI: 0.98-1.17; P=0.12 in Hispanics). Class I and II/III obese patients had over two-fold increased odds of a larger EBL (>150 mL) than patients with normal weight (OR, 2.17; 95% CI: 1.03-4.59; P=0.04 for class I and OR, 2.24; 95% CI: 1.04-4.84; P=0.04 for class II/III obese patients). This association was stronger in patients from neighborhoods with high social deprivation index (SDI) and in NHW patients (BMI ≥30 vs. <30 kg/m², OR, 3.53; 95% CI: 1.57-7.97; P=0.002 in high SDI neighborhoods and OR, 2.38; 95% CI: 1.10-5.14; P=0.03 in NHW). BMI was not associated with a longer hospital stay.

Conclusions: In this study, obesity increased likelihood of worse perioperative outcomes, and the associations varied based on race and ethnicity and neighborhood-level socioeconomic factors.