Unraveling the BMI paradox in different renal cortical tumors: insights from the INMARC registry

OBJECTIVE

To investigate impact of body mass index (BMI) on survival across different histologies and stages of renal cell carcinoma (RCC).

METHODS

We conducted a retrospective multicenter analysis of clear cell (ccRCC) and non-ccRCC. Obesity was defined according to the WHO criteria (non-Asian BMI >30 Kg/m2, Asian BMI >27.5 Kg/m2). Multivariable analysis (MVA) via Cox regression model was conducted for all-cause (ACM), cancer-specific mortality (CSM) and recurrence.

RESULTS

A total of 3,880 patients with a median follow-up of 31 (IQR 9-64) months were analyzed. Overall, 1,373 (35.3%) were obese; 2,895 (74.6%) were ccRCC and 985 (25.3%) were non-ccRCC (chRCC 246 [24.9%], pRCC 469 [47.6%] and vhRCC 270 [27.4%]). MVA in ccRCC revealed obesity associated with decreased risk of ACM, CSM and recurrence (hazard ratio [HR] 0.80, P = 0.044; HR 0.71, P = 0.039; HR 0.73, P = 0.012, respectively), while in non-ccRCC was not associated with decreased risk of ACM, CSM, and recurrence (P = 0.84, P = 0.53, P = 0.84, respectively). Subset analysis in stage IV ccRCC demonstrated obesity as associated with a decreased risk of ACM, CSM, and recurrence (HR 0.68, P = 0.04; HR 0.59, P = 0.01; HR 0.59, P = 0.01, respectively), while in stage I-III ccRCC was not (P = 0.21; P = 0.30; P = 0.19, respectively).

CONCLUSION

Our findings refute a broad "obesity paradox" for RCC. Obesity was not associated with improved survival in non-ccRCC and in nonmetastatic ccRCC, while metastatic ccRCC patients with obesity had improved survival outcomes.

Development of a novel score (RENSAFE) to determine probability of acute kidney injury and renal functional decline post surgery: A multicenter analysis

OBJECTIVE

To create and validate 2 models called RENSAFE (RENalSAFEty) to predict postoperative acute kidney injury (AKI) and development of chronic kidney disease (CKD) stage 3b in patients undergoing partial (PN) or radical nephrectomy (RN) for kidney cancer.

METHODS

Primary objective was to develop a predictive model for AKI (reduction >25% of preoperative eGFR) and de novo CKD≥3b (<45 ml/min/1.73m2), through stepwise logistic regression. Secondary outcomes include elucidation of the relationship between AKI and de novo CKD≥3a (<60 ml/min/1.73m2). Accuracy was tested with receiver operator characteristic area under the curve (AUC).

RESULTS

AKI occurred in 452/1,517 patients (29.8%) and CKD≥3b in 116/903 patients (12.8%). Logistic regression demonstrated male sex (OR = 1.3, P = 0.02), ASA score (OR = 1.3, P < 0.01), hypertension (OR = 1.6, P < 0.001), R.E.N.A.L. score (OR = 1.2, P < 0.001), preoperative eGFR<60 (OR = 1.8, P = 0.009), and RN (OR = 10.4, P < 0.0001) as predictors for AKI. Age (OR 1.0, P < 0.001), diabetes mellitus (OR 2.5, P < 0.001), preoperative eGFR <60 (OR 3.6, P < 0.001) and RN (OR 2.2, P < 0.01) were predictors for CKD≥3b. AUC for RENSAFE AKI was 0.80 and 0.76 for CKD≥3b. AKI was predictive for CKD≥3a (OR = 2.2, P < 0.001), but not CKD≥3b (P = 0.1). Using 21% threshold probability for AKI achieved sensitivity: 80.3%, specificity: 61.7% and negative predictive value (NPV): 88.1%. Using 8% cutoff for CKD≥3b achieved sensitivity: 75%, specificity: 65.7%, and NPV: 96%.

CONCLUSION

RENSAFE models utilizing perioperative variables that can predict AKI and CKD may help guide shared decision making. Impact of postsurgical AKI was limited to less severe CKD (eGFR<60 ml/min 71.73m2). Confirmatory studies are requisite.