Despite renal function recovery after NSS has been primarily associated with parenchymal mass preservation and ischemia, frailty status may also contribute to an increased risk of worse functional outcomes. Thus, we aimed at investigating the role of frailty status on long-term renal function in patients undergoing NSS.
Within a prospective maintained database, we identified 1,584 patients treated with NSS for cT1-2N0M0 renal mass at a single tertiary centre . The Modified Frailty Index was adopted to identify frail patients. Estimated glomerular filtration rate (eGFR) was calculated using CKD-EPI formula. Acute kidney injury (AKI) was defined according to the RIFLE criteria. Multivariable logistic regression analyses assessed the impact of frailty on the risk of postoperative AKI, after accounting for age, preoperative eGFR, blood loss and tumor characteristics. Multivariable Poisson regression analyses estimated the risk of eGFR decrease and a local polynomial smoother weighted function was used to graphically explore eGFR over time.
Overall, 1,584 patients were treated with NSS for cT1-cT2 N0M0 renal mass. Of these, 273 (17%) were frail. Frail patients were older (69 vs. 60 years; p<0.001) and more frequently male (73 vs. 67%; p=0.03). Median preoperative eGFR was lower in frail (69 vs. 85 mL/min) vs. non-frail patients. After adjusting for patient and tumor characteristics, frailty status predicted higher risk of postoperative AKI (OR 1.91, 95%CI 1.2-3.5; p=0.01). Median functional follow-up was 5 years. At multivariable analyses, frailty status resulted an independent predictor of greater eGFR decrease at last follow-up (p=0.01). While an improvement on eGFR recovery was shown in non-frail patients, a greater and continuous eGFR decrease over time was demonstrated in frails (Figure 1).
Frail patients are at higher risk of developing AKI after surgery. Moreover, while an eGFR improvement has been shown in non-frail patients, an opposite effect has been observed in frail patients. In consequence, preoperative assessment of frailty in patients undergoing NSS aimed at identifying patients who may benefit from a multidisciplinary approach appears warranted.