Nomograms to Appraise The Risk of Chronic Kidney Disease After Radical Cystectomy: Shifting The Focus to Prevention.

ABSTRACT

INTRODUCTION: Our objectives were to analyse the incidence of changes in renal function after radical cystectomy (RC) and determine the factors responsible for those changes, as a basis for rethinking strategies to ensure early detection and development of a risk-adapted approach. PATIENTS AND METHODS: A single-centre retrospective study included 316 patients who underwent RC between 2010 and 2019. A competing risk Cox model, whereby death from any cause was treated as a censoring event, was used to establish nomograms to analyze the prognostic factors for CKD at 2 and 5 years. The nomograms were validated based on discrimination using the C-index, calibration plots and analysis of net benefit from decision curves. RESULTS: During a median follow-up of 48.73 months (0.13-156.67), 138 patients (43.7%) developed CKD. The probability of CKD development at 2 and 5 years was 41.3% (95% CI, 35.8-47.2) and 48.5% (95% CI, 42.8-54.6), respectively. Hypertension (HR 1.69, 95% CI, 1.23-2.34), prior hydronephrosis (HR 1.62, 95% CI, 1.17-2.25), acute kidney injury (AKI) during the immediate postoperative period (HR 1.88, 95% CI, 1.35-2.61) and readmission due to urinary tract infection (HR 1.41, 95% CI, 1.01-1.96) were predictors of 2-year CKD. Hydronephrosis at follow-up computed tomography (HR 2.21, 95% CI, 1.60-3.07), prior hydronephrosis (HR 1.54, 95% CI, 1.09-2.15), AKI during the immediate postoperative period (HR 1.77, 95% CI, 1.27-2.46) and hypertension (HR 1.60, 95% CI, 1.16-2.21) were predictors for 5-year CKD. Prior eGFR ≥ 90 mL/min/1.73 m2 was a protective factor (HR 0.50, 95% CI, 0.32-0.80 and HR 0.48, 95% CI, 0.30-0.78 for 2- and 5-year CKD, respectively). The resulting nomograms were based on these prognostic factors. CONCLUSION: Almost half of the patients had developed CKD at 5 years. Thus, it is crucial to identify patients at risk of developing CKD in order to initiate renal function-sparing measures and tailor follow-up protocols. The proposed nomograms effectively predicted CKD in these patients.