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.