C-reactive Protein/Albumin Ratio and Acute Kidney Injury after Radical Cystectomy among Elderly Patients: A Propensity Score-Matched Analysis

Abstract

Background. The C-reactive protein (CRP)/albumin ratio is a useful index used to represent patient inflammation and nutritional status. Elderly patients are at the highest risk for acute kidney injury (AKI). We clarified the impact of the preoperative CRP/albumin ratio on AKI and evaluated the impact of postoperative AKI on end-stage renal disease (ESRD) among elderly cystectomy patients. Methods. We included elderly $\text{patients}\ge 65\text{years}$ of age who underwent radical cystectomy. Multivariate logistic regression analysis and receiver operating characteristic curve analysis were performed to identify risk factors for AKI. Propensity score-matched analysis and conditional logistic regression analysis were performed to elucidate the impact of the CRP/albumin ratio on AKI. The incidence of ESRD was compared between the non-AKI and AKI groups at 12 months after radical cystectomy. Results. AKI occurred in 110 patients (32.2%). The CRP/albumin ratio and 6% hydroxyethyl starch amount were risk factors for postoperative AKI. The optimal cut-off value for the CRP/albumin ratio predicting AKI was 0.1. After propensity score matching, the AKI incidence in the CRP/albumin $\text{ratio}\ge 0.1$ group was higher than that in the CRP/albumin $\text{ratio}<0.1$ group (46.7% vs. 20.6%, $P<0.001$ ), and a CRP/albumin $\text{ratio}\ge 0.1$ was associated with a higher AKI incidence ( $\text{odds}\text{ratio}=4.111$ , $P<0.001$ ). The ESRD incidence was higher in the AKI group than in the non-AKI group (7.3% vs. 1.2%, $P=0.017$ ). Conclusion. A CRP/albumin $\text{ratio}\ge 0.1$ was associated with an increased incidence of AKI, which was associated with higher ESRD incidence among elderly cystectomy patients.