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 <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"><a:mtext>patients</a:mtext><a:mo>≥</a:mo><a:mn>65</a:mn><a:mtext> </a:mtext><a:mtext>years</a:mtext></a:math> 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 <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"><c:mtext>ratio</c:mtext><c:mo>≥</c:mo><c:mn>0.1</c:mn></c:math> group was higher than that in the CRP/albumin <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" id="M3"><e:mtext>ratio</e:mtext><e:mo>&lt;</e:mo><e:mn>0.1</e:mn></e:math> group (46.7% vs. 20.6%, <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" id="M4"><g:mi>P</g:mi><g:mo>&lt;</g:mo><g:mn>0.001</g:mn></g:math> ), and a CRP/albumin <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" id="M5"><i:mtext>ratio</i:mtext><i:mo>≥</i:mo><i:mn>0.1</i:mn></i:math> was associated with a higher AKI incidence ( <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" id="M6"><k:mtext>odds</k:mtext><k:mtext> </k:mtext><k:mtext>ratio</k:mtext><k:mo>=</k:mo><k:mn>4.111</k:mn></k:math> , <m:math xmlns:m="http://www.w3.org/1998/Math/MathML" id="M7"><m:mi>P</m:mi><m:mo>&lt;</m:mo><m:mn>0.001</m:mn></m:math> ). The ESRD incidence was higher in the AKI group than in the non-AKI group (7.3% vs. 1.2%, <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" id="M8"><o:mi>P</o:mi><o:mo>=</o:mo><o:mn>0.017</o:mn></o:math> ). Conclusion. A CRP/albumin <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" id="M9"><q:mtext>ratio</q:mtext><q:mo>≥</q:mo><q:mn>0.1</q:mn></q:math> was associated with an increased incidence of AKI, which was associated with higher ESRD incidence among elderly cystectomy patients.