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Korean J Transplant 2023; 37(1): 19-28

Published online March 31, 2023

https://doi.org/10.4285/kjt.22.0047

© The Korean Society for Transplantation

Pretransplant C-reactive protein-to-albumin ratio predicts mortality in kidney transplant recipients: a retrospective cohort study

Jae Wan Kwon1 , Yena Jeon2 , Hee-Yeon Jung1 , Ji-Young Choi1 , Sun-Hee Park1 , Chan-Duck Kim1 , Yong-Lim Kim1 , Deokbi Hwang3 , Woo-Sung Yun3 , Hyung-Kee Kim3 , Seung Huh3 , Eun Sang Yoo4 , Dong-Il Won5 , Jang-Hee Cho1 , Jeong-Hoon Lim1

1 Department of Internal Medicine, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
2 Department of Pathology, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
3 Department of Surgery, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
4 Department of Urology, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea
5 Department of Clinical Pathology, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, Daegu, Korea

Correspondence to: Jang-Hee Cho
Division of Nephrology, Department of Internal Medicine, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, 130 Dongdeok-ro, Jung-gu, Daegu 41944, Korea
E-mail: jh-cho@knu.ac.kr

Jeong-Hoon Lim
Division of Nephrology, Department of Internal Medicine, Kyungpook National University Hospital, School of Medicine, Kyungpook National University, 130 Dongdeok-ro, Jung-gu, Daegu 41944, Korea
E-mail: jh-lim@knu.ac.kr

Received: October 12, 2022; Revised: December 30, 2022; Accepted: January 20, 2023

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Background: The C-reactive protein (CRP)-to-albumin ratio (CAR) is a more effective prognostic indicator than CRP or albumin alone in various diseases. This study aimed to evaluate the predictive value of the CAR for mortality in kidney transplant recipients (KTRs).
Methods: A total of 924 patients who underwent their f irst kidney transplantation at Kyungpook National University Hospital during 2006–2020 were enrolled and classified into quartile (Q) groups according to their pretransplant CAR values. A Cox regression analysis was conducted to analyze the hazard ratios (HRs) of mortality.
Results: Fifty-nine patients died during the posttransplant period (mean, 85.2±44.2 months). All-cause mortality (Q1, 3.0%; Q2, 4.8%; Q3, 7.8%; Q4, 10.0%; P for trend <0.001) and infection-related mortality increased linearly with an increase in CAR (P for trend=0.004). The Q3 and Q4 had higher risks of all-cause mortality than Q1 after adjusting for confounding factors (Q3: adjusted HR [aHR] 2.49, 95% confidence interval [CI] 1.04–5.99, P=0.041; Q4: aHR 3.09, 95% CI 1.31–7.27, P=0.010). Q4 was also independently associated with infection-related mortality (aHR 5.83, 95% CI 1.27–26.8, P=0.023). The area under the curve of the CAR for all-cause and infection-related mortality was higher than that of CRP or albumin alone. There was no association between CAR and death-censored graft failure or acute rejection.
Conclusions: A higher pretransplant CAR increases the risk of posttransplant mortality, particularly infection-related, in KTRs. Pretransplant CAR can be an effective and easily accessible predictor of posttransplant mortality.

Keywords: Albumin, C-reactive protein, C-reactive protein-to-albumin ratio, Kidney transplantation, Mortality

HIGHLIGHTS
  • The C-reactive protein-to-albumin ratio (CAR) has been identified as a useful prognostic marker in various fields, but no study has evaluated its role in kidney transplant recipients.

  • This single-center, retrospective cohort study confirmed a significant association between pretransplant CAR and the risk of mortality in kidney transplant recipients.

  • In particular, high pretransplant CAR was associated with an increased risk of infection-related death.

  • No association was found between CAR and death-censored graft failure or the occurrence of acute rejection.