Retrospective Cohort Study
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World J Gastrointest Surg. Feb 27, 2024; 16(2): 331-344
Published online Feb 27, 2024. doi: 10.4240/wjgs.v16.i2.331
Influence of donor age on liver transplantation outcomes: A multivariate analysis and comparative study
Miran Bezjak, Ivan Stresec, Branislav Kocman, Stipislav Jadrijević, Tajana Filipec Kanizaj, Miro Antonijević, Bojana Dalbelo Bašić, Danko Mikulić
Miran Bezjak, Branislav Kocman, Stipislav Jadrijević, Danko Mikulić, Department of Surgery, University Hospital Merkur, Zagreb 10000, Croatia
Ivan Stresec, Bojana Dalbelo Bašić, Department of Electronics, Microelectronics, Computer and Intelligent Systems, Faculty of Electrical Engineering and Computing, Zagreb 10000, Croatia
Tajana Filipec Kanizaj, Department of Gastroenterology, University Hospital Merkur, Zagreb 10000, Croatia
Miro Antonijević, Development of Software, Nanobit Ltd., Zagreb 10000, Croatia
Author contributions: Bezjak M, Stresec I, and Mikulić D designed the study and contributed to data collection, drafting, and revising the manuscript; Kocman B, Jadrijević S, and Filipec Kanizaj T participated in data collection and they critically reviewed the manuscript; Stresec I, Antonijević M, and Dalbelo Bašić B contributed to the data analysis; all authors read and approved the final version of the manuscript.
Supported by the European Regional Development Fund (DATACROSS), No. KK.01.1.1.01.0009.
Institutional review board statement: This study was reviewed and approved by the Ethics Committee of the University Hospital Merkur, Zagreb (No. 03/1-2180).
Informed consent statement: All patients signed a general informed consent agreeing to the treatment and use of their anonymised clinical data.
Conflict-of-interest statement: All authors have nothing to disclose.
Data sharing statement: The statistical code and dataset associated with this research are available from the corresponding author upon request at [mikulicdanko@gmail.com] for researchers who provide a methodologically sound proposal. To gain access, data requestors will need to sign a non-disclosure agreement (NDA). All data have been anonymized, and the risk of identification is minimized. We may balance the potential benefits and risks for each request and then provide the data that could be shared.
STROBE statement: The authors have read the STROBE Statement—checklist of items, and the manuscript was prepared and revised according to the STROBE Statement—checklist of items.
Open-Access: This article is an open-access article that was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution NonCommercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: https://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Danko Mikulić, FEBS, MD, PhD, Surgeon, Department of Surgery, University Hospital Merkur, Department of Surgery, University Hospital Merkur, 10000 Zagreb, Croatia. mikulicdanko@gmail.com
Received: October 9, 2023
Peer-review started: October 9, 2023
First decision: December 8, 2023
Revised: December 18, 2023
Accepted: January 29, 2024
Article in press: January 29, 2024
Published online: February 27, 2024
Processing time: 138 Days and 21.3 Hours
Abstract
BACKGROUND

The growing disparity between the rising demand for liver transplantation (LT) and the limited availability of donor organs has prompted a greater reliance on older liver grafts. Traditionally, utilizing livers from elderly donors has been associated with outcomes inferior to those achieved with grafts from younger donors. By accounting for additional risk factors, we hypothesize that the utilization of older liver grafts has a relatively minor impact on both patient survival and graft viability.

AIM

To evaluate the impact of donor age on LT outcomes using multivariate analysis and comparing young and elderly donor groups.

METHODS

In the period from April 2013 to December 2018, 656 adult liver transplants were performed at the University Hospital Merkur. Several multivariate Cox proportional hazards models were developed to independently assess the significance of donor age. Donor age was treated as a continuous variable. The approach involved univariate and multivariate analysis, including variable selection and assessment of interactions and transformations. Additionally, to exemplify the similarity of using young and old donor liver grafts, the group of 87 recipients of elderly donor liver grafts (≥ 75 years) was compared to a group of 124 recipients of young liver grafts (≤ 45 years) from the dataset. Survival rates of the two groups were estimated using the Kaplan-Meier method and the log-rank test was used to test the differences between groups.

RESULTS

Using multivariate Cox analysis, we found no statistical significance in the role of donor age within the constructed models. Even when retained during the entire model development, the donor age's impact on survival remained insignificant and transformations and interactions yielded no substantial effects on survival. Consistent insignificance and low coefficient values suggest that donor age does not impact patient survival in our dataset. Notably, there was no statistical evidence that the five developed models did not adhere to the proportional hazards assumption. When comparing donor age groups, transplantation using elderly grafts showed similar early graft function, similar graft (P = 0.92), and patient survival rates (P = 0.86), and no significant difference in the incidence of postoperative complications.

CONCLUSION

Our center's experience indicates that donor age does not play a significant role in patient survival, with elderly livers performing comparably to younger grafts when accounting for other risk factors.

Keywords: Liver transplantation; Elderly donors; Survival analysis; Postoperative complications; Cox proportional hazard models

Core Tip: Liver transplantation (LT) using elderly donor livers is traditionally expected to yield inferior results compared to transplantation using young donor grafts. We assessed the impact of donor age on LT outcomes through multivariate analysis and by comparing young and elderly donor groups. Results from our center show that donor age does not significantly affect patient survival. When adjusting for additional risk factors, elderly livers perform similarly to their younger counterparts. These findings challenge the conventional belief that older donor organs result in inferior outcomes, providing valuable insights for expanding the donor pool for liver transplants.