Retrospective Cohort Study
Copyright ©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Transplant. Jun 24, 2016; 6(2): 356-369
Published online Jun 24, 2016. doi: 10.5500/wjt.v6.i2.356
Impact of body mass index on outcomes of 48281 patients undergoing first time cadaveric liver transplantation
Subhashini Ayloo, Scott Hurton, Matthew Cwinn, Michele Molinari
Subhashini Ayloo, Scott Hurton, Matthew Cwinn, Michele Molinari, Department of Surgery, Victoria General Hospital, Dalhousie University, Halifax, Nova Scotia B3H 2Y9, Canada
Michele Molinari, Department of Public Health and Epidemiology, Dalhousie University, Halifax, Nova Scotia B3H 2Y9, Canada
Author contributions: Ayloo S and Molinari M designed the research, analyzed the data, created tables and graphics; Hurton S and Cwinn M reviewed the literature, revised the manuscript.
Institutional review board statement: This study was performed using data extracted from UNOS Standard Transplant Analysis and Research (STAR) Files collected in the United States. Local Institutional Review Board approval was not required.
Informed consent statement: Since this study was performed using data extracted from UNOS Standard Transplant Analysis and Research (STAR) Files, acquisition of patients consent statements was neither feasible nor required.
Conflict-of-interest statement: All the Authors have no conflict of interest related to the manuscript.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (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: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Dr. Michele Molinari, Department of Surgery, Victoria General Hospital, Dalhousie University, 1276 South Park Street, Office, 6-302 Centennial Building, Halifax, Nova Scotia B3H 2Y9, Canada. michele.molinari@nshealth.ca
Telephone: +1-902-4737624 Fax: +1-902-4737639
Received: October 25, 2015
Peer-review started: October 27, 2015
First decision: December 28, 2015
Revised: January 6, 2016
Accepted: March 9, 2016
Article in press: March 14, 2016
Published online: June 24, 2016
Processing time: 241 Days and 17.5 Hours
Abstract

AIM: To investigate possible disparities in perioperative morbidity and mortality among different body mass index (BMI) groups and to simulate the impact that these differences might have had on the cohort of patients undergoing cadaveric liver transplantation (LT).

METHODS: All adult recipients undergoing first time LT for benign conditions and receiving a whole graft from brain-dead donors were selected from the united network of organ sharing registry. From January 1994 to June 2013, 48281 patients satisfied the inclusion criteria and were stratified by their BMI. The hypothesis that abnormal BMIs were independent predictors of inferior outcomes was tested with univariate and multivariate regression analyses.

RESULTS: In comparison to normal weight recipients, underweight and morbidly obese recipients had increased 90-d mortality (adjusted OR = 1.737; 95%CI: 1.185-2.548, P = 0.005) (adjusted OR = 1.956; 95%CI: 1.473-2.597, P = 0.000) respectively and inferior patients’ survivals (adjusted HR = 1.265; 95%CI: 1.096-1.461, P = 0.000) (adjusted HR = 1.157; 95%CI: 1.031-1.299, P = 0.013) respectively. Overall, patients’ 5-year survival were 73.9% for normal-weight, 71.1% for underweight, 74.0% for overweight, 74.4% for class I obese, 75.0% for class II obese and 71.5% for class III obese recipients. Analysis of hypothetical exclusion of underweight and morbidly obese patients from the pool of potential LT candidates would have improved the overall survival of the entire cohort by 2.7% (95%CI: 2.5%-3.6%).

CONCLUSION: Selected morbidly obese patients undergoing LT for benign conditions had 5-year survival rates clinically comparable to normal weight recipients. Impact analysis showed that exclusion of high-risk recipients (underweight and morbid obese patients) would not significantly improve the overall survival of the entire cohort of patients requiring LT.

Keywords: Obesity; Impact analysis; Survival; Liver transplantation; Body mass index

Core tip: Obesity has become a prevalent condition in many part of the world. Yet, evaluation of its impact on patients requiring liver transplantation is limited. Analysis of united network of organ sharing data of 48281 patients undergoing first time cadaveric liver transplantation has shown that, 5-year survival rates for selected underweight and morbidly obese patients were clinically comparable to normal weight recipients as 5-year survival for class III obese recipients was 71.5% vs 73.9% for normal weight patients. Impact analysis showed that exclusion of morbidly obese and underweight recipients would not significantly improve the overall survival of the entire cohort of patients undergoing liver transplant.