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World J Transplant. Mar 24, 2016; 6(1): 135-143
Published online Mar 24, 2016. doi: 10.5500/wjt.v6.i1.135
Kidney transplantation in obese patients
Minh-Ha Tran, Clarence E Foster, Kamyar Kalantar-Zadeh, Hirohito Ichii
Minh-Ha Tran, Division of Transfusion Medicine and Apheresis, Department of Pathology and Laboratory Medicine, University of California, Irvine, School of Medicine, Irvine, CA 92697, United States
Clarence E Foster, Hirohito Ichii, Division of Transplantation, Department of Surgery, University of California, Irvine, School of Medicine, Irvine, CA 92697, United States
Kamyar Kalantar-Zadeh, Division of Nephrology, Department of Medicine, University of California, Irvine, School of Medicine, Irvine, CA 92697, United States
Author contributions: All authors equally contributed to this paper with conception and design of the study, literature review and analysis, drafting and critical revision and editing, and final approval of the final version.
Supported by (In part) grants from: NIH-NCRR UL1 TR000153, KL2 TR000147; and the Juvenile Diabetes Research Foundation International 17-2011-609.
Conflict-of-interest statement: No potential conflict of interest.
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: Hirohito Ichii, MD, PhD, Division of Transplantation, Department of Surgery, University of California, Irvine, School of Medicine, 333 City Boulevard West Suite 1205, Orange, Irvine, CA 92697, United States. hichii@uci.edu
Telephone: +1-714-4568698 Fax: +1-714-4568796
Received: July 29, 2015
Peer-review started: August 5, 2015
First decision: October 13, 2015
Revised: October 25, 2015
Accepted: December 17, 2015
Article in press: December 18, 2015
Published online: March 24, 2016
Abstract

The World Health Organization estimated that in 2014, over 600 million people met criteria for obesity. In 2011, over 30% of individuals undergoing kidney transplant had a body mass index (BMI) 35 kg/m2 or greater. A number of recent studies have confirmed the relationship between overweight/obesity and important comorbidities in kidney transplant patients. As with non-transplant surgeries, the rate of wound and soft tissue complications are increased following transplant as is the incidence of delayed graft function. These two issues appear to contribute to longer length of stay compared to normal BMI. New onset diabetes after transplant and cardiac outcomes also appear to be increased in the obese population. The impact of obesity on patient survival after kidney transplantation remains controversial, but appears to mirror the impact of extremes of BMI in non-transplant populations. Early experience with (open and laparoscopic) Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy support excellent weight loss (in the range of 50%-60% excess weight lost at 1 year), but experts have recommended the need for further studies. Long term nutrient deficiencies remain a concern but in general, these procedures do not appear to adversely impact absorption of immunosuppressive medications. In this study, we review the literature to arrive at a better understanding of the risks related to renal transplantation among individuals with obesity.

Keywords: Body mass index, Overweight, Obese, Kidney transplant, Transplant complications, Transplant outcomes, Patient survival, Graft survival

Core tip: Extremes of body mass index (BMI) appear to impact survival in kidney transplant recipients, but this effect appears to parallel that seen in the general population. Skin and soft-tissue complications, particularly wound infections and lymphocele formation, are higher among obese patients. In addition, the rate of delayed graft function is also higher, and contributes to longer length of stay following transplant in this population. New onset diabetes after transplant also appears to be influenced both by BMI at time of transplant as well as increasing BMI following transplant. Measures of central adiposity, such as waist-to-hip ratio, may enhance risk assessment. Bariatric surgery appears promising to aid in reducing excess weight both pre- and post-transplant, but further studies are needed. Obesity should not constitute an absolute contraindication to transplantation but individualized risk assessment is necessary.