Retrospective Cohort Study
Copyright ©The Author(s) 2020. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. Nov 27, 2020; 12(11): 1004-1019
Published online Nov 27, 2020. doi: 10.4254/wjh.v12.i11.1004
Phase angle and non-alcoholic fatty liver disease before and after bariatric surgery
Joise Teixeira, Cláudio Augusto Marroni, Paula Rosales Zubiaurre, Ana Henz, Lais Faina, Lilian Kethelyn Pinheiro, Claudio Cora Mottin, Sabrina Alves Fernandes
Joise Teixeira, Department of Postgraduate Program in Medicine: Hepatology, Universidade Federal de Ciências da Saúde de Porto Alegre, Porto Alegre 90050170, RS, Brazil
Cláudio Augusto Marroni, Department of Gastroenterology and Hepatology, Universidade Federal de Ciências da Saúde de Porto Alegre (UFCSPA), Porto Alegre 91760470, RS, Brazil
Paula Rosales Zubiaurre, Department of Center of Morbid Obesity, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre 90610000, RS, Brazil
Ana Henz, Lilian Kethelyn Pinheiro, Sabrina Alves Fernandes, Department of Nutrition, Centro Universitário Metodista (IPA), Porto Alegre 90420060, RS, Brazil
Lais Faina, Department of Vascular Surgery, Hospital Federal dos Servidores do Estado do Rio de Janeiro, Rio de Janeiro 20221161, RJ, Brazil
Claudio Cora Mottin, Department of Obesity and Metabolic Syndrome Center, Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS), Porto Alegre 90619-900, RS, Brazil
Author contributions: Teixeira J and Fernandes SA performed the data collection; all the authors wrote the paper and approved the final version.
Institutional review board statement: This project was approved by the Research Ethics Committee of the Pontifícia Universidade Católica do Rio Grande do Sul (PUCRS). No. 2.423.466.
Informed consent statement: Patients who accepted to participate in the study signed the Informed Consent Form.
Conflict-of-interest statement: The authors declare no conflicts of interest for this article.
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: http://creativecommons.org/Licenses/by-nc/4.0/
Corresponding author: Sabrina Alves Fernandes, RN, Research Scientist, Department of Nutrition, Centro Universitário Metodista (IPA), Coronel Joaquim Pedro Salgado, Porto Alegre 90420060, RS, Brazil. sabrina@drasabrinafernandes.com
Received: June 30, 2020
Peer-review started: June 30, 2020
First decision: August 8, 2020
Revised: August 24, 2020
Accepted: October 12, 2020
Article in press: October 12, 2020
Published online: November 27, 2020
ARTICLE HIGHLIGHTS
Research background

Obesity is a complex chronic inflammatory disease characterized by excessive accumulation of body fat. In obese people, a common comorbidity is non-alcoholic fatty liver disease (NAFLD). NAFLD is considered the most common liver disease in Western countries, affecting 90% of morbidly obese patients eligible for bariatric surgery. To evaluate this patients, bioimpedance (BIA) can be a good method for nutritional and prognostic evaluation, using phase angle (PA).

Research motivation

There are not enough studies to evaluate morbid obesity, its body composition (described by the BIA), and associated comorbidities, such as NAFLD. We believe that the body change resulting from bariatric surgery will reflect an improvement in NAFLD and can be measured by PA, since it reflects cellular integrity and functionality by measuring, through an electrical current, the values of resistance and reactance of the membrane of these cells, with skeletal muscle being a conductor of electrical current and the opposite occurring with fat mass.

Research objectives

The aim of this study was to analyze the behavior of PA in the postoperative period of bariatric surgery, correlating it with changes in body composition and improvement of liver disease.

Research methods

This was a retrospective cohort study that analyzed the medical records of 727 patients undergoing bariatric surgery in a referral center of a teaching hospital in the south of Brazil. For convenience, the sample was carried out from July 2015 to July 2017. The data obtained were related to the protocol for routine pre- and postoperative care at the service's outpatient clinic. Quantitative and categorical variables analyses were performed to assess the association between PA, NAFLD, and body composition before and after bariatric surgery.

Research results

We analyzed 727 patients’ medical records, and 379 patients were selected for having all preoperative data. Regarding PA, 169 patients were analyzed, and 33 patients had liver biopsy pre-and postoperatively with NAFLD information. The PA showed a significant reduction in the postoperative period as well as body composition data. Regarding liver disease, all patients presented a reduction in the degrees and stages of liver disease in the postoperative period, and some had no degree of liver disease.

Research conclusions

The PA decreased after bariatric surgery, with a direct correlation with weight loss and changes in body composition, and it did not correlate with the improvement of NAFLD. With the data presented in this study, we suggest that PA may be a marker of the state of body composition linked to the functionality of skeletal muscle mass.

Research perspectives

Performing large scale prospective studies with long-term follow-up are needed to verify if PA increases with more time after bariatric surgery, since the change in the body composition of the operated patient will reflect an improvement in body mass distribution and, consequently, less inflammatory process.