Prospective Study
Copyright ©The Author(s) 2021. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Clin Cases. Jul 6, 2021; 9(19): 5112-5125
Published online Jul 6, 2021. doi: 10.12998/wjcc.v9.i19.5112
Impact of continuous positive airway pressure therapy for nonalcoholic fatty liver disease in patients with obstructive sleep apnea
Haruka Hirono, Kazuhiko Watanabe, Katsuhiko Hasegawa, Masaki Kohno, Shuji Terai, Shogo Ohkoshi
Haruka Hirono, Kazuhiko Watanabe, Katsuhiko Hasegawa, Shogo Ohkoshi, Department of Internal Medicine, The Nippon Dental University School of Life Dentistry at Niigata, Niigata 951-8580, Japan
Masaki Kohno, The Center for Dental Sleep Medicine, The Nippon Dental University Niigata Hospital, Niigata 951-8580, Japan
Shuji Terai, Division of Gastroenterology and Hepatology, Graduate School of Medical and Dental Sciences, Niigata University, Niigata 951-8510, Japan
Author contributions: Hirono H wrote the paper; Ohkoshi S contributed to study conception and design; Hirono H, Watanabe K, Hasegawa K, Kohno M, and Ohkoshi S performed data collection, interpretation and follow-up; Hirono H contributed to data analysis; Ohkoshi S revised the manuscript; Terai S provided research advice; all authors read and approved the final version of the manuscript.
Supported by the Japan Society for the Promotion of Science, No. JP16K09564.
Institutional review board statement: This prospective study was approved by the Ethics Committee of The Nippon Dental University School of Life Dentistry at Niigata, No. ECNG-H-247.
Informed consent statement: Informed consent was obtained from each patient prior to enrollment in this study.
Conflict-of-interest statement: The authors declare no conflicts of interest.
Data sharing statement: No additional data are available.
CONSORT 2010 statement: The authors have read the CONSORT 2010 Statement, and the manuscript was prepared and revised according to the CONSORT 2010 Statement.
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: Haruka Hirono, MD, PhD, Associate Professor, Department of Internal Medicine, The Nippon Dental University School of Life Dentistry at Niigata, 1-8 Hamauracho, Chuo-ku, Niigata 951-8580, Japan. haruka@ngt.ndu.ac.jp
Received: February 25, 2021
Peer-review started: February 25, 2021
First decision: April 18, 2021
Revised: April 28, 2021
Accepted: May 7, 2021
Article in press: May 7, 2021
Published online: July 6, 2021
ARTICLE HIGHLIGHTS
Research background

Several experimental studies have demonstrated that chronic intermittent hypoxia (CIH) from obstructive sleep apnea (OSA) may be relevant to the presence and severity of nonalcoholic fatty liver disease (NAFLD). Continuous positive airway pressure (CPAP) therapy is the first-line therapy for OSA, and good compliance with CPAP therapy leads to adequate reoxygenation.

Research motivation

It has been controversial whether reoxygenation by CPAP therapy improves the liver injury of NAFLD with OSA.

Research objectives

We evaluated the efficacy of reoxygenation by adequate effective CPAP therapy for liver injury in NAFLD with OSA patients.

Research methods

We prospectively enrolled 123 consecutive patients with OSA who met the indications for CPAP. After excluding for their underlying disease or excessive alcohol consumption, 70 OSA patients were finally included in this study. They were classified into following two groups according to the presence of fatty liver evaluated by ultrasonography: A Normal group and an NAFLD group. Liver fibrosis and steatosis were assessed by transient elastography (TE) using FibroScan® (Echosens, Paris, France). Before and after 6 mo of CPAP therapy, serum markers and TE were assessed for OSA patients in the NAFLD group. The mean usage rate of CPAP therapy for 6 mo was arbitrarily calculated in each patient and expressed as “mean compliance index” (m-CI).

Research results

Influences of CPAP therapy on the liver were evaluated in 50 OSA patients from the NAFLD group. In 50 OSA patients with NAFLD, both aspartate aminotransferase (AST) and alanine aminotransferase (ALT) levels were significantly decreased after 6 mo of CPAP therapy. In multivariate regression model adjusted for quantities of body weight (BW) change during 6 mo of CPAP therapy, high m-CI tended to improve ALT level (P = 0.051). All 17 OSA patients with NAFLD, high m-CI and no BMI changes showed significant improvements in AST and ALT levels. Meanwhile, no significant changes in TE data or serum fibrosis markers were seen.

Research conclusions

Some NAFLD patients could be associated with CIH due to OSA independent of BW changes. We propose that all NAFLD patients be analyzed by polysomnography for the diagnosis of OSA if any symptoms related to OSA become apparent.

Research perspectives

This prospective study demonstrated the efficacy of reoxygenation by adequate effective CPAP therapy for liver injury in NAFLD with OSA patients. An randomized controlled trials to investigate the impacts on NAFLD in OSA patients on CPAP therapy for longer than 3 mo is warranted. Progression from NAFLD to nonalcoholic steatohepatitis could be preventable if patients with OSA and NAFLD can be appropriately selected and receive effective CPAP therapy.