Case Control Study
Copyright ©The Author(s) 2022. Published by Baishideng Publishing Group Inc. All rights reserved.
World J Hepatol. Mar 27, 2022; 14(3): 551-558
Published online Mar 27, 2022. doi: 10.4254/wjh.v14.i3.551
Prevalence of hypothyroidism and effect of thyroid hormone replacement therapy in patients with non-alcoholic fatty liver disease: A population-based study
Ashraf Almomani, Asif Ali Hitawala, Prabhat Kumar, Sura Alqaisi, Dana Alshaikh, Motasem Alkhayyat, Imad Asaad
Ashraf Almomani, Prabhat Kumar, Sura Alqaisi, Motasem Alkhayyat, Department ofInternal Medicine, Cleveland Clinic Foundation, Cleveland, OH 44111, United States
Asif Ali Hitawala, Liver Disease Branch, National Institute of Diabetes and Digestive and Kidney Diseases/National Institutes of Health, Bethesda, MD 20892, United States
Dana Alshaikh, Mutah University, Amman 00962, Jordan
Imad Asaad, Department of Digestive Disease and Surgery Institute, Cleveland Clinic Foundation, Cleveland, OH 44195, United States
Author contributions: Almomani A and Kumar P wrote the manuscript; Hitawala AA designed the study; Alkhayyat M performed the statistical analysis; Alqaisi S, Alshaikh D collected the data; Asaad I is the corresponding author.
Institutional review board statement: No Institutional Review Board approval was required for this study since the database is de-identified.
Conflict-of-interest statement: No conflict of interest.
Data sharing statement: No additional data are available.
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: Imad Asaad, MD, Staff Physician, Department of Digestive Disease and Surgery Institute, Cleveland Clinic Foundation, 9500 Euclid Ave, Cleveland, OH 44195, United States. asaadi@ccf.org
Received: August 16, 2021
Peer-review started: August 16, 2021
First decision: November 11, 2021
Revised: November 13, 2021
Accepted: February 24, 2022
Article in press: February 24, 2022
Published online: March 27, 2022
ARTICLE HIGHLIGHTS
Research background

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide, and hypothyroidism has been identified as an independent risk factor. The available data are limited by small sample size and the effect of thyroid hormone replacement therapy is not well studied.

Research motivation

The main topics of this article is to give a focused analysis on the hypothyroidism and to assess whether it is an independent risk factor for the development of NAFLD by filling the small sample size gap in the literature, provide a review of the current medical literature in this field, and -most importantly- to evaluate the role of thyroid hormone replacement therapy in the prevention of the disease.

Research objectives

The objective of this case control study is to assess whether hypothyroidism is an independent risk factor for the development of NAFLD, to review the updated medical literature, and to assess the role of thyroid hormone replacement therapy in the prevention of the disease.

Research methods

We used a validated multicenter database (Explorys Inc.) from pooled outpatient and inpatient records of 26 different healthcare systems, consisting of a total of 360 hospitals in the United States to collect our data. We evaluated a cohort of patients with hypothyroidism and NAFLD. Multivariate analysis was performed to adjust for confounding risk factors including hypertension (HTN), type 2 diabetes mellites (T2DM), dyslipidemia (DLP), obesity and metabolic syndrome. We evaluated a cohort of patients with hypothyroidism and NAFLD. Multivariate analysis was performed to adjust for confounding risk factors including HTN, T2DM, DLP, obesity and metabolic syndrome.

Research results

Among 37648180 in the database who are above the age of 18 years, a total of 2320 patients with NAFLD in the period from 2015 to 2020 were included. NAFLD prevalence was 6.16 per 100000, among which 520 patients (22.4%) had hypothyroidism. Patients with NAFLD were also more likely to have obesity, type 2 diabetes mellitus, dyslipidemia, hypertension, and metabolic syndrome. Males and females were equally affected, but the results were statistically insignificant. Patients in the age group 18-65 years as well as Caucasians seem to be at a higher risk. There was an independent increase in the risk of NAFLD among patients with hypothyroidism, and thyroid hormone replacement was not associated with a decreased risk for developing NAFLD. Prospective studies are needed to better delineate the role of thyroid hormone replacement therapy in these individual.

Research conclusions

There was an independent increase in the risk of NAFLD among patients with hypothyroidism, and thyroid hormone replacement is not associated with a decreased risk for developing NAFLD. Other studies have shown a potential protective effect of thyroid hormone replacement therapy. Based on the conflicting results with the existing literature, further studies are needed to better investigate the relationship between thyroid hormone replacement therapy and NAFLD.

Research perspectives

Future research should focus on assessing the degree of hypothyroidism that leads to NAFLD, and the role of thyroid hormone replacement therapy including the duration of treatment and the end-point goals.