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©The Author(s) 2016. Published by Baishideng Publishing Group Inc. All rights reserved.
Fatty liver index vs waist circumference for predicting non-alcoholic fatty liver disease
Nima Motamed, Masoudreza Sohrabi, Hossein Ajdarkosh, Gholamreza Hemmasi, Mansooreh Maadi, Fatemeh Sima Sayeedian, Reza Pirzad, Khadijeh Abedi, Sivil Aghapour, Mojtaba Fallahnezhad, Farhad Zamani
Nima Motamed, Department of Social Medicine, Zanjan University of Medical Sciences, Zanjan 45154, Iran
Nima Motamed, Gastrointestinal and Liver Disease Research Center, Iran University of Medical Sciences, Tehran 159347, Iran
Nima Motamed, Masoudreza Sohrabi, Hossein Ajdarkosh, Gholamreza Hemmasi, Mansooreh Maadi, Reza Pirzad, Khadijeh Abedi, Sivil Aghapour, Farhad Zamani, Gastrointestinal and Liver Disease Research Center, Iran University of Medical Sciences, Tehran 159347, Iran
Fatemeh Sima Sayeedian, Department of Endocrinology, Sari University of Medical Sciences, Tehran 159347, Iran
Mojtaba Fallahnezhad, Razi Science Researchers Institute, Karaj 31976, Iran
Author contributions: Motamed N provided the study concept and design, performed data analysis and interpretation, and contributed to the drafting of the manuscript; Sohrabi M performed data acquisition, as well as drafting and revising the manuscript; Ajdarkosh H, Hemmasi G and Sayeedian FS performed critical revision of the manuscript for important intellectual content; Maadi M performed data acquisition, as well as providing administrative, technical, and material support; Fallahnezhad M and Aghapour S provided administrative, technical, and material support; Zamani F performed critical revision of the manuscript, as well as supervising both the study and its manuscript.
Supported by GILDRC, Iran University of Medical Sciences.
Institutional review board statement: This study was reviewed and approved by the Gastrointestinal and Liver Disease Research Center Review Board.
Informed consent statement: All involved persons, or their legal guardian, gave their informed consent prior to study enrollment.
Conflict-of-interest statement: The authors have no conflicts of interest to report.
Data sharing statement: Address to Farhad Zamani or Nima Motamed.
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: Farhad Zamani, MD, Professor, Gastrointestinal and Liver Disease Research Center, Iran University of Medical Sciences, Firoozgar Hospital, Beh Afarin Ave, Valiasr Sq., Tehran 159374, Iran. zamani.f@iums.ac.ir
Telephone: +98-21-88940489 Fax: +98-21-88940489
Received: September 20, 2015
Peer-review started: September 21, 2015
First decision: October 14, 2015
Revised: November 5, 2015
Accepted: December 8, 2015
Article in press: December 8, 2015
Published online: March 14, 2016
AIM: To determine the discriminatory performance of fatty liver index (FLI) for non-alcoholic fatty liver disease (NAFLD).
METHODS: The data of 5052 subjects aged over 18 years were analyzed. FLI was calculated from body mass index, waist circumference (WC), triglyceride, and gamma glutamyl transferase data. Logistic regression analysis was conducted to determine the association between FLI and NAFLD. The discriminatory performance of FLI in the diagnosis of NAFLD was evaluated by receiver operating characteristic analysis. Area under the curves (AUCs) and related confidence intervals were estimated. Optimal cutoff points of FLI in the diagnosis of NAFLD were determined based on the maximum values of Youden’s index.
RESULTS: The mean age of men and women in the study population were 44.8 ± 16.8 and 43.78 ± 15.43, respectively (P = 0.0216). The prevalence of NAFLD was 40.1% in men and 44.2% in women (P < 0.0017). FLI was strongly associated with NAFLD, so that even a one unit increase in FLI increased the chance of developing NAFLD by 5.8% (OR = 1.058, 95%CI: 1.054-1.063, P < 0.0001). Although FLI showed good performance in the diagnosis of NAFLD (AUC = 0.8656 (95%CI: 0.8548-0.8764), there was no significant difference with regards to WC (AUC = 0.8533, 95%CI: 0.8419-0.8646). The performance of FLI was not significantly different between men (AUC = 0.8648, 95%CI: 0.8505-0.8791) and women (AUC = 0.8682, 95%CI: 0.8513-0.8851). The highest performance with regards to age was related to the 18-39 age group (AUC = 0.8930, 95%CI: 0.8766-0.9093). The optimal cutoff points of FLI were 46.9 in men (sensitivity = 0.8242, specificity = 0.7687, Youden’s index = 0.5929) and 53.8 in women (sensitivity = 0.8233, specificity = 0.7655, Youden’s index = 0.5888).
CONCLUSION: Although FLI had acceptable discriminatory power in the diagnosis of NAFLD, WC was a simpler and more accessible index with a similar performance.
Core tip: The present study was carried out to evaluate the discriminatory capability of fatty liver index in the diagnosis of non-alcoholic fatty liver disease (NAFLD) among the general population of northern Iran. Our results showed that the chance of NAFLD occurrence was increased by 5.8% after a one unit increase in fatty liver index (FLI). Although we found that FLI has good discriminatory power, its capability was not superior to that of waist circumference.
