Original Article
Copyright ©2013 Baishideng Publishing Group Co., Limited. All rights reserved.
World J Gastroenterol. Feb 28, 2013; 19(8): 1219-1229
Published online Feb 28, 2013. doi: 10.3748/wjg.v19.i8.1219
NAFLD fibrosis score: A prognostic predictor for mortality and liver complications among NAFLD patients
Sombat Treeprasertsuk, Einar Björnsson, Felicity Enders, Sompongse Suwanwalaikorn, Keith D Lindor
Sombat Treeprasertsuk, Sompongse Suwanwalaikorn, Department of Medicine, Faculty of Medicine, Chulalongkorn University, Bangkok 10330, Thailand
Einar Björnsson, Department of Internal Medicine, Section of Gastroenterology and Hepatology, the National University Hospital of Iceland, IS121 Reykjavik, Iceland
Felicity Enders, Biostatistics and Health Sciences Research, Mayo Clinic, Rochester, MN 55902, United States
Keith D Lindor, Health Solutions, Arizona State University, Tempe, AZ 85004, United States
Author contributions: Treeprasertsuk S designed and performed the experiments, analysed data, wrote the manuscript; Björnsson E critially revised the manuscript; Enders F performed statistical analysis and interpreted data; Suwanwalaikorn S edited the manuscript; Lindor KD suggested the study concept and were also involved in editing the manuscript.
Correspondence to: Sombat Treeprasertsuk, MD, Associate Professor, Department of Medicine, Faculty of Medicine, Chulalongkorn University, 4 Rama Road, Pathumwan District, Bangkok 10330, Thailand. battan5410@gmail.com
Telephone: +66-2-2564265 Fax: +66-2-2527839
Received: September 26, 2012
Revised: November 1, 2012
Accepted: November 21, 2012
Published online: February 28, 2013

AIM: To study whether the severity of liver fibrosis estimated by the nonalcoholic fatty liver disease (NAFLD) fibrosis score can predict all-cause mortality, cardiac complications, and/or liver complications of patients with NAFLD over long-term follow-up.

METHODS: A cohort of well-characterized patients with NAFLD diagnosed during the period of 1980-2000 was identified through the Rochester Epidemiology Project. The NAFLD fibrosis score (NFS) was used to separate NAFLD patients with and without advanced liver fibrosis. We used the NFS score to classify the probability of fibrosis as < -1.5 for low probability, > -1.5 to < 0.67 for intermediate probability, and > 0.67 for high probability. Primary endpoints included all-cause death and cardiovascular- and/or liver-related mortality. From the 479 patients with NAFLD assessed, 302 patients (63%) greater than 18 years old were included. All patients were followed, and medical charts were reviewed until August 31, 2009 or the date when the first primary endpoint occurred. By using a standardized case record form, we recorded a detailed history and physical examination and the use of statins and metformin during the follow-up period.

RESULTS: A total of 302/479 (63%) NAFLD patients (mean age: 47 ± 13 year) were included with a follow-up period of 12.0 ± 3.9 year. A low probability of advanced fibrosis (NFS < -1.5 at baseline) was found in 181 patients (60%), while an intermediate or high probability of advanced fibrosis (NSF > -1.5) was found in 121 patients (40%). At the end of the follow-up period, 55 patients (18%) developed primary endpoints. A total of 39 patients (13%) died during the follow-up. The leading causes of death were non-hepatic malignancy (n = 13/39; 33.3%), coronary heart disease (CHD) (n = 8/39; 20.5%), and liver-related mortality (n = 5/39; 12.8%). Thirty patients had new-onset CHD, whereas 8 of 30 patients (27%) died from CHD-related causes during the follow-up. In a multivariate analysis, a higher NFS at baseline and the presence of new-onset CHD were significantly predictive of death (OR = 2.6 and 9.2, respectively; P < 0.0001). Our study showed a significant, graded relationship between the NFS, as classified into 3 subgroups (low, intermediate and high probability of liver fibrosis), and the occurrence of primary endpoints. The use of metformin or simvastatin for at least 3 mo during the follow-up was associated with fewer deaths in patients with NAFLD (OR = 0.2 and 0.03, respectively; P < 0.05). Additionally, the rate of annual NFS change in patients with an intermediate or high probability of advanced liver fibrosis was significantly lower than those patients with a low probability of advanced liver fibrosis (0.06 vs 0.09, P = 0.004). The annual NFS change in patients who died was significantly higher than those in patients who survived (0.14 vs 0.07, P = 0.03). At the end of the follow-up, we classified the patients into 3 subgroups according to the progression pattern of liver fibrosis by comparing the NFS at baseline to the NFS at the end of the follow-up period. Most patients were in the stable-fibrosis (60%) and progressive-fibrosis (37%) groups, whereas only 3% were in the regressive fibrosis.

CONCLUSION: A higher NAFLD fibrosis score at baseline and a new onset of CHD were significantly predictive of death in patients with NAFLD.

Keywords: Nonalcoholic fatty liver disease fibrosis score, Prognostic predictor, Mortality, Liver complications