In patients with non-alcoholic fatty liver disease, metabolically abnormal individuals are at a higher risk for mortality while metabolically normal individuals are not

Abstract

Background and aim: Non-alcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease and is strongly associated with metabolic syndrome. The aim of this study is to compare the clinical profile and long-term outcome in NAFLD patients with or without metabolic syndrome.

Methods: The initial cohort (N=6709) was identified from National Health and Nutrition Examination Survey-III (NHANES III, 1988-94) data. Laboratory profiles, body measurement examinations, and mortality data were linked to self-reported questionnaires of demographic and health risk information. NAFLD was defined as significant steatosis on hepatic ultrasound after exclusion of other chronic liver diseases (N=1448). NAFLD patients were classified according to presence or absence of metabolic syndrome. Mortality was determined through December 31, 2006. Cox models were used to estimate hazard ratios and 95% confidence intervals for all-cause, cardiovascular and liver-specific mortality differences between two sub-cohorts of NAFLD with and without metabolic syndrome.

Results: NAFLD participants with metabolic syndrome were more likely to be Non-Hispanic white, older, and have higher aminotransferase levels. All-cause mortality (P<.001) and cardiovascular mortality (P<.001) were higher in NAFLD patients with metabolic syndrome. Furthermore, the presence of metabolic syndrome was independently associated with overall mortality, liver-specific mortality, and cardiovascular mortality. Age was an independent predictor of both all-cause and cardiovascular mortality. Elevated liver enzymes and obesity were two other independent predictors of liver-specific mortality. There were no differences in all-cause, liver-related, or cardiovascular mortality between groups of individuals without liver disease and individuals with NAFLD without metabolic syndrome (metabolically-normal).

Conclusions: Diagnosis of NAFLD with metabolic syndrome is an independent predictor of all-cause, liver-specific, and cardiovascular mortality. In contrast, mortality of metabolically-normal NAFLD patients is similar to the cohort without liver disease.