Abstract
BACKGROUND AND AIMS: Previous studies have examined the effects of metabolic syndrome (MetS) presence rather than the severity on mortality risk in nonalcoholic fatty liver disease (NAFLD). We used the MetS severity score, a validated gender- and race-specific measure, to assess the relationship between MetS severity and mortality risk in NAFLD. METHODS: The study included 10,638 adults aged between 20 and 74 years who participated in the Third National Health and Nutrition Examination Survey. NAFLD was defined as mild, moderate, or severe hepatic steatosis on ultrasound without excessive alcohol intake and other liver diseases. Adjusted Cox proportional models were used to test the association between the MetS severity score and mortality risk related to all-cause, heart disease, diabetes, and hypertension. RESULTS: The median MetS severity score was significantly higher in NAFLD (0.49 [69th] vs -0.23 [41st]). An increase in the MetS severity corresponded to a linear rise in biomarkers for cardiovascular disease, insulin resistance, lipid abnormalities, and liver and kidney problems. The MetS severity score was a significant predictor for all-cause and cause-specific adjusted mortalities. A quartile increase in MetS severity score was associated with higher mortality risks from all-causes adjusted hazard ratio (aHR) 1.36 (95% confidence interval [CI]: 1.17-1.57), heart disease aHR 1.70 (95% CI: 1.17-2.47), diabetes aHR 3.64 (95% CI: 2.27-5.83), and hypertension aHR 1.87 (95% CI: 1.14-3.04). A higher MetS severity score was also associated with nonlinear increased risks of mortality in all adjusted models. CONCLUSION: The MetS severity score is a clinically accessible tool that can be used to identify and monitor NAFLD patients at the highest risk of mortality.