Association between advanced fibrosis in fatty liver disease and overall mortality based on body fat distribution

Studies on association between fatty liver disease and overall mortality have yielded conflicting results. We evaluated the impact of fatty liver disease and advanced fibrosis on overall morality with a focus on body size and abdominal fat distribution measured by computed tomography.

We performed a prospective cohort study including 34 080 subjects (mean age, 51.4 years; 58.6% men) who underwent abdominal ultrasonography and fat computed tomography, from 2007 to 2015. Fatty liver was diagnosed by ultrasonography, and advanced fibrosis was defined as high probability of advanced fibrosis based on three noninvasive methods, aspartate aminotransferase-to-platelet ratio index, non-alcoholic fatty liver disease fibrosis score, and fibrosis-4 score. Body size was categorized by body mass index into obese (≥ 25 kg/m² ) or nonobese (< 25 kg/m² ). Multivariate proportional Cox hazard regression analyses were performed.

The prevalence of fatty liver disease was 37.5%, while the prevalence of advanced fibrosis in fatty liver disease was 1.8%. During a median follow-up of 87 months (interquartile range, 62-110), 296 deaths occurred. Fatty liver disease was not associated with higher overall mortality (multivariate-adjusted hazard ratio [HR] 1.02, 95% confidence interval [CI] 0.77-1.34), while increased subcutaneous adiposity was associated with decreased mortality (HR 0.72, 95% CI 0.60-0.88). Advanced fibrosis resulted in a 3.5-fold increase in overall mortality (adjusted HR 3.52, 95% CI 1.86-6.65), which was more pronounced in the nonobese.

While fatty liver disease did not impact overall mortality, subcutaneous adiposity was associated with reduced overall mortality. Advanced fibrosis was an independent predictor of increase in overall mortality.