Letter to the editor: Fatty liver and mortality in populations who are elderly

To the editor, The study by van Kleef et al. showed that the presence of fatty liver disease was not associated with mortality in their cohort. The authors finally concluded that screening for fatty liver disease and/or fibrosis was unlikely to improve outcomes among the people who were elderly.1 We are very interested in this innovative opinion, but there are remaining questions. First, the authors adjusted for several factors in the multivariable‐adjusted analysis. However, some of these factors are closely related to fatty liver, such as individual components of the metabolic syndrome, heart failure, coronary heart disease, and stroke. The relationship between fatty liver and these factors needs to be further explained. Second, among participants with cause‐specific mortality data (344/793), only one died of liver‐related death. Such low liver‐related mortality may be because of the short median follow‐up period of 6.2 years, because another study with a median follow‐up of 14.2 years reported 4338 deaths among 10,568 patients with fatty liver.2 The relative importance of liver‐related deaths may be lower and overshadowed by cardiovascular and cancer‐related deaths in people who are elderly in a short period. In addition, few recorded deaths yield imprecise risk estimates and poor generalizability. Third, the research reported that the epidemiology of NAFLD had sexual dimorphism, and the incidence of liver‐related death was higher in men before the age of 70 but higher in women afterward. The incidence of liver‐related death in women increased from 0.62 to 7.14 per 10,000 person‐years from age 60–69 years to 70–79 years.3 42.7% of the 4093 participants in this study were male, further studies of the relationship between elderly fatty liver and mortality by sex may generate innovative hypotheses. Finally, previous studies have shown that fatty liver significantly increases risks of overall mortality and mortality in a dose‐dependent manner with worsening NAFLD severity.4 Substantial evidence linked fatty liver severity with an increased risk of fatal disease events. Liver biopsy is the gold standard for assessing steatosis and fibrosis. The effect of fatty liver on cause‐specific mortality may differ if invasive biopsy parameters are used to diagnose different steatosis grades.