Long-term mortality due to infection associated with elevated liver enzymes: a population-based cohort study

We aimed to investigate whether elevated liver enzymes in the adult population were associated with mortality due to infection. As a population-based cohort study, data from the National Health Insurance Service Health Screening Cohort were used. Adult individuals (aged ≥ 40 years) who underwent standardized medical examination between 2002 and 2003 were included, and infectious mortality was defined as mortality due to infection between 2004 and 2015. Aspartate transaminase (AST), alanine aminotransferase (ALT), γ-glutamyl transpeptidase (γ-GTP), AST/ALT ratio, and dynamic AST/ALT ratio (dAAR) were included in multivariable Cox modeling. A total of 512,746 individuals were included in this study. Infectious mortality occurred in 2444 individuals (0.5%). In the multivariable model, moderate and severe elevation in AST was associated with 1.94-fold [hazard ratio (HR):1.94, 95% confidence interval (CI) 1.71–2.19; P < 0.001] and 3.93-fold (HR: 3.93, 95% CI 3.05–5.07; P < 0.001) higher infectious mortality respectively, compared with the normal AST group. Similar results were observed for moderate and severe elevation in ALT and mild, moderate, and severe elevation in γ-GTP. Additionally, a 1-point increase in the AST/ALT ratio and dAAR was associated with higher infection mortality. Elevated liver enzymes (AST, ALT, AST/ALT ratio, γ-GTP, and dAAR) were associated with increased infectious mortality.