Liver function tests and mortality in a cohort of life insurance applicants

Since the widespread introduction of the blood test requirement for life insurance, the interpretation of liver function tests (AST, ALT, GGT) has generated intense interest. Elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) have been shown to be associated with primary liver diseases, as well as increased all-cause mortality. Much of this mortality is mediated by increased cardiovascular risk. Gamma-glutmyltransferase (GGT) has been shown to be a marker for metabolic syndrome and diabetes, cardiovascular diseases and mortality, chronic kidney disease, as well as cancer incidence, and liver disease. In this paper we present a mortality study of abnormal liver function test (LFT) results using a direct life insurer's underwriting application data covering approximately 560,000 applications with insurance blood profiles. The results show a consistent progression of increasing risk ratios as the severity of the LFT finding increases. When GGT alone is elevated or when both ALT and AST are elevated, mortality risk is significantly elevated. Similarly, a trend toward higher mortality with progressively higher levels of ALT, AST and GGT is demonstrated. Related liver chemistry results (alkaline phosphatase, bilirubin, albumin), other risk factors, and age are also considered.