Abnormal liver tests in people aged 75 and above: prevalence and association with mortality

Background Despite their common use the occurrence and consequences of abnormal liver tests remain unclear. Aims To estimate the prevalence and mortality associated with abnormal liver tests in people aged 75 years and above. Methods A cohort study on 13 276 people aged 75 years and above, registered with general practices, with a valid measurement of one or more liver test, calculating the prevalence of abnormal aspartate transaminase (AST), alkaline phosphatase (ALP) or bilirubin. Hazard ratios (HRs) were calculated for all-cause and cause-specific mortality comparing elderly patients with abnormal liver tests to elderly patients with normal liver tests. Results At least one abnormal liver test was found in 2175 subjects (16.1%, 95% CI [15.4%, 16.7%]). The prevalence of a single abnormal liver test was 3.3% (95% CI [3.0%, 3.7%]) for AST, 9.2% (95% CI [8.8%, 9.7%]) for ALP and 5.4% (95% CI [5.1%, 5.9%]) for bilirubin. Abnormal AST, ALP and bilirubin were associated with increased risks of all-cause mortality; adjusted HRs, 1.27(95% CI [1.09, 1.47]), 1.47(95% CI [1.35, 1.61]) and 1.15(95% CI [1.02, 1.30]), respectively. Abnormal AST and ALP were associated with sevenfold and sixfold increased risk of death from liver disease, respectively. Two or more abnormal liver tests were associated with 2-fold and 17-fold increased risk of death from cancer and liver disease, respectively. Of the causes examined, absolute mortality rates were highest for cardiovascular disease in subjects with and without abnormal liver tests. Conclusions Abnormal liver tests occur commonly in elderly people and are associated with a modest increase in all-cause mortality. There was a strong association with liver disease; however, the majority of deaths were not due to this cause.