Abnormal Liver Tests Evaluated for Geriatric Mortality Risk

Abnormal levels in the blood of aspartate transaminase (AST), alkaline phosphatase (ALP) and bilirubin are associated with increased death rates in the elderly.

For people over the age of 75, approximately 17% are likely to have at least one abnormal liver test and those that have two or more are twice as likely to die from cancer and 17 times more likely to die from liver disease.

Scientists at the University of Nottingham (Nottingham, UK) carried out 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 AST, 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. The cohorts were followed for seven years.

Overall, 16.1% of participants with one or more valid measurement had at least one abnormal liver test. The most common abnormal liver test within this population was ALP with 9.2% of participants having a result above the upper limit of normal. Only 5.4% of people had an abnormal bilirubin test, whereas an even smaller proportion had an abnormal AST result. The majority of subjects with an abnormal measurement had a test result less than or equal to twice the upper limit of normal: 86.2% for AST, 90.0% for ALP, and 93.8% for bilirubin. Abnormal liver tests are common in elderly people, but were only associated with a modest increase in deaths from all causes.

Patients with elevated AST measurements tended to be younger and there was an association with alcohol consumption of more than seven units in the previous week. Patients with elevated ALP tended to be older and report lower alcohol consumption. Abnormal AST was associated with a sevenfold increased risk of death from liver disease and a 56% increase in cancer risk, while abnormal ALP was associated with nearly a six-fold increased risk of death from liver disease. Patients who had two or more elevated liver tests faced a 54% increased risk of all-cause mortality and the risk of dying from cancer doubled. They were 17 times more likely to die from liver disease than patients with no abnormal liver tests were.

Kate Fleming, PhD, the senior author of the study, said, "There is currently no evidence that a single abnormal and isolated measurement of AST, ALP or bilirubin leads to an overwhelming increase in death rates. Given that, the current clinical practice of only referring and actively investigating patients with multiple or persistent abnormalities should be continued. Older people represent an increasingly large group of healthcare users in the UK and we hope that this research will provide useful information in an area that has previously suffered from lack of research.” The study was published in August 2011 in the journal Alimentary Pharmacology and Therapeutics.

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