Health outcomes following liver function testing in primary care: a retrospective cohort study

Objective. The objective is to follow-up a cohort of liver function tested patients to determine their outcome. Methods. This population-based retrospective cohort study was conducted in Tayside, Scotland, from 1989 to 2003. Subjects were patients with no clinically obvious liver disease at initial liver function testing in primary care. Main outcomes were diagnosed liver disease and mortality. Record linkage of databases ascertained risk factors and outcomes. Measures of performance were calculated and Weibull regression analysis from initial LFT date was performed on all outcomes by level of abnormality. Results. In total, 95 977 patients had 364 194 incident initial LFTs, with median follow-up 3.7 years. A total of 21.7% had at least one abnormal LFT and 1108 (1.15%) developed liver disease. Elevated transaminase was strongly associated with diagnosed liver disease, hazard ratio (HR) = 4.23 (95% confidence interval 3.55, 5.04) for mild levels and HR = 12.67 (95% CI 9.74, 16.47) for severe levels versus normal. For gamma-glutamyl transferase, these hazards were 2.54 (95% CI 2.17, 2.96) and 13.44 (95% CI 10.71, 16.87), respectively. Low albumin was strongly associated with all-cause mortality, HR = 2.65 (95% CI 2.47, 2.85) for mild levels and HR = 4.99 (95% CI 4.26, 5.84) for severe levels. Sensitivity for predicting events over 5 years was low and specificity high. Conclusions. All LFTs were predictive markers for liver disease as well as general ill health, although sensitivity was poor. Most patients with abnormal LFTs had no later formal diagnosis of liver disease within the study period. The time taken to develop liver disease in these patients provides opportunity to intervene.