Distinct age-dependent phenotypes of abnormal liver function tests derived from national Emergency Department data

Abnormal liver function tests (LFTs) are frequently performed in Emergency Departments (EDs); however, the systematic characterization of age-dependent clinical phenotypes and pathogen associations remains limited.

Here we aimed to identify the distinct clinical presentations and pathogen-specific associations of pediatric and adult ED visits for abnormal LFTs.

This retrospective cohort study analyzed 26,874 ED visits for abnormal LFTs in South Korea's National Emergency Department Information System (2019-2023). Patients were stratified into pediatric (0-18 years) and adult (19-64 years) groups. We characterized the clinical presentations, concurrent diagnoses, temporal correlations with infectious pathogens, and metabolic comorbidity patterns.

The ED visits included 3,152 pediatric (11.7%) and 23,722 adult patients (88.3%). Pediatric presentations demonstrated fever-predominant profiles (47.3%), respiratory symptoms (6.4%), and infectious disease diagnoses (39.8%) as well as temporal correlations with respiratory viruses (rhinovirus, r=0.30; adenovirus, r=0.28; P<0.001). Adult presentations revealed previously unreported population-level temporal associations with enteric pathogens, including astrovirus (r=0.35), sapovirus (r=0.32), enteropathogenic Escherichia coli (r=0.38), and enterotoxigenic Escherichia coli (r=0.36, all P<0.001) coupled with infectious gastroenteritis (20.9%) and upper gastrointestinal disorders, including gastritis (18.3%). Adults demonstrated clustering of the following metabolic comorbidities: dyslipidemia (7.9%), hypertension (7.8%), and diabetes (6.0%). During the coronavirus disease 2019 pandemic, pediatric visits remained stable, whereas adult visits increased following the implementation of social distancing measures (rate ratio, 0.82; P=0.004).

The ED presentation of abnormal LFTs results demonstrated distinct age-dependent phenotypes with divergent temporal pathogen associations. Pediatric cases reflected acute respiratory viral infections, whereas adult presentations showed novel population-level enteric pathogen associations with upper gastrointestinal disorders and clusters of metabolic comorbidities. These findings provide evidence supporting age-stratified diagnostic approaches for EDs.