Tuberculosis infection via the emergency department among inpatients in South Korea: a propensity score matched analysis of the National Inpatient Sample

BACKGROUND: Emergency departments (EDs) carry a high risk of infectious disease transmission and have also been implicated in tuberculosis (TB) outbreaks. AIM: To determine if patients who visit EDs have an increased risk of TB infection. Using South Korean inpatient sample data (2012), the risk of TB occurrence during 90 days after hospitalization for patients admitted via EDs was compared with that for patients admitted via outpatient clinics. METHODS: The data of the 2012 Health Insurance Review and Assessment Service – National Inpatient Sample were used. TB diagnosis was based on International Classification of Diseases Version 10 [all TB (A15–A19), pulmonary TB (A15-A16) and extrapulmonary TB (A17–A18)]. FINDINGS: After propensity score matching using the demographic and clinical characteristics of the patients, 191,997 patients (64,017 patients admitted via EDs and 127,908 patients admitted via outpatient clinics) were included in this study. There was no significant difference in baseline patient characteristics between the two groups. The percentage of patients with TB admitted via EDs was higher than that of patients admitted via outpatient clinics. The likelihood of active TB occurrence was 30% higher for all TB [hazard ratio (HR) 1.30; 95% confidence interval (CI) 1.12–1.52] and pulmonary TB (HR 1.30; 95% CI 1.10–1.53) in patients admitted via EDs compared with patients admitted via outpatient clinics; this difference was significant. However, no difference in the occurrence of extrapulmonary TB was observed between the two groups. CONCLUSIONS: The likelihood of TB infection was greater in patients admitted via EDs than in patients admitted via outpatient clinics.