Association between ursodeoxycholic acid use and COVID-19 in individuals with chronic liver disease: a nationwide case-control study in South Korea.

Background: Conflicting evidence exists regarding the effects of ursodeoxycholic acid (UDCA) on coronavirus disease 2019 (COVID-19). This study investigates the association between UDCA administration and COVID-19 infection and its related outcomes in individuals with chronic liver disease (CLD).

Methods: A customized COVID-19 research database (n = 3,485,376) was created by integrating data from the National Health Insurance Service (NHIS) and the Korea Disease Control and Prevention Agency's COVID-19 databases. The study focused on patients diagnosed with COVID-19 in 2021, using the NHIS data from 365 days before diagnosis. To create comparable groups with and without UDCA administration before COVID-19, we used propensity score matching. The primary endpoint was the first confirmed positive result for severe acute respiratory syndrome coronavirus-2. In addition, we identified severe COVID-19-related outcomes. Subgroup analysis were conducted based on the dose of UDCA exposure.

Results: Data from 74,074 individuals with CLD was analyzed. The participants' average age was 57.5 years, and 52.1% (19,277) of those in each group were male. Those with prior UDCA exposure had a significantly lower risk of COVID-19 infection (adjusted OR: 0.80, 95% CI [0.76-0.85]) compared to the non-UDCA group. Additionally, the UDCA group had a lower risk of severe COVID-19 outcomes (adjusted OR: 0.67, 95% CI [0.46-0.98]). Subgroup analyses indicated that there was a decrease in COVID-19 infection and its related outcomes with increasing UDCA exposure dose.

Conclusions: Our large observational study highlights the potential use of readily available UDCA as an adjunctive therapy for COVID-19 in individuals with CLD.