Impact of ursodeoxycholic acid therapy in autoimmune liver disease patients with COVID-19 and its clinical prognosis

•Scientific question: Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which presents with multiple clinical features. The relation between SARS-CoV-2 infection and autoimmune liver disease (AILD) remains unclear.•Evidence before this study: Patients with stable chronic liver diseases such as autoimmune hepatitis (AIH), primary biliary cholangitis (PBC), or PSC are more susceptible to SARS-CoV-2 infection. Researchers from the University of Cambridge published a novel finding in Nature demonstrating that ursodeoxycholic acid (UDCA) could inhibit ACE2 receptor expression, thus reducing SARS-CoV-2 infection.•New findings: UDCA is associated with low SARS-CoV-2 incidence in AILD patients, while immunosuppressant increases its incidence instead. Patients receiving UDCA treatment have a longer recovery time after being infected.•Significance of the study: Our study on AILD patients with SARS-CoV-2 infection suggests that the utilization of UDCA might reduce the occurrence of SARS-CoV-2 infection in AILD patients, thereby providing a foundation for preventive and therapeutic strategies involving concurrent use of UDCA treatment. To explore the impact of ursodeoxycholic acid (UDCA) on severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and clinical outcomes in patients with autoimmune liver disease (AILD). Patients diagnosed with AILD were enrolled and divided into a UDCA group and a non-UDCA group based on whether they received UDCA treatment. Relevant data were collected regarding AILD diagnosis, treatment, biochemical indicators, and imaging examination. The incidence of SARS-CoV-2 infection and the prognosis of AILD patients were observed. A total of 1,138 patients completed follow-up. The usage rate of hormone (P = 0.003) and immunosuppressant (P = 0.001) used for treating AILD in the non-UDCA group was markedly lower than in the UDCA group. The UDCA usage rate was markedly lower in SARS-CoV-2 infected patients than in uninfected patients (P = 0.003). The rate of SARS-CoV-2 infection in the non-UDCA group was significantly higher than in the UDCA group (P = 0.018). Logistic regression analysis showed that UDCA use (P = 0.003) was correlated to a lower incidence of SARS-CoV-2, while immunosuppressant use (P = 0.017) increased the incidence. Recovery time from SARS-CoV-2 infection was markedly longer for those receiving UDCA treatment than those in the non-UD