SARS-CoV-2 infection in adult liver transplantation recipients: a systematic review of risk factors for mortality and immunosuppression role

OBJECTIVE: Data on mortality, immunosuppression, and vaccination role regarding liver transplant (LT) recipients affected by COVID-19 are still under debate. This study aims to identify risk factors for mortality and the role of immunosuppression in COVID-19 LT recipients.MATERIALS AND METHODS: A systematic review of SARS-CoV-2 infection in LT recipients was performed. The primary outcomes were risk factors for mortality, the role of immunosuppression and vaccination. A meta-analysis was not performed as there was a different metric of the same outcome (mortality) and a lack of a control group in most studies.RESULTS: Overall, 1,343 LT recipients of 1,810 SOT were included, and data on mortality were available for 1,110 liver transplant recipients with SARS-CoV-2 infection. Mortality ranged be-tween 0-37%. Risk factors of mortality were age >60 years, Mofetil (MMF) use, extra-hepatic sol-id tumour, Charlson Comorbidity Index, male sex, dyspnoea at diagnosis, higher baseline se-rum creatinine, congestive heart failure, chronic lung disease, chronic kidney disease, diabetes, BMI >30. Only 51% of 233 LT patients presented a positive response after vaccination, and older age (>65y) and MMF use were associated with lower antibodies. Tacrolimus (TAC) was identified as a protective factor for mortality.CONCLUSIONS: Liver transplant patients present additional risk factors of mortality related to immunosuppression. Immunosuppression role in the progression to severe infection and mortality may correlate with different drugs. Moreover, fully vaccinated patients have a low-er risk of developing severe COVID-19. The present research suggests safely using TAC and reducing MMF use during the COVID-19 pandemic.