Study population
Consecutive adult (aged >18 years at the time of SARS-CoV-2 infection) liver transplant recipients with concomitant confirmed SARS-CoV-2 infection were included in the study. The definition of confirmed SARS-CoV-2 infection was made according to the WHO guidelines and based on the presence of a laboratory assay proving SARS-CoV-2 infection, irrespective of clinical signs and symptoms of the disease.20 Nucleic acid amplification test (NAAT) positive for SARS-CoV-2 in nasopharyngeal swab, sputum samples and bronchoalveolar lavage (BAL) was considered diagnostic. Typical radiological findings included bilateral, peripheral, consolidation and/or ground glass opacities, detected by using chest X-ray or thorax-CT scan.21
Patients were enrolled in the study at the time of diagnosis of COVID-19 and were followed up until death or 10 May 2020.
Baseline information regarding indication to liver transplantation, underlying liver disease and comorbidities, as well as anthropometric data were collected. At the time of COVID-19 diagnosis, clinical features and laboratory parameters were recorded. All laboratory and imaging investigations were performed as part of standard care of patients. Information on management of baseline immunosuppression, namely, its reduction or discontinuation, as well as specific pharmacological therapies and ventilation support, were obtained.
Patients were classified according to the severity of COVID-19 disease in outpatient care and hospitalisation, respectively.13 Time from liver transplantation was classified as very long term (more than 10 years from liver transplant)10 and very short term (1 year or less from liver transplant), whereas the terms long and short term were adopted if the patients had been transplanted for more or less than 5 years, respectively.22 Management of single immunosuppression therapy was classified as follows: no change, reduction or discontinuation. For patients on double immunosuppression, reduction was defined as reduction of at least one immunosuppressive drug and/or discontinuation of one medication, while discontinuation was defined as discontinuation of both drugs.
The main outcome was patient death, while secondary outcomes were ARDS diagnosis23 and hospitalisation. All the data were entered in an electronic dataset using a standardised case report form.