Copyright ©The Author(s) 2021.
World J Gastroenterol. Sep 21, 2021; 27(35): 5919-5931
Published online Sep 21, 2021. doi: 10.3748/wjg.v27.i35.5919
Table 1 Main studies reporting liver involvement in patients without pre-existing liver disease
Liver involvement criteria
Patients with liver involvement, n (%)
Main findings
Fan et al[33]China148ALT > 40 U/L or AST > 35 U/L 55 (37.2)Abnormal liver function is common in COVID-19 inpatients, leading to a longer hospital stay
Goyal et al[17]United States375ALT > 40 U/L120 (32)Mechanically ventilated patients more likely to have liver involvement.
Lenti et al[29] Italy100ALT or GGT > 50 U/L58/93 (62.4)Liver involvement correlate to higher mortality and ICU need in those who develop ARDS
Medetalibeyoglu et al[32]Turkey554ALT or AST > 40 U/L153 (27.6)Higher rate of moderate-to-severe pneumonia and ICU admission need in patients with liver involvement
Phipps et al[31]United States2273ALT > 50 U/L537 (24)Severe liver involvement was rare (6.4%) and led to worse outcomes (ICU admission, higher mortality)
Ponziani et al[30]Italy515AST > 45 U/I orALT > 45 U/I orGGT > 61161 (31.3)No cases of severe liver injury in this cohort. Liver involvement was generally mild and, although correlated to a higher need of ICU care, not associated to higher mortality
Richardson et al[7]United States5700ALT > 602176 (39)Acute liver injury occurred in 1% of the included patients and was associated with higher mortality
Schattenberg et al[28]Germany44ALT >50 U/L6/38 (15.8)Severe liver involvement was rare (9%), with AST more commonly deranged than ALT
Table 2 Main studies reporting outcomes in patients with pre-existing chronic liver disease
Patients with CLD, n (%)
Main findings
Bajaj et al[40]United States27237 (13.6)Higher mortality in cirrhotic COVID-19 positive patients
Hashemi et al[41]United States36369 (19)CLD patients had higher ICU admission and mechanical ventilation rate. CLD was a predictor of mortality
Iavarone et al[42]Italy5050 (100)COVID-19 infection led to liver function deterioration. CLD patients had increased mortality
Marjot et al[43]International1365745 (54.6)CLD correlate to higher mortality rate according to the CPT class. ALD was an independent risk factor for mortality
Qi et al[39]China2121 (100)Respiratory failure was the cause of death in most patients
Singh et al[37]United States25060 (46.1)Pre-existing CLD patients had higher hospitalisation and mortality rates
Sarin et al[38]International228228 (100)Decompensation of pre-existing CLD occurred in one fifth of cirrhotic patients
Table 3 Main studies reporting outcomes in liver transplant patients
Patients with LT
Main findings
Bhoori et al[45]Italy151 (COVID status unknown)151 (100)3 deaths recorded in long-term LT recipient on low immunosuppressant dose
Belli et al[47]International103103 (100)Mortality might correlate with age and longer time since LT
Donato et al[49]Italy640 (8 COVID positive)640 (100)Low prevalence of infection in LT patients who adhere to preventive measures
Lee et al[48]United States3838 (100)High mortality in LT patients regardless of time since transplant
Pereira et al[46]United States9014 (15)Solid organ transplant recipient had more severe outcomes
Webb et al[50]International778151 (19.4)LT patients did not have a higher mortality, ICU admission or hospitalisation rate; age and comorbidities correlated with outcomes
Table 4 Summary of the main studies reporting coronavirus disease 2019 related spleen dysfunction
Patients with spleen involvement, n (%)
Main findings
Feng et al[54]China66 (100)ACE2 expression on tissue-resident CD169+ macrophages in spleen; viral NP antigen found in ACE2+ cells in spleen; direct damage of spleen tissue (lymph follicle depletion, splenic nodule atrophy, lymphocyte reduction, etc.)
Remmelink et al[55]Belgium1711 (65)SARS-CoV-2 RNA detected in spleen autopsy samples by RT-PCR assay
Sekulic et al[56]United States22 (100)SARS-CoV-2 RNA detected at high level in spleen FFPE samples by RT-PCR assay
Han et al[58]China7356NAExpression of ACE2 in spleen tissue (lower than in other tissues), without difference according to sex
Li et al[59]China31NAExpression of ACE2 in spleen tissue (lower than in other tissues), without difference according to sex and age
Xu et al[60]China1010 (100)Decrease in spleen cell composition with decrease in lymphocyte components, white pulp atrophied, lymphoid follicles decreased or absent, increase in red pulp to white pulp ratio
Menter et al[61]Switzerland216 (29)Acute splenitis and/or septic neutrophilic leucocytosis of the red pulp, suggesting vascular disfunction in patients with COVID-19
Lax et al[62]Austria1110 (90)White pulp atrophy due to lymphocyte depletion, areas of haemorrhage with acute or chronic congestion
Duarte-Neto et al[63]Brazil55 (100)Lymphoid hypoplasia in 100%, red pulp haemorrhages in 60%, splenitis in 40%, extramedullary haematopoiesis in 50%, endothelial changes in 80%, vasculitis and arterial thrombus in 20%
Lenti et al[29]Italy6355 (87.3)IgM memory B cell depletion that correlates with increased mortality and superimposed infections
Kaneko et al[65]United States1111 (100)Loss of spleen germinal centres due to depletion of Bcl-6+ germinal centre B cells and Bcl-6+ germinal centre T follicular helper cells, resulting in a dysregulated humoral immune response