1
Introduction/Abstract
During the early stages of the COVID-19 pandemic, EASL and ESCMID published a position
paper to provide guidance for physicians involved in the care of patients with chronic
liver disease. In the meantime, many countries and healthcare systems have been, or
are still overwhelmed by the pandemic, significantly impacting on the care of this
group of patients, whilst others have started to return towards their usual routine.
In addition, many studies have been published focusing on how COVID-19 may affect
the liver and how pre-existing liver diseases might influence the clinical course
of COVID-19. While many aspects remain poorly understood, it has become increasingly
evident that pre-existing liver diseases and liver injury during the course of the
disease have to be kept in mind when caring for patients with COVID-19. Thus, this
review should serve as an update on the previous position paper summarizing the evidence
for liver disease involvement during COVID-19 and also provide some recommendations
on how to return to routine care wherever possible.
2
Pre-existing liver disease as risk factor for COVID-19
Patients with chronic liver diseases per se do not appear to be over-represented in
cohorts of patients with COVID-19 where they represent less than 1% of reported cases
[1, 2]. These observations suggest that patients with chronic liver disease are not
at increased risk of contracting SARS-CoV-2. However, risk of infection and/or risk
for severe course of COVID-19 may be different depending on the nature of the chronic
liver disease and the presence or absence of advanced fibrosis or cirrhosis. We will
therefore summarize current evidence for different liver diseases regarding the risk
for SARS-CoV-2 infection and for a severe course of COVID-19.
Metabolic-dysfunction associated fatty liver disease (MAFLD)
Obesity represents a significant risk factor for a severe course of COVID-19 [3, 4]
with severe pneumonia being particularly increased in obese men [3]. While the precise
mechanisms driving this association remain unclear, it has been postulated that adipose
tissue may serve both as a viral reservoir and also an immunological hub for the inflammatory
response [5]. Similarly, other metabolic syndrome elements such as hypertension and
diabetes are commonly observed in patients with severe COVID-19 [6]. As metabolic
dysfunction-associated fatty liver disease (MAFLD, previously known as non-alcoholic
fatty liver disease, NAFLD) [7] and non-alcoholic steatohepatitis (NASH) are closely
associated with these metabolic comorbidities, it is of relevance to identify whether
presence of MAFLD specifically predisposes to a more severe course of COVID-19. A
retrospective cohort of 202 patients with COVID-19 demonstrated an association between
MAFLD and disease progression defined as deteriorating dyspnoea, hypoxia or radiological
findings whilst in hospital [8]. This additional risk has been observed even in younger
patients with MAFLD [9] and in the absence of type 2 diabetes [10] and interestingly,
patients with MAFLD also appear to have a longer duration of viral shedding [8]. Within
patients with MAFLD, non-invasive fibrosis scores appear to correlate with higher
likelihood of developing severe COVID-19 illness, irrespective of metabolic comorbidities
[11], however, genetic polymorphisms implicated in the development and progression
of NASH do not appear to be associated with severe disease [12, 13]. In addition,
transcriptional activity of genes relevant for SARS-CoV-2-infection has not been found
to be increased in liver-tissues of MAFLD patients [14]. Larger analyses are needed
to determine whether MAFLD is an independent risk factors for a poor prognosis in
COVID-19 or whether the reported effects are due to the presence of confounding factors.
Chronic viral hepatitis
In contrast to metabolic liver disease, little or no evidence has emerged to suggest
that the presence of chronic viral hepatitis affects the COVID-19 disease course.
Data from both an international registry and from a multicenter cohort study in Italy
on COVID-19 outcomes in patients with chronic liver disease include patients with
viral hepatitis (23%-37%). However, despite both studies demonstrating associations
between severity of liver disease and poor outcome, it remains unknown whether the
presence of chronic viral hepatitis influences prognosis [15, 16].
Autoimmune hepatitis
In the previous position paper, we advised against the withdrawal of established immunosuppressive
therapy in patients with autoimmune liver disease [17] and a panel of experts on autoimmune
liver disease have subsequently given similar recommendations [18]. While there is
still little evidence to demonstrate that immunosuppressive therapy per se predisposes
to SARS-CoV-2 infection, a handful of observational studies have suggested an association
between corticosteroid use and a more severe COVID-19 disease course [[19], [20],
[21], [22], [23]]. The potential implications of these observations are discussed
below in more detail. Further data are needed to determine whether the specific risk
of COVID-19 is increased in patients with autoimmune hepatitis and the influence of
steroids and/or other immunosuppressive medications on outcome (see also Box 1
).
Box 1
Open questions for liver related basic/translational research regarding COVID-19
•
Risk factors for increased mortality in patients after liver transplantation
•
Role of pre-existing immune activation (e.g. in cirrhosis or MAFLD/obesity) in exacerbating
COVID-19 outcomes
•
Identification of central hubs for SARS-CoV-2 dissemination within the GI-tract and
fat tissues
•
Involvement of liver endothelium in promoting SARS-CoV-2 dissemination
•
Identification of direct and indirect effects of SARS-CoV-2 on hepatocytes/cholangiocytes
•
COVID-19 as a trigger for ACLF and decompensation in cirrhotic patients
•
COVID-19 induced thrombophilia as a contributor to progressive liver disease
Cirrhosis
Patients with liver cirrhosis are at increased risk for infections and associated
complications due to cirrhosis-associated immune dysfunctions, which is particularly
important for patients with decompensated cirrhosis. A recent case-series from China
reported that from 21 consecutive patients with pre-existing cirrhosis, 5 did not
survive SARS-CoV-2-infection [24] and specifically patients with Child-Pugh class
C cirrhosis were more likely to suffer a fatal course of COVID-19 [24, 25]. Another
case series from Italy documented 50 patients with cirrhosis and COVID-19; 26% of
these patients presented with MELD ≥15, increasing from 13% at the last documented
visit prior to SARS-Cov-2 infection. The 30 day mortality was 34%, with end-stage-liver
disease considered as the cause of death in only 5 patients (29%) whilst respiratory
failure due to COVID-19 accounted for death in 12 patients (71%) [15]. These data
are in line with observations from a European registry that reported the outcome of
103 patients with cirrhosis - nearly 40% died with patients with Child-Pugh class
C cirrhosis at the highest risk for a fatal course of COVID-19 (63%, n= 27) [16].
Similarly, multicentre hospital coding data in the USA demonstrated a significantly
higher risk of mortality from COVID-19 in patients with chronic liver disease compared
to those without, with the highest risk found in those with cirrhosis [26]. However,
these data did not have a contemporaneous comparison group of patients with cirrhosis
presenting with acute decompensation without COVID-19. Recently, a prospective multicentre
study compared outcomes between patients with cirrhosis and COVID-19 (n=37), cirrhosis
alone (n=127) and COVID-19 alone (n=108). Although rates of mortality or transfer
to hospice in patients with cirrhosis and COVID-19 was greater than COVID-19 alone
(30% vs 13%, p=0.03) there was no significant difference from cirrhosis alone (30%
v. 20%; p=0.11). The presence of acute-on-chronic liver failure (ACLF) was also similar
in the two cirrhosis groups (29.7% vs 22.8%) as was mortality in ACLF patients (55%
v. 36%; p=0.25) although the number of cases was small [27]. Taken together, currently
it is difficult to conclude that the occurrence of COVID-19 in cirrhosis patients
increases the risk of developing ACLF or mortality compared with those patients that
decompensate with cirrhosis due to other reasons. However, the mortality of cirrhosis
patients with COVID-19 is markedly greater than those that do not have cirrhosis.
Liver Transplantation (LT) recipients
The clinical course of COVID-19 in immunosuppressed transplant recipients may differ
from those in non-immunosuppressed patients [28]. Indeed, while hepatocellular injury,
as characterized by elevated serum aminotransferases, appears to be relatively less
prevalent, acute kidney injury is more common in transplant recipients with COVID-19,
possibly due to the use of calcineurin inhibitors [28]. These findings will need confirmation
in larger case series; however, in line with the general risk factors for severe COVID-19,
elderly patients with comorbidities are among those with the highest risk within the
cohort of transplant recipients [28, 29]. Early reports from Italy described low mortality
rates in transplant recipients < 5% [20, 30], however subsequent analyses have reported
mortality rates in liver and other solid organ transplant recipients at around 25%
[28, [31], [32], [33], [34]]. The results of a prospective European study from 19
transplant centres were recently reported [35] including 57 LT recipients with confirmed
SARS-CoV-2 infection. Overall and in-hospital case-fatality rates were 12% and 17%
respectively, which are similar to the expected mortality for patients with severe
COVID-19 infection. Five of the 7 patients who died had an underlying history of cancer.
Taken together the currently available data do not support the notion that transplantation
or specific immunosuppressive regimens significantly affect the risk for a severe
course of COVID-19 but those with underlying cancer may require special attention
[28, 31, 35].
3
Liver injury secondary to COVID-19
Deranged liver biochemistry of varying degrees is common in patients with COVID-19,
being found in 19-76% of cases [[36], [37], [38], [39], [40], [41]]. Most of these
studies report a predominantly hepatocellular pattern of liver injury with elevated
serum aminotransferases (rarely > 5 x upper limit of normal) although cholestatic
or mixed patterns of liver injury have also been reported. Importantly, this appears
to occur to a similar degree in patients with and without pre-existing liver disease
[26] and has also been documented in pregnant women in association with increased
levels of pro-inflammatory cytokines [42]. To what extent this liver injury is derived
from the direct effect of SARS-CoV-2, as opposed to a secondary phenomenon caused
by the broader disease course of COVID-19 remains to be elucidated. SARS-CoV-2 infection
of hepatocytes with subsequent mitochondrial disturbance and apoptosis has been suggested
[41], but requires confirmatory testing particularly since single cell RNA sequencing
has shown relatively sparse hepatocyte expression of the receptors necessary for viral
uptake [43]. Similarly, direct infection of cholangiocytes via angiotensin-converting
enzyme 2 (ACE2) has been posited as a potential mechanism for intrinsic liver injury
[44] but requires further investigation. Given the profound multi-systemic involvement
of COVID-19, particularly in the severe and critical forms of disease, liver injury
is likely to be multifactorial with contributions from systemic inflammation, intrahepatic
immune activation, microvascular thrombosis, hepatic congestion, perturbations of
the gut-liver-axis as well as drug toxicity [[45], [46], [47], [48]]. The prognostic
significance of deranged biochemistry in COVID-19 remains unresolved [49]; some groups
have demonstrated a strong correlation with duration of hospitalisation, organ failure
and intensive care unit admission [37, 41, 50] whilst others have failed to observe
any significant associations with outcome [39, 40].
4
Recommendations for the management of patients with chronic liver disease
In the aftermath of COVID-19 at its peak, there was an urgent need to anticipate and
plan for the wave of liver disease yet to come. This will be characterised by emergent
hepatic decompensation, increased dropouts from transplant waiting lists and a vast
back-log of deferred hospital visits and testing [51]. Clinicians and their institutions
should therefore be proactive in structuring their services to tackle these challenges
and strive to resume standard-of-care for patients with liver disease wherever possible.
Equally, it is important to embrace innovative technologies and methods of practice
developed during the pandemic which may continue to be of benefit to patients (e.g.
telemedicine use, remote monitoring) [52]. Combining standard of care with novel ideas
will help to mitigate against longer term consequences of the pandemic including missed
diagnosis, incomplete HCC screening, and progressive liver disease. Furthermore, in
light of accumulating evidence that baseline liver disease severity is associated
with poor outcomes from COVID-19 [15, 16], treatment of underlying liver disease may
represent one of the most important strategies to protect patients from the adverse
effects of any future SARS-CoV-2 infection. This in turn will further reduce the burden
on healthcare systems and allow more rapid return towards gold standard hepatology
practice (Fig 1
). The epidemiology of COVID-19 has proven unpredictable, but the burden of disease
is likely to expand and shrink episodically within populations for some time to come.
The approach to patient care must therefore be personalised and flexible, balancing
national dynamics of SARS-CoV-2 infection, the local resource availability, and the
severity of each individual patient's underlying liver disease. Lastly, with time,
it will be important to resume clinical trial enrolment wherever possible to allow
the field to advance despite unprecedented global events.
Fig. 1
Liver disease progression and poor outcomes from SARS-CoV-2 infection are closely
associated. There must therefore be a concerted effort to resume standard of care
and restore hepatology/transplantation services in order to improve patient outcomes.
Fig. 2
Summary of recommendations.
Specific recommendations
MAFLD
•
Patients should be made aware of potential adverse metabolic and hepatic consequences
of social isolation including more sedentary lifestyles and increased consumption
of processed foods.
•
Preventing liver disease progression through intensive lifestyle intervention, including
nutritional guidance, weight loss advice, and diabetes management may help prevent
the development of a severe disease course with future SARS-CoV-2 infection.
•
Treatment of arterial hypertension should continue in accordance with existing guidelines.
There is currently no evidence showing that angiotensin converting enzyme inhibitors
(ACEIs) or angiotensin receptor blockers (ARBs) increase the risk of SARS-CoV-2 infection
or the risk of developing severe complications or death from COVID-19 [53].
•
Early admission should be considered for all patients with MAFLD who become infected
with SARS-CoV-2.
Viral hepatitis
•
Continue treatment of chronic hepatitis C virus (HCV) and chronic hepatitis B virus
(HBV) if already receiving treatment.
•
Use telemedicine/local laboratory testing for follow-up visits in patients receiving
antiviral therapy, send follow-up-prescriptions by mail and supply extended prescription
supplies including full course of direct acting antiviral (DAA) medications to complete
HCV treatment if this has been initiated. However, patients with poor compliance with
medications should be considered for directly observed treatment protocols.
•
In patients without COVID-19, treatment for HCV and HBV should be initiated according
to general guidelines [54, 55].
•
Given the unknown impact of interferon alpha on systemic inflammation associated with
COVID-19, alternative agents should be considered when initiating treatment for patients
with HBV during the COVID-19 pandemic.
•
In patients with COVID-19, initiation of treatment for HBV and HCV is usually not
warranted and should be deferred until recovery from COVID-19.
•
In patients with COVID-19 in whom there is evidence of high disease activity (flare)
or clinical suspicion for severe acute HBV hepatitis, a decision to initiate antiviral
therapy should be made on a case-by-case basis in consultation with a specialist.
•
In patients with chronic, occult or resolved HBV and COVID-19 receiving corticosteroids,
tocilizumab or other immunosuppressive agents, consider the use of antiviral therapy
to prevent viral flare or reactivation.
•
Continue to work towards the WHO goal of eliminating viral hepatitis by 2030 by trying
to adapt the cascade-of-care to the new coronavirus situation and make modifications
for safe delivery of services according to the local requirements.
Alcohol associated liver disease
•
Chronic alcohol consumption may increase susceptibility of acute respiratory distress
syndrome (ARDS) secondary to SARS-CoV-2 infection [56].
•
Social isolation can lead to new or increased alcohol consumption [57] and an increase
in alcohol related admissions including new hepatic decompensation should be anticipated
during and after periods of physical distancing.
•
Clinicians and institutions should therefore implement pre-emptive strategies such
as patient outreach and telephone alcohol liaison and cessation services.
•
Whilst introducing corticosteroids has shown benefit in the treatment of hospitalised
patients with COVID-19 requiring respiratory support [58], concerns remain that patients
who are already taking higher doses of corticosteroids may be more susceptible to
severe COVID-19 [19, 59]. These concerns must be considered when initiating corticosteroids
as a treatment for patients with severe alcoholic hepatitis.
•
Clinicians should be aware of circulating false online misinformation regarding the
protective effects of alcohol against SARS-CoV-2 leading to previous instances of
deliberate excess consumption [60].
Autoimmune liver disease
•
In patients with autoimmune liver disease, we currently advise against reducing immunosuppressive
therapy to prevent SARS-CoV-2 infection. Reductions should only be considered under
special circumstances (e.g. medication-induced lymphopenia, or bacterial/ fungal superinfection
in cases of severe COVID-19) after consultation with a specialist.
•
Whilst introducing corticosteroids has shown benefit in the treatment of hospitalised
patients with COVID-19 requiring respiratory support [58], concerns remain that patients
who are already taking higher doses of corticosteroids may be more susceptible to
SARS-CoV-2 infection and severe COVID-19 [19, 59]. To minimise systemic glucocorticoid
exposure we therefore recommend considering budesonide as a first-line agent to induce
remission in patients without cirrhosis who have a flare of autoimmune hepatitis [61].
•
In patients treated with corticosteroids who develop COVID-19, corticosteroid dosing
should be sufficient to prevent adrenal insufficiency. Addition of, or conversion
to dexamethasone should only be considered in patients with COVID-19 who require hospitalisation
and respiratory support [58].
•
There remains a paucity of data to make specific recommendations for patients with
primary biliary cholangitis, primary sclerosing cholangitis and IgG4-related disease.
•
All patients should receive vaccination for Streptococcus pneumoniae and influenza
Cirrhosis
•
Patients with cirrhosis are particularly vulnerable to both the consequences of SARS-CoV-2
infection and to the adverse effects of delayed or altered standard of care during
the COVID-19 pandemic.
•
Every effort should be made to resume the best standard of care for patients with
cirrhosis according to guidelines [62] wherever possible.
•
Patients with cirrhosis who are infected with SARS-CoV-2 are at high risk of new or
worsening hepatic decompensation, severe COVID-19 and death [15, 16].
•
All patients with new or worsening hepatic decompensation or acute-on-chronic liver
failure (ACLF) should be prioritised for SARS-CoV-2 testing even in the absence of
respiratory symptoms [16].
•
In those with cirrhosis who are admitted for reasons other than COVID-19, particular
effort should be made to manage these patients in a designated non-COVID-19 ward,
preferably in a side-room, in order to reduce the risk of nosocomial SARS-CoV-2 infection.
•
Guidelines on prophylaxis of spontaneous bacterial peritonitis, gastrointestinal haemorrhage,
and hepatic encephalopathy should be closely followed to prevent decompensation and
avoid admission [62].
•
Early admission should be considered for all patients with cirrhosis who become infected
with SARS-CoV-2.
•
Because of the potential of circulatory dysfunction, in particular in the pulmonary
circulation associated with COVID-19 [63], the use of vasoconstrictor therapy, which
is known to increase pulmonary pressure and decrease cardiac output, should be considered
with great caution among critically ill patients with cirrhosis and COVID-19.
•
Rapid clinical deterioration in patients with advanced liver disease and COVID-19
should prompt consideration of a symptoms-based approach using palliative care guidelines
[64].
•
All patients should receive vaccination for Streptococcus pneumoniae and influenza.
Liver transplant (LT) candidates
•
Patients on the LT waiting list with decompensated cirrhosis are at high risk of severe
COVID-19 and death following SARS-CoV-2 infection.
•
We therefore recommend LT centers aim to restore transplantation services following
the peak of the COVID-19 epidemic wherever possible.
•
In centers with ongoing resource limitations, LT should be prioritized for patients
with poor short-term prognosis including those with acute/acute-on-chronic liver failure
(ALF/ACLF), high model for end-stage liver disease (MELD) score (including exceptional
MELDs) and HCC at the upper limits of the Milan criteria.
•
The risk of SARS-CoV-2 transmission via liver transplantation remains unknown [65]
and therefore we currently recommend to test all donors for SARS-CoV-2 infection by
RT-PCR and recommend against using livers from SARS-CoV-2 infected donors [66].
•
We encourage LT centres to develop and improve local and global risk stratification
pathways for LT donors and recipients incorporating a combination of clinical history,
chest radiology, and SARS-CoV-2 testing [67] and ethical considerations regarding
transplantation activities and allocation [68].
•
Measures should be taken to reduce the risk of SARS-CoV-2 infection in the peri-transplantation
period. In areas of high disease burden, a COVID-19 free pathway through transplantation
should be implemented including strict social isolation for waiting list patients,
telephone screening for symptoms and exposures before admission, and perioperative
management in a designated clean ICU and post-LT ward [69].
•
Consent for diagnostic and therapeutic procedures related to transplantation should
include the potential risk of nosocomial COVID-19.
•
LT candidates should be made aware that infection with SARS-CoV-2 in patients undergoing
major surgery is associated with an increased risk of severe COVID-19 and death [70].
•
Living-donor transplantations should be considered on a case-by-case basis and include
careful risk stratification of donor and recipient incorporating a combination of
clinical history, chest radiology, and SARS-CoV-2 testing.
LT recipients
•
We advise against reduction of immunosuppressive therapy to prevent SARS-CoV-2 infection.
Reduction should only be considered under special circumstances (e.g. medication-induced
lymphopenia, or bacterial/fungal superinfection in case of severe COVID-19) after
consultation with a specialist.
•
Clinicians must be aware of the high reported rates of fear and anxiety regarding
COVID-19 in LT recipients and the barrier this may pose to compliance with immunosuppressive
medication and attendance at scheduled medical visits [71].
•
Drug levels of calcineurin inhibitors and mechanistic Target of Rapamycin (mTOR) inhibitors
should be closely monitored when they are administered together with drugs such as
hydroxychloroquine, protease inhibitors or alongside new trial drugs for COVID-19
as they emerge.
•
Early admission should be considered for all LT recipients who develop COVID-19
•
Risk factors for a severe course of COVID-19 in LT recipients may include underlying
malignancy, sarcopenia, graft dysfunction and metabolic comorbidities. However, the
individual contributions of these factors require further clarification.
•
All patients should receive vaccination for Streptococcus pneumoniae and influenza.
Hepatocellular carcinoma (HCC)
•
The specific risk of COVID-19 in patients with hepatocellular carcinoma remains undefined.
•
However, mortality from COVID-19 in cancer patients appears to be determined by age,
gender, and comorbidities as opposed to the use of cytotoxic chemotherapy or other
anticancer treatment [72].
•
Care should be maintained according to guidelines including continuing systemic treatments
and evaluation for liver transplantation.
•
Multidisciplinary HCC boards should continue to function remotely and provide treatment
recommendations
•
Full HCC surveillance should resume where possible. Where resources remain limited,
patients with increased risk, such as patients with elevated alpha-fetoprotein levels,
advanced cirrhosis, chronic hepatitis B, NASH/diabetes etc should be prioritised in
conjunction with the use of published HCC risk stratification scores.
5
Liver-related diagnostic procedures
Endoscopy
Endoscopic procedures are associated with an increased risk of disseminating SARS-CoV-2.
During esophagogastroduodenoscopy (EGD) or endoscopic retrograde cholangiography (ERC),
spreading of virus-containing droplets can occur. In addition, shedding of the virus
in the faeces increases the risk of dissemination during colonoscopy. Thus, depending
on the local COVID-19 burden, we recommend SARS-CoV-2 testing prior to endoscopic
procedures in all patients. In patients who test negative and in areas with low COVID-19
burden, EGD - to screen for and treat varices - and ERC - for duct dilatation or stent
replacement in patients after liver transplantation or patients with primary sclerosing
cholangitis - should not be delayed.
In patients with COVID-19, indications for endoscopic procedures should be limited
to emergencies such as gastrointestinal bleeding and bacterial cholangitis.
Ultrasound (HCC surveillance)
HCC surveillance should only be deferred based on available resources (including availability
of therapeutic options in case of HCC diagnosis) at the centre and the individual
risk assessment. Patients with increased risk (e.g. patients with elevated alpha-fetoprotein
levels, advanced cirrhosis, chronic hepatitis B, HCV-related cirrhosis (even after
cure), NASH/diabetes) should be prioritised if resources are limited.
In patients with COVID-19, HCC surveillance can be deferred until after recovery.
Liver biopsy
In areas with low COVID-19 burden, liver biopsies should be performed as indicated,
including grading/staging for MAFLD and chronic viral hepatitis and histological assessment
of elevated transaminases of unknown aetiology. In areas with high COVID-19 burden
or limited availability of resources, biopsy should be prioritised in patients with
severely elevated transaminases of unclear cause (e.g. ALT >5x upper limit of normal),
suspected transplant rejection and liver masses suspicious of malignancy.
In patients with COVID-19, liver biopsy may be performed based on the individual indication
for histological assessment. It has to be considered that treatment/care for COVID-19
may outweigh the diagnosis of co-existing liver disease and that systemic inflammation
associated with COVID-19 is likely to obscure aetiology-specific histologic characteristics.
As discussed above, liver function test abnormalities are common in patients with
COVID-19 particularly with more severe disease and routine liver biopsy in this context
is not required.
6
Liver specific considerations in the pharmacological management of COVID-19
The targeted management of COVID-19 is a rapidly evolving field with a plethora of
new or repurposed medications constantly shifting in and out of favour. In Europe
alone there are currently over 200 registered COVID-19 specific drug trials [73].
This number will no doubt continue to increase as we learn more about the pathophysiology
of the disease. It is beyond the scope of this updated position paper to comprehensively
review the potential therapeutic options for COVID-19. While some interventions, such
as infusion of convalescent plasma or favipiravir (recently approved in India) show
encouraging signals of efficacy, little is known with regards to liver-specific side
effects or contraindications. However, for some therapeutic agents there are liver-specific
considerations which we will discuss. Hepatologists must be mindful of the secondary
effects these drugs may have on the liver and continually evaluate the specific risks
and benefits conferred to their patients with underlying liver disease.
Remdesivir
Remdesivir is an adenosine-analogue that induces RNA chain termination and was initially
developed as an antiviral agent against Ebola. It has emerged as a promising treatment
candidate against COVID-19 being shown to reduce the duration of symptoms when used
early in the disease course [74, 75]. Despite preclinical investigations demonstrating
reversible aminotransferase elevations [76], use of remdesivir in controlled trials
has not demonstrated a significant impact on liver function tests compared with placebo.
In the largest randomised control trial to date, Beigel et al demonstrated no difference
in rates of aminotransferase elevation between patients taking remdesivir compared
with placebo (4% v. 5.9%) [74]. Similarly, Wang et al also showed comparable rates
of elevated transaminases between remdesivir and placebo groups [77]. Both trials
excluded patients with baseline ALT or AST >5x upper limit of normal and Wang et al.
also excluded patients with cirrhosis. Should remdesivir ultimately move into mainstream
use, caution should therefore be exercised in patients with advanced liver disease
or with severe baseline derangements in liver biochemistry, but otherwise transaminase
elevations do not appear to occur over and above what may be expected as part of the
typical disease course of COVID-19. Remdesivir is approved for the treatment of COVID-19
in several European countries.
Tocilizumab
Interleukin-6 (IL-6) appears to be a key driver of the “cytokine storm” leading to
significant lung and other organ damage in cases of severe COVID-19. Tocilizumab,
a humanized monoclonal antibody targeting IL-6 has therefore been postulated to counter
this dysregulated inflammation and has shown promise in retrospective series of COVID-19
by reducing the need and duration of organ support [78]. The liver side effect profile
of tocilizumab is well established due to its widespread use in rheumatoid arthritis
and other auto-inflammatory conditions. Mild serum aminotransferase elevations are
common and are usually self-limiting and asymptomatic [79], however, progressive jaundice
requiring liver transplantation has been reported [80]. Rarely, tocilizumab has been
associated with Hepatitis B virus reactivation [81] and therefore HBV serology should
form part of routine pre-treatment work-up.
Corticosteroids
There seems to be a dichotomous relationship between corticosteroids and COVID-19.
Whilst patients already taking corticosteroids may be at increased risk of adverse
outcomes from COVID-19, those with established severe disease seem to paradoxically
benefit from corticosteroid introduction. In patients with inflammatory bowel disease,
the use of corticosteroids has been associated with intensive care unit admission,
ventilator requirement and/or death [19]. Similarly, patients on maintenance glucocorticoids
for rheumatological conditions have an increased rate of hospitalisation following
SARS-CoV-2 infection [59]. As yet, small case series have been unable to draw definitive
conclusions regarding the risks posed by corticosteroid use in patients with autoimmune
hepatitis or after liver transplantation [31, 34]. In these patients, the risks of
hepatitis flares or graft rejection must be weighed against the potential risks of
developing severe COVID-19. Currently, we advise against routine reduction of immunosuppression
in AIH or LT recipients, including the use of steroids if required. Corticosteroids
however do appear to be a viable treatment option for patients with severe COVID-19
requiring respiratory support. In June 2020, the RECOVERY [58] trial reported that
dexamethasone reduced deaths by one-third in ventilated patients and by one fifth
in patients receiving supplemental oxygen. It is likely that this agent will be increasingly
used in the management of severe COVID-19 including in patients with pre-existing
chronic liver disease.
Anticoagulation
Patients with advanced liver disease are at increased risk of venous thromboembolism
[82]. Similarly, coagulopathy is a common abnormality in patients with COVID-19 and
has emerged as a major driver of morbidity and mortality, particularly in patients
with severe disease. Hospitalised patients with COVID-19 have alarmingly high rates
of venous thromboembolic disease with an observed incidence of 20% at day 7, and 42%
at day 21 despite thromboprophylaxis [83]. As well as macro-thrombotic events, COVID-19
is also associated with widespread micro-thrombosis and endothelial dysfunction contributing
to multiorgan failure in the terminal phase of the disease [84, 85]. The role of anticoagulation
in patients with COVID-19 has therefore been extensively investigated and has been
shown to improve outcomes in severe COVID-19 [86], although unified risk stratification
models and treatment thresholds have yet to emerge. Given that both advanced liver
disease and COVID-19 are both associated with a hypercoagulable state, it reasons
that SARS-CoV-2 infection in patients with cirrhosis may yield a cumulative risk of
prothrombotic complications. We therefore suggest that in this scenario patients should
be deemed at particularly high risk of thromboembolic events. Whilst historically
there have been reservations about the use of anticoagulation in patients with cirrhosis
and portal hypertension, systematic review has demonstrated no excess of bleeding
events in anticoagulated patients with cirrhosis and portal vein thrombosis [87].
Furthermore, anticoagulation may have antifibrotic properties [88] and even confer
a survival advantage in patients with cirrhosis [89]. Further reassurance is provided
by a recent multicentre Italian study in which 80% of patients with cirrhosis and
COVID-19 received thromboprophylaxis without any evidence of major haemorrhagic complications
[15]. Whilst thromboprophylaxis, typically with low molecular weight heparin (LMWH),
should form part of standard of care for all patients with cirrhosis admitted to hospital,
it remains to be determined whether patients with COVID-19 and cirrhosis should receive
early treatment with enhanced or therapeutic anticoagulation.