key: cord-1046299-0b9oqy5m
authors: Shafran, Noa; Issachar, Assaf; Shochat, Tzippy; Shafran, Inbal Haya; Bursztyn, Michael; Shlomai, Amir
title: Abnormal liver tests in patients with SARS-CoV-2 or influenza – prognostic similarities and temporal disparities
date: 2021-02-24
journal: JHEP Rep
DOI: 10.1016/j.jhepr.2021.100258
sha: fed94d79b98827642ec8c14db61cdce350cc5e2c
doc_id: 1046299
cord_uid: 0b9oqy5m

BACKGROUND & AIMS: Abnormal liver tests are common in patients with severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) infection, but a possible direct role of the virus in liver injury and its association with short-term outcomes are controversial. Therefore, we aimed to compare the pattern of abnormal liver tests in SARS-CoV-2 patients with those of patients infected with influenza, a non-hepatotropic respiratory virus, and their association with worse outcomes during hospitalization. METHODS: A retrospective cohort study of 1737 hospitalized patients (865 with influenza and 872 with SARS-Cov-2) in a tertiary medical center. We defined abnormal liver tests as GPT or GOT ≥40IU/ML at any time-point during hospitalization. RESULTS: Abnormal liver tests were mild-moderate in the majority of patients regardless of infection type, but the majority of patients with influenza had a transaminases peak earlier during hospitalization compared to patients with SARS-Cov-2. Abnormal liver tests correlated with markers of severe disease in either influenza or SARS-Cov-2 infections, and were associated with death, occurring mainly in patients with severe liver tests abnormalities (>200IU/L) (38.7% and 60% of patients with influenza or SARS-Cov-2, respectively). In multivariate analysis, controlling for age, gender, lymphopenia and CRP, liver tests abnormalities remained significantly associated with death for influenza (OR= 4.344, 95% CI 2.218-8.508) and SARS-Cov-2 (OR= 3.898, 95% CI 2.203-6.896). These results were confirmed upon propensity score matching. CONCLUSIONS: Abnormal liver tests during hospitalization with SARS-Cov-2 or influenza infections are common, may differ in their time-course and reflect disease severity. They are associated with worse outcomes, mainly in patients with severe liver test abnormalities, regardless of infection type.

Background & Aims: Abnormal liver tests are common in patients with severe acute respiratory syndrome corona virus 2 (SARS-CoV-2) infection, but a possible direct role of the virus in liver injury and its association with short-term outcomes are controversial. Therefore, we aimed to compare the pattern of abnormal liver tests in SARS-CoV-2 patients with those of patients infected with influenza, a non-hepatotropic respiratory virus, and their association with worse outcomes during hospitalization. Methods: A retrospective cohort study of 1737 hospitalized patients (865 with influenza and 872 with SARS-Cov-2) in a tertiary medical center. We defined abnormal liver tests as GPT or GOT ≥40IU/ML at any time-point during hospitalization. Results: Abnormal liver tests were mild-moderate in the majority of patients regardless of infection type, but the majority of patients with influenza had a transaminases peak earlier during hospitalization compared to patients with SARS-Cov-2. Abnormal liver tests correlated with markers of severe disease in either influenza or SARS-Cov-2 infections, and were associated with death, occurring mainly in patients with severe liver tests abnormalities (>200IU/L) (38.7% and 60% of patients with influenza or SARS-Cov-2, respectively). In multivariate analysis, controlling for age, gender, lymphopenia and CRP, liver tests abnormalities remained significantly associated with death for influenza (OR= 4.344, 95% CI 2.218-8.508) and SARS-Cov-2 (OR= 3.898, 95% CI 2.203-6.896). These results were confirmed upon propensity score matching. Conclusions:

Abnormal liver tests during hospitalization with SARS-Cov-2 or influenza infections are common, may differ in their time-course and reflect disease severity. They are associated with worse outcomes, mainly in patients with severe liver test abnormalities, regardless of infection type.

COVID-19 is a serious global health pandemic, the causative agent of which is SARS-Cov-2.

Abnormal liver tests are common among SARS-Cov-2 infected patients and are often associated with worse outcomes. Here we compare the pattern of abnormal liver tests and their association with disease severity between two major non-hepatotropic respiratory viruses: SARS-Cov-2 and influenza. We show that abnormal liver tests are common in both infections, may slightly defer in their kinetics and are associated with worse outcomes, especially in patients with severe liver tests abnormalities. These results strongly suggest that abnormal liver tests in SARS-Cov-2 patients reflect disease severity, rather than a virusmediated direct liver injury, and should be closely followed in admitted patients.

• Abnormal liver tests are common in patients infected with SARS-Cov-2 and associated with worse outcomes (1), but now affecting most countries in the world (2) . Although the respiratory system is the main target of the virus, SARS-Cov-2 often triggers a systemic immune-mediated response that might result in injury to various organs, such as the kidneys, heart or liver (3, 4) . Recent reports indicate that hepatic injury is not uncommon among patients with COVID-19 (5) (6) (7) , and further suggest that abnormal liver tests are associated with increased mortality and should therefore be carefully monitored during hospitalization (8) (9) (10) . However, the predictive value and the association of abnormal liver tests with worse outcomes in patients with COVID-19 is still controversial (11, 12) .

Interestingly, SARS-coronavirus-associated hepatitis has been reported well before the present pandemic (13) . Furthermore, the liver might also be collaterally damaged by infections with other respiratory viruses, such as influenza (14) . Although few reports have suggested that certain strains of influenza A in children are possibly hepatotropic and might promote liver injury by directly targeting the hepatocytes (15), the widespread concept favors an immune-mediated mechanism(16), medication related hepatotoxicity, or hypotension that might result in hepatic ischemic injury.

We speculate that liver injury in COVID-19 is rather a marker of disease severity as in other viral respiratory infections (17) . Accordingly, we aimed to investigate the prevalence and natural course of abnormal liver tests, as well as their association with the composite outcome of mechanical ventilation or death or death, in patients with COVID-19 as compared to patients with influenza infection.

J o u r n a l P r e -p r o o f

This retrospective study is based on prospectively collected data of patients older than 18 years admitted to our medical center from early 2018 to early January 2021, found to be positive for either influenza (A/B) or SARS-Cov-2 by RT-PCR. Positive RT-PCR patients for more than one of the examined viruses, or lacking full information on liver enzymes were excluded. Rabin Medical Center (RMC) Review Board (#RMC-20-0142) approved the study that was performed according to Helsinki declaration.

We defined abnormal liver tests, including aspartate transaminase (GOT) or alanine transaminase (GPT) as levels ≥ 40 (U/L). These values are close to the accepted values defined in the literature (https://gi.testcatalog.org).

The primary outcomes of the study were defined as death (during hospitalization or within 3 days after discharge) or a composite of mechanical ventilation or death during hospitalization.

The following data were prospectively collected from the electronic medical records of patients included in the study: Basic characteristics, such as age, gender, body mass index (BMI), date of admission and outcomes (mechanical ventilation, length of hospitalization, discharge, transfer to ICU or death). Background liver disease was defined as documented cirrhosis, viral hepatitis or fatty liver (either previously recorded in the electronic files or observed by imaging during hospitalization), and major cardio-vascular diseases were defined as known ischemic heart disease, hypertension or diabetes. Clinical parameters recorded during hospitalization, including minimal blood oxygen saturation (BOS min ), maximal fever, minimal systolic blood pressure (SBP min ), as well as the presence of inhospital pneumonia, treatment with anti-viral or anti-microbial agents were collected from the electronic medical files. Laboratory data of liver enzymes were extracted at 4 time points:

on admission, last test before discharge, as well as maximum and minimum levels during hospitalization. In some cases, where there were less than 4 separate assessments, these time were extracted from the patients' electronic files.

We used SAS version 9.4 and GraphPad PRISM 9 software. Normality tests were conducted upon all variables. Due to the non-normal distribution of our variables, we used the nonparametric Wilcoxon and Kruskal Wallis tests when appropriate and median and interquartile range (IQR) are presented. Chi-square or Fisher's exact tests were compared categorical variables between study groups, accordingly. Two-sided p<0.05 was considered statistically significant.

The patients cohort was divided into two RT-PCR-based viral diagnosis groups and then further divided according to their liver enzyme status. Baseline characteristics, laboratory tests and basic information regarding hospitalization were compared between the groups and sub-groups. Univariate and multivariate regression models were constructed to estimate predictors for the primary outcome. Variables previously described found to be associated with the aforementioned outcomes, such as low lymphocyte counts, high CRP levels, age or gender (18) (19) (20) , as well as variables that were found to significantly associate in the univariate analyses, were incorporated into a Cox regression model. Odd ratios (ORs) with 95% confidence intervals (CI) were calculated. Logistic regression was used to calculate

ORs.

As a sensitivity analysis, propensity score matching was used to identify a cohort of patient 

In order to validate that the abnormal liver tests were by large transient and likely related to the acute illness, we compared the highest with the lowest values during hospitalization.

There was a clear and statistically significant difference between the highest and the lowest levels of liver tests during hospitalization, for patients with abnormal values, for both, influenza and SARS-Cov-2 infections (Fig S2) .

We next analyzed the timing of peak abnormal liver enzymes during hospitalization (Fig 1) .

GOT level peaked by day 4 of hospitalization in ~80% of patients with influenza vs. ~60% of patients with SARS-Cov-2 and between days 6-16 of hospitalization in ~16% of patients with influenza vs. ~30% of patients with SARS-Cov2. The GPT peak was recorded by day 4 in ~70% of patients with influenza vs. ~55% of patients with SARS-Cov-2 and between days 6-

Patients' demographics and the severity of their disease according to liver tests were subsequently analyzed ( (Table S1 ).

Routinely used laboratory parameters to evaluate disease severity, CRP and albumin levels,

were associated with the composite outcome in both infections. Importantly, the same was true for abnormal liver tests (GPT, GOT or GGT), all strongly associated with the composite outcome in the two groups of infected patients.

Liver test abnormalities incorporated in a multivariate regression analysis, utilizing patients'

age and gender as well as CRP and lymphocyte count (Fig 2) , were found to be significantly 

Secondary analysis for verification was done using propensity score matching. Liver enzymes were predictive for an outcome of intubation or death in both viruses in the matched cohorts. We next plotted the peak levels of GOT or GPT recorded during hospitalization against minimal albumin or maximal CRP values for each patient in our cohort (Figs S3,S4 ).

There was an inverse statistically significant correlation between liver tests and albumin levels and a linear statistically significant correlation between liver tests and CRP levels for GOT or GPT. This suggests that liver test abnormalities correlate well with other markers of disease severity.

Percentage of patients who achieved the composite outcome of mechanical ventilation or death, or an outcome of death, correlated well with the severity of liver tests abnormalities ( Fig 3A) . We categorized patients as having normal liver enzymes (GPT or GOT<40IU/L), mild to moderate liver test abnormalities (at least one enzyme ≥40IU/L but <200IU/L) or severe liver test abnormalities (at least one of the enzymes ≥200IU/L). Disease severity or worse outcomes parameters were significantly more common among patients with abnormal liver tests regardless of the type of infection, in line with other parameters, both clinical or laboratory, known to be associated with disease severity.

Therefore, it is reasonable to speculate that abnormal liver tests are a surrogate marker of disease severity and worse outcomes in patients hospitalized due to acute respiratory viral infection, and that this is not a property unique to a particular virus. In support of this, liver enzymes were all found to be inversely correlated with the minimal value of serum albumin and linearly correlated with maximal CRP levels recorded during hospitalization, two other well-established markers for disease severity.

Our study indicates that patients with severe abnormal liver tests (≥200 IU/L) are at the highest risk of worse outcomes, regardless of infection type. This is in line with a recent report from a large cohort of SARS-Cov-2 patients in the US, indicating that in the 6.4% of patients with severe abnormal liver tests (>5 times normal range), worse outcomes should be anticipated (22) . Still, the majority of our patients with abnormal liver tests presented with only mild-moderate liver enzymes abnormalities.

Several mechanisms may explain liver biochemical abnormalities during non-hepatotropic viral infection, but the leading theory is that liver injury is immune mediate, resulting from molecular mimicry between viral and hepatocyte antigens (16) . However, a recent study has suggested that SARS-Cov-2 contributes to hepatic impairment by directly infecting the liver resulting in a typical histological signature (23) . These authors related relatively mild J o u r n a l P r e -p r o o f alterations in transaminase levels to hepatic impairment, reflected by a low albumin level, and to massive apoptosis observed in few liver biopsies. Nevertheless, this study has recently been criticized (24, 25) , arguing that the relatively mild abnormal liver tests do not reflect true liver injury, usually defined by a much higher elevations in transaminases (26) .

Moreover the observed low albumin levels could reflect the severity of the disease rather than liver synthetic dysfunction. Indeed, our study suggests that abnormal liver tests correlate well with low albumin level as well as with other markers of disease severity, such as CRP and that in most infected patients with abnormal liver tests, the impairment is mild and is not virus specific.

Although this study includes a relatively large number of patients with an ample of clinical and laboratory data, it also has several limitations: First, it is retrospective and not all patients were systematically tested for liver enzymes, and we had no control on the timing by which these tests were taken for each patient. In addition, since the COVID-19 pandemic began only in 2020 and there were no recorded cases of influenza infections during the following winter of 2020/2021, we compared SARS-Cov-2 to influenza infected patients admitted to our medical center during separate period of times. Second, we had no access to laboratory results prior to hospitalization and could not accurately assess whether the observed abnormal liver tests during hospitalization is entirely new. We have partially overcome this pitfall, by

showing that the peak in abnormal liver tests is significantly higher than the nadir during hospitalization, suggesting that at least in the majority of patients, the maximal abnormal liver tests values are related to the acute disease and not to an underlying liver problem.

Third, the cutoff value of 40IU/L for a definition of elevated GPT and GOT levels is largely arbitrary and was not adjusted for age, weight and gender. However, these cutoffs were used in previous studies (23) , and by large represent values in the range observed in 95% of the healthy population. In addition, the reason that we have not included the ALKP and GGT values in our primary analysis is that these ALKP is not necessarily liver-specific and GGT does not necessarily reflect a direct liver injury.

In summary, in this study we show that abnormal liver tests are quite common and appear with similar frequency among hospitalized patients with either influenza or SARS-Cov-2

infections, although the timing of abnormal liver tests peak may be somewhat delayed in patients with SARS-Cov-2. The abnormal liver tests correlate with other markers of disease severity in the two types of infection and are associated with worse outcomes. Although our results suggest that abnormal liver tests do not necessarily reflect a direct and significant liver injury, but is rather a consequence of a systemic inflammatory response, we believe that liver J o u r n a l P r e -p r o o f 

should be routinely taken in such hospitalized patients, and that abnormal values should alert the treating physician to monitor the patient more intensively

List of abbreviations: Severe acute respiratory syndrome corona virus 2 (SARS-CoV-2)

Coronavirus disease 2019

aspartate transaminase (GOT); alanine transaminase (GPT); gamma-glutamyl transferase (GGT); minimal blood oxygen saturation

minimal systolic blood pressure (SBP min ); white blood cell (WBC) count; C-reactive protein (CRP)

Clinical Characteristics of Coronavirus Disease 2019 in China

Coronavirus Disease (COVID-19) In

Epidemiological and clinical characteristics of 99 cases of 2019 novel coronavirus pneumonia in Wuhan, China: a descriptive study

Clinical features of patients infected with 2019 novel coronavirus in Wuhan, China

Manifestations and prognosis of gastrointestinal and liver involvement in patients with COVID-19: a systematic review and meta-analysis

Interrelationship Between Coronavirus Infection and Liver Disease

Clinical characteristics of non-ICU hospitalized patients with coronavirus disease 2019 and liver injury: A retrospective study

Abnormal Liver Tests in COVID-19: A Retrospective Observational Cohort Study of 1,827 Patients in a Major U.S. Hospital Network

Longitudinal Association Between Markers of Liver Injury and Mortality in COVID-19 in China

Multicenter analysis of clinical characteristics and outcomes in patients with COVID-19 who develop liver injury

Liver involvement is not associated with mortality: results from a large cohort of SARS-CoV-2-positive patients

Liver tests abnormalities in COVID-19: trick or treat?

SARS-associated viral hepatitis caused by a novel coronavirus: report of three cases

Liver involvement during influenza infection: perspective on the 2009 influenza pandemic

Acute hepatitis and liver failure associated with influenza A infection in children

Systemic viral infections and collateral damage in the liver

Transaminase levels reflect disease severity in children ventilated for respiratory syncytial virus (RSV) bronchiolitis

Predictors for Severe COVID-19 Infection

Clinical characteristics of 113 deceased patients with coronavirus disease 2019: retrospective study

Clinical course and risk factors for mortality of adult inpatients with COVID-19 in Wuhan, China: a retrospective cohort study

Abnormal Liver Function Tests in Patients With COVID-19: Relevance and Potential Pathogenesis

Acute Liver Injury in COVID-19: Prevalence and Association with Clinical Outcomes in a Large

SARS-CoV-2 infection of the liver directly contributes to hepatic impairment in patients with COVID-19

Is the liver merely a bystander to severe disease?

SARS-CoV-2 related liver impairmentperception may not be the reality

Diagnosis and monitoring of hepatic injury. II. Recommendations for use of laboratory tests in screening, diagnosis, and monitoring

Saturation% (min) (median, IQR)

Albumin (mg/dL) (median, IQR)

Lymp. min (median, IQR)

GPT max (median