Published online Apr 28, 2021. doi: 10.13105/wjma.v9.i2.193
Peer-review started: January 28, 2021
First decision: February 24, 2021
Revised: March 31, 2021
Accepted: April 23, 2021
Article in press: April 23, 2021
Published online: April 28, 2021
Hematology laboratory testing has an established role in risk stratification in patients with coronavirus disease 2019 (COVID-19) disease. Liver injury is common in patients with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. The utility of hematology laboratory data in diagnosis and risk stratification of patients with COVID-19-related liver injury is unclear.
To what degree are the abnormalities in hematologic parameters seen in the general population of patients with COVID-19 also seen in the subpopulation of patients with associated liver injury? Is liver injury in COVID-19 indicative of severe disease. Does liver injury correlate with hematologic markers of severe disease? What is the quality of literature that addresses these questions?
The objectives of this study were: To determine the extent to which previously reported hematologic abnormalities are seen in patients with COVID-19-associated liver injury; to assess whether liver injury in COVID-19 is a sign of severe disease, and the extent to which liver injury correlates with markers of severe disease; and based on the extant literature, to determine the quality of this evidence.
This study was conducted as a Preferred Reporting Items for Systematic Reviews and Meta-Analyses-compliant systematic review. We extracted information from cohort studies related to the topic of liver injury in COVID-19 in which laboratory hematology data were included.
In all, 32 articles were included in the systematic review, which consisted of 22 articles with a cohort of COVID-19 patients with liver injury; 5 comparing non-severe vs severe COVID-19 populations in which liver injury was addressed and 5 other cohort studies with a focus on liver injury. White blood cell count, absolute neutrophil count, absolute lymphocyte count (ALC), and hemoglobin were the parameters most useful to distinguish COVID-19 with liver injury from COVID-19 without liver injury. ALC and d-dimer were potentially useful in distinguishing non-severe from severe COVID-19. Liver injury was more frequently seen in cohorts with severe disease. Most studies were of high quality (24/48, 86%) with 4/28 (14%) of moderate quality and 0 of low quality.
The use of select hematologic parameters in diagnosis and risk stratification of liver injury in COVID-19 patients appears warranted. The relevant literature is high quality, but is limited by the small number of studies with high statistical power and the variable definition of COVID-19 liver injury in the literature.
Future studies, preferably with a prospective design, large numbers of patients, and rigorous definition of liver injury would be useful to validate these findings.