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
Liver injury is a common complication of infection by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus. The utility of laboratory hematology data in the diagnosis and risk stratification of patients with coronavirus disease 2019 (COVID-19) has not been comprehensively examined.
To address the following. (1) Are the abnormalities in hematologic parameters seen in the general population of patients with COVID-19 also seen in those patients with associated liver injury? (2) Is liver injury in COVID-19 a sign of severe disease and does liver injury correlate with hematologic markers of severe disease? And (3) What is the quality of this evidence?
To address these questions, a comprehensive systematic review was performed. We searched the peer reviewed medical literature using MEDLINE (PubMed interface), Web of Science, and EMBASE for cohort studies that specifically addressed liver injury and COVID-19 without limitation of date of publication or language. A quality assessment of the studies was performed using the Newcastle-Ottawa Scale.
Thirty-two articles were suitable for inclusion in our systematic review. These included 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 helpful in distinguishing COVID-19 with liver injury from COVID-19 without liver injury. ALC and d-dimer were identified as being 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.
Our study supports the use of select hematologic parameters in diagnosis and risk stratification of liver injury in COVID-19 patients. Although of overall high quality, the current medical literature is limited by the small number of studies with high statistical power and the variable definition of COVID-19 liver injury in the literature.
Core Tip: The use of laboratory hematology data as biomarkers of disease has not been examined for coronavirus disease 2019 (COVID-19) patients with liver injury, and the clinical significance of liver injury in COVID-19 is unclear. By means of a systematic review we showed that blood cell count, absolute neutrophil count, absolute lymphocyte count (ALC), and hemoglobin are of potential use in identifying liver failure in COVID-19. ALC and d-dimer have potential utility in distinguishing severe from non-severe disease in patients with liver injury. Our findings provide a rationale for further studies with sufficiently large numbers of patients and rigorous definition of liver injury to validate these findings.