GGT Level as a New Biomarker of COVID-19 Infection; a Systematic Review and Meta‑Analysis Comparing Intensive Care Unit (ICU) Patients with Non-ICU Cases

Gamma-glutamyl transferase (GGT) is an enzyme found in many body organs, and its highest concentration is found in the liver. The level of GGT is increased following liver damage in different diseases. This systematic review and meta-analysis was performed to evaluate GGT levels in COVID-19 patients and determine its predictive role in diagnosing the severity of the disease. The methods used in this systematic review were performed by the PRISMA checklist instructions. Two independent researchers searched international databases (PubMed, Web of Science, Scopus, and Google Scholar) to find related studies published in English from the time of the COVID-19 pandemic to October 2021. Stata software version 11 (StataCorp, College Station, TX, USA) was used for statistical analysis. Serum GGT level in ICU patients was 18.19 units higher than in other patients. This difference was statistically significant. Also, ALT and AST levels among ICU patients were higher than patients in other wards, which showed a statistically significant difference. GGT seems to be a good predictor for the severity of COVID-19. Laboratory data in hospitalized patients with COVID-19, including serum levels of GGT, ALT, and AST, play an essential part in predicting poor outcomes, especially among ICU patients. Key words: Gamma glutamyl transferase, COVID-19, biomarker, systematic review, meta-analysis