Association between Serum Total Bilirubin Level and Clinical Outcome of COVID-19 Infection: Protective Role of Bilirubin

Abstract

Background: Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) causes covid-19 disease. The disease is a multisystem and mosaic disorder that demonstrates extra pulmonary manifestations involving liver and other organs. Elevated blood bilirubin levels have been associated with poor covid-19 disease outcome. However, discrepancies prevail in these findings. The study aimed to evaluate the association between serum total bilirubin and direct bilirubin levels and clinical outcome of covid-19 infection. Materials and methods: This was a retrospective cross-sectional study. Data was obtained from medical records of patients admitted at Mount Kenya Hospital, Nyeri which was the designated county facility for diagnosis, treatment and management of covid -19 disease in Nyeri, Kenya. Data was obtained from patients’ files admitted between 01/04/2021-30/09/2021. Inclusion criteria: Positive covid -19 patients tested with real-time quantitative reverse transcription polymerase chain reaction test (rqRTPCR) and patients with serum total bilirubin and direct bilirubin levels done at admission. Exclusion criteria: Positive rqRTPCR covid-19 patients with incomplete medical records, positive covid-19 patients tested using rapid antigen test, patients with comorbidities, and pregnant women. Categorization of liver injury based on bilirubin levels: severe liver injury >5× ULN, moderate liver injury 3–5x ULN and mild liver injury 1–2x ULN. Categorical data were presented as frequencies and the chi-square test was applied to test for associations. P-value < 0.05 was considered statistically significant. Results: There was no statistical significance between serum levels of total bilirubin (P=0.390), direct bilirubin (P=0.272) and covid-19 clinical outcome (survival or non-survival) and severity. Conclusion and Recommendations: Serum total bilirubin and direct bilirubin levels has no significant association with covid-19 disease outcome and severity and thus are not reliable prognostic markers in our setting and in patients without preexisting comorbidities. The role of serum total bilirubin and direct bilirubin in prognosis of covid-19 be studied further to evaluate more mechanistic explanation.