Effect of Tocilizumab Treatment on Patients with Coronavirus Disease 2019 and Bacteremia: A Retrospective Cohort Study.

Introduction: This study aimed to determine if tocilizumab treatment for coronavirus disease 2019 (COVID-19) increases bacteremia and suppresses fever and inflammatory reactants.

Methods: In this single-center, retrospective, observational study, all patients with COVID-19 admitted to our emergency intensive care unit from March 2020 to August 2021 were categorized into tocilizumab-treated and tocilizumab-naïve groups, and the incidence of bacteremia and other factors between the two groups were compared. Patients with bacteremia were further classified into tocilizumab-treated and tocilizumab-naïve groups to determine if fever and inflammatory reactants were suppressed.

Results: Overall, 144 patients were included in the study, 51 of whom received tocilizumab, which was administered on the day of admission. Further, of the 24 (16.7%) patients with bacteremia, 13 were in the tocilizumab-treated group. Results revealed a significant difference in the C-reactive protein level (p < 0.001) at the onset of bacteremia between the tocilizumab-treated group [median 0.42 mg/dL (0.27-0.44 mg/dL)] and the tocilizumab-naïve group [7.48 mg/dL (4.56-13.9 mg/dL)]. The median number of days from admission to onset of bacteremia was not significantly different between the tocilizumab-treated group [10 days (9-12 days)] and the tocilizumab-naïve group [9 days (7.5-11 days)] (p = 0.48). There was no significant difference in fever between the groups. Multivariate logistic analysis showed that tocilizumab treatment did not affect the probability of bacteremia.

Conclusion: Treatment of patients with COVID-19 with tocilizumab does not increase the risk of bacteremia. Tocilizumab suppresses C-reactive protein levels but not fever. Therefore, careful monitoring of fever can reduce the risk of missed bacteremia.