The Effect of the Time of Favipiravir Initiation on Clinical Course and Mortality among COVID-19 Patients in the Intensive Care Unit

Favipiravir Timing and Clinical Outcomes in COVID-19

Abstract

Background: Coronavirus disease 2019 (COVID-19) may lead to severe viral pneumonia and acute respiratory failure requiring intensive care unit (ICU) admission. During the early phase of the pandemic, favipiravir was widely used as an antiviral agent; however, evidence regarding the optimal timing of its initiation in critically ill patients has remained limited. This study aimed to evaluate the effect of favipiravir initiation timing on clinical outcomes and mortality in ICU patients with COVID-19.

Material and Methods: This retrospective cohort study included adult patients (≥18 years) with laboratory-confirmed COVID-19 who were admitted to the ICU between April 1 and June 1, 2020. Patients were divided into two groups according to the timing of favipiravir initiation: Group I, favipiravir initiated at ICU admission; and Group II, favipiravir initiated prior to ICU admission and continued during the ICU stay. Demographic characteristics, comorbidities, clinical outcomes, laboratory parameters, and treatment-related data were obtained from electronic medical records and ICU follow-up charts. The primary outcomes were ICU length of stay and mortality. Secondary outcomes included respiratory support requirements and corticosteroid use.

Results: A total of 158 patients were analyzed (Group I, n=76; Group II, n=82). Baseline demographic and clinical characteristics were comparable between the groups. The ICU length of stay was significantly shorter in Group II compared with Group I (6.57 ± 5 vs. 10.91 ± 8.54 days, p=0.001). Corticosteroid therapy was required more frequently in Group I than in Group II (36.8% vs. 15.8%, p=0.003). Rates of intubation, noninvasive mechanical ventilation, high-flow nasal cannula use, and tocilizumab therapy did not differ significantly between the groups. Mortality was numerically lower in Group II, but this difference was not statistically significant (46% vs. 56.6%, p=0.148). Laboratory parameters, including d-dimer, ferritin, and C-reactive protein, were similar between the groups.     

Conclusion: Earlier initiation of favipiravir prior to ICU admission was associated with a shorter ICU stay and reduced corticosteroid requirement but did not significantly affect mortality. These findings suggest that early antiviral therapy may modestly influence clinical progression in critically ill COVID-19 patients without altering overall survival.