Remdesivir versus Favipiravir in Hospitalized Patients with Moderate to Severe COVID-19 Pneumonia: A Propensity Score-Matched Retrospective Cohort Study.

Background: Remdesivir treatment was associated with a reduced 28-day mortality and recovery time among patients hospitalized with severe COVID-19. Favipiravir is broadly used to treat COVID-19. However, various studies have had conflicting results on the efficacy of favipiravir for COVID-19. We hypothesized that remdesivir is more effective in clinical outcomes regarding the 29-day mortality rates, length of stay, and recovery rate than favipiravir in patients with moderate to severe COVID-19 pneumonia.

Methods: We performed a retrospective cohort study that included adult hospitalized COVID-19 pneumonia patients with hypoxemia. Patients were classified into two groups according to the antiviral drugs. Age, oxygen saturation, fraction of inspired oxygen, and Charlson comorbidity index were used for propensity score matching. The primary objective was to determine whether the type of antiviral agent is associated with 29-day mortality. Other outcomes were the 15-day recovery rate and the length of intensive care unit or hospital stay.

Results: A total of 249 patients with moderate to severe COVID-19 pneumonia were included. With an adjustment for propensity score-matched, there were 204 patients for further analysis (102 patients in each antiviral drug group). Remdesivir patients had higher Radiographic Assessment of Lung Edema (RALE) scores on Chest X-ray (14.32±9.08 vs 11.34±8.46; standardized mean difference =33.9%). The Charlson Comorbidity Index Scores were comparable. The prevalences of diabetes, obesity, hypertension, and non-HIV immunocompromised state were higher in the remdesivir group. Regarding the primary outcomes, after adjusting by diabetes, obesity, and RALE score, there was no difference in the 29-day mortality rate between both groups [26 patients (25.5%) in the remdesivir group vs 28 patients (27.5%) in the favipiravir group]. The Kaplan-Meier curve analysis at 29 days indicated no significant difference in cumulative survival rate. The two groups' adjusted hazard ratio was 0.72; 95% CI, 0.41 to 1.25, =0.24. A Kaplan-Meier analysis on the 15-day cumulative survival rate observed a trend towards a higher survival rate in the remdesivir group (adjusted hazard ratio 0.41; 95% CI, 0.20 to 0.84; p= 0.02) The proportion of patients who recovered on day 15, the length of intensive care unit(ICU) stays, and the hospital stay were not different between remdesivir and favipiravir groups (62 patients (60.8%) vs 56 patients (54.9%), p=0.39; 11.48 ± 11.88 days vs 10.87 ± 9.31 days, =0.69; and 16.64±14.28 days vs 16.59 ±11.31 days, =0.98, respectively).

Conclusion: In patients with moderate to severe COVID-19 pneumonia, Remdesivir did not demonstrate superior benefits over Favipiravir regarding 29-day mortality, 15-day recovery rates, or hospital and ICU stay lengths. However, further investigation into the 15-day cumulative survival rate revealed a trend towards improved survival in the Remdesivir group.