Background. Presently, data on effectiveness of triple combination of favipiravir, chloroquine-based agents and protease inhibitors for treatment of covid-19 patients with pulmonary involvements is limited.
Method. We conducted a retrospective observational study of hospitalized adult COVID-19 patients at five tertiary care hospitals in Thailand.
Results. Among 247 COVID-19 patients, 63 patients met the study criteria for pulmonary involvements and were prescribed favipiravir according to the Thai National guidelines. Nearly all (61/63,96.8%) were concomitantly treated with chloroquine-based agent and protease inhibitors. The median baseline NEWS2 score was 5 (0–16) and four patients (4/63,6.4%) required invasive mechanical ventilation upon hospitalization. The Day-7 clinical improvement rate [95%CI] was 66.7%[53.7–78.0%] in all patients, 92.5%[75.7%–99.1%] in patients who did not require O2-supplementation, and 47.2%[0.4%–64.5%] in patients who required O2-supplementation. No life-threatening adverse events were identified. The 28-day mortality rate was 4.8%. Multivariate analysis revealed three poor prognostic factors for Day-7 clinical improvement [odds ratio (95%CI);p-value]: older age [0.94(0.89–0.99);p=0.04], higher baseline NEWS2 score [0.64(0.47–0.88);p=0.006], and lower favipiravir loading dose (≤45 mg/kg/day) [0.04 (0.005–0.4);p=0.006].
Conclusion. Our study preliminary reports the acceptable effectiveness of triple combination regimen for treating COVID-19 patients. In addition to older age and a high baseline NEWS2 score, a low loading dose of favipiravir (≤45 mg/kg/day) was also identified as a poor prognostic factor for early clinical improvement. Further studies with the control group to confirm the effectiveness of triple combination and optimal dose of favipiravir should be performed.