Clinical outcomes by supplemental oxygen use in remdesivir-treated, hospitalised adults with COVID-19

•Real-world study of hospitalised COVID-19 patients treated with remdesivir.•Higher mortality and longer hospitalisation in HFO compared to LFO and NSO groups.•Early initiation (upon admission) of remdesivir has mortality benefit.•Remdesivir use and outcomes differed by country. Clinical trials show different effects of remdesivir on clinical outcomes relative to COVID-19 severity at hospital admission; in Europe, there are few real-world data. A multicentre, multinational retrospective cohort study in adult patients hospitalised with PCR-confirmed COVID-19 was conducted to understand remdesivir clinical use in different countries and to describe outcomes for patients receiving remdesivir stratified by oxygen use. Primary endpoints were all-cause mortality at day 28 and hospitalisation duration. Patients were categorised by baseline disease severity: no supplemental oxygen (NSO); low flow oxygen ≤ 6 litres (l)/minute (LFO); high flow oxygen > 6 l/minute (HFO). Four hundred and forty-eight (448) patients (72 [16.1%] HFO; 295 [65.8%] LFO; 81 (18.1%] NSO) were included; median age was 65 years and 64% were male. Mortality was higher in patients on HFO (rate 23.6%) compared to LFO (10.2%; p = 0.001) or NSO (6.2%; p = 0.002). Duration of hospitalisation was longer in patients on HFO (13 days) compared to LFO (9 days; p = 0.003) and NSO (9 days; p = 0.021). Patients who initiated remdesivir ≥ 2 days compared to within a day of hospitalisation had a 4.2 times higher risk of death, irrespective of age, sex, comorbidities, and oxygen support at baseline. Requirement for mechanical ventilation/ECMO and readmission within 28 days of discharge was similar across groups. Remdesivir use and outcomes differed by country. A higher mortality rate and duration of hospitalisation was seen in remdesivir-treated COVID-19 patients on HFO compared to LFO and NSO. Initiation of remdesivir upon admission as opposed to delayed initiation has a mortality benefit. Clinical Trials Registration: NCT04847622.