A propensity score matching analysis for CPAP versus conventional oxygen therapy as a ceiling of care in COVID-19-associated type 1 respiratory failure

Abstract

Background Continuous positive airway pressure (CPAP) is increasingly used as a ward ceiling of care. Nevertheless, little is known about its effectiveness. Objective A retrospective study to explore whether CPAP therapy as a ceiling of care improves outcome in coronavirus disease 2019 (COVID-19)-infected patients with acute respiratory failure. Methods A retrospective cohort study was conducted on adult COVID-19-infected patients admitted to two UK hospitals from the March 1 to June 30, 2020. All patients experienced type 1 respiratory failure and were not suitable for intubation. They were divided into two groups: patients for CPAP versus conventional oxygen therapy (COT). Results A total of 39 patients received CPAP, whereas 247 received COT. CPAP group patients were more hypoxic (mean SpO2 86.5% vs. 91%, P=0.003), younger (mean±SD: 71.8±8.8 vs. 80.7±9.8 years, P<0.001), and less frail than the COT group [median (interquartile range) clinical frailty score 4 (3–5) vs. 6 (4–7), P<0.001]. Overall, 35 patients died in the CPAP group (89.7%) compared with 185 patients in the COT group (74.9%) (P=0.041). Propensity score matching of the two groups showed that CPAP was still associated with higher mortality (90.3 vs. 67.7%, P=0.029). Length of hospital stay was similar in both groups (mean±SD 9.2±7.3 vs. 9.7±8.6 days, P=0.719). Conclusion In COVID-19-infected patients presenting with type 1 respiratory failure and deemed not suitable for escalation to intubation, the use of CPAP therapy does not carry extra benefit than COT. In such patients, COT appears to be the appropriate measure. Further studies are required to corroborate these findings.