Continuously available ratio of SpO(2)/FiO(2) serves as a noninvasive prognostic marker for intensive care patients with COVID-19

Lu, Xiaofan; Jiang, Liyun; Chen, Taige; Wang, Yang; Zhang, Bing; Hong, Yizhou; Wang, Jun; Yan, Fangrong

RATIONALE: Oxygen saturation to fraction of inspired oxygen ratio (SpO(2)/FiO(2)) has been described as potential predictor of poor outcome for COVID-19, without considering its time-varying behavior though. METHODS: Prognostic value of SpO(2)/FiO(2) was evaluated by jointly modeling the longitudinal responses of SpO(2)/FiO(2) and time-to-event data retrieved from 280 severe and critically ill (intensive care) patients with COVID-19. RESULTS: A sharply decrease of SpO(2)/FiO(2) from the first to second measurement for non-survivors was observed, and a strong association between square root SpO(2)/FiO(2) and mortality risk was demonstrated, with a unit decrease in the marker corresponding to 1.82-fold increase in mortality risk (95% CI: 1.56–2.13). CONCLUSIONS: The current study suggested that SpO(2)/FiO(2) could serve as a non-invasive prognostic marker to facilitate early adjustment for treatment, thus improving overall survival.