Analysis of oxygen blood saturation/respiratory rate index, news2, curb65, and quick sequential organ failure assessment scores to assess prognosis in patients with mild coronavirus disease 2019

Background: Hospital bed saturation has been one of the problems to solve during the SARS-CoV-2 pandemic. However, not every patient who is admitted requires close monitoring or specific therapeutics. Mild cases could be managed in the outpatient setting. Objective: Our study aimed to analyze the accuracy of the oxygen saturation/respiratory rate (sat/RR) index, NEWS2, CURB65, and quick Sequential Organ Failure Assessment (qSOFA) scores to predict supplemental oxygen requirement and prolonged hospital stay in patients with mild coronavirus disease 2019 (COVID-19). Methods: A prospective cohort study in an academic medical center. We compared the values of these scores according to the occurrence or not of each outcome. When differences between groups were statistically significant, the discriminatory capacity of the score for that outcome was analyzed. Results: We included 271 patients. Of them, 11.07% required supplemental oxygen, showing significantly higher values of NEWS2 score and qSOFA score, and lower values of Sat/RR index. About 38% presented prolonged hospital stay, with significantly higher values of NEWS2 score and lower values of sat/RR index. The ROC curve area under the curve (AUC) of sat/RR index to discriminate the requirement of supplemental oxygen was 0.72 (CI 95% 0.61-0.84). The ROC curve of NEWS2 and qSOFA for the same outcome was 0.75 (95% [95% CI 0.65-0.85]) and 0.66 (95% CI 0.57-0.76), respectively. The ability of the Sat/RR index to discriminate the requirement of prolonged hospitalization showed an AUC of 0.67 (95% [95% CI 0.60-0.73]). The NEWS2 score showed an AUC of 0.63 (CI 95% 0.56-0.70) for the same outcome. Conclusions: sat/RR index and NEWS2 score have a good capacity to discriminate patients at risk of clinical worsening, being the Sat/RR index simpler and easier to calculate.