Abstract
Objectives: The majority of patients with mild-to-moderate COVID-19 can be managed using virtual care. Dyspnoea is challenging to assess remotely, and the accuracy of subjective dyspnoea measures in capturing hypoxaemia have not been formally evaluated for COVID-19. We explored the accuracy of subjective dyspnoea in diagnosing hypoxaemia in COVID-19 patients.
Methods: This is a retrospective cohort study of consecutive outpatients with COVID-19 who met criteria for home oxygen saturation monitoring at a university-affiliated acute care hospital in Toronto, Canada from 3 April 2020 to 13 September 2020. Dyspnoea measures were treated as diagnostic tests, and we determined their sensitivity (SN), specificity (SP), negative/positive predictive value (NPV/PPV) and positive/negative likelihood ratios (+LR/-LR) for detecting hypoxaemia. In the primary analysis, hypoxaemia was defined by oxygen saturation <95%; the diagnostic accuracy of subjective dyspnoea was also assessed across a range of oxygen saturation cutoffs from 92% to 97%.
Results: During the study period, 89/501 (17.8%) of patients met criteria for home oxygen saturation monitoring, and of these 17/89 (19.1%) were diagnosed with hypoxaemia. The presence/absence of dyspnoea had limited accuracy for diagnosing hypoxaemia, with SN 47% (95% CI 24% to 72%), SP 80% (95% CI 68% to 88%), NPV 86% (95% CI 75% to 93%), PPV 36% (95% CI 18% to 59%), +LR 2.4 (95% CI 1.2 to 4.7) and -LR 0.7 (95% CI 0.4 to 1.1). The SN of dyspnoea was 50% (95% CI 19% to 81%) when a cut-off of < 92% was used to define hypoxaemia. A modified Medical Research Council dyspnoea score >1 (SP 98%, 95% CI 88% to 100%), Roth maximal count <12 (SP 100%, 95% CI 75% to 100%) and Roth counting time <8 s (SP 93%, 95% CI 66% to 100%) had high SP that could be used to rule in hypoxaemia, but displayed low SN (≤50%).
Conclusions: Subjective dyspnoea measures have inadequate accuracy for ruling out hypoxaemia in high-risk patients with COVID-19. Safe home management of patients with COVID-19 should incorporate home oxygenation saturation monitoring.
Keywords: COVID-19; infectious diseases; public health.
【저자키워드】 COVID-19, public health, Infectious diseases, 【초록키워드】 public health, Infectious diseases, hospital, diagnostic, oxygen, Predictive value, oxygen saturation, sensitivity, specificity, Diagnostic accuracy, Accuracy, diagnostic tests, management, Patient, Virtual care, hypoxaemia, Canada, Care, COVID-19 patients, High-risk patients, Dyspnoea, Outpatient, Mild-to-moderate, Oxygenation, criteria, Predictive, Medical Research Council, retrospective cohort study, 95% CI, study period, measure, Cutoff, primary analysis, likelihood ratio, Toronto, cut-off, diagnosing, high-risk patient, defined, was used, diagnosed, evaluated, treated, majority, to define, NPV, patients with COVID-19, PPV, Subjective, with COVID-19, 【제목키워드】 Outpatient,