TY - JOUR T1 - Post-exertion oxygen saturation as a prognostic factor for adverse outcome in patients attending the emergency department with suspected COVID-19: a substudy of the PRIEST observational cohort study JF - Emergency Medicine Journal JO - Emerg Med J SP - 88 LP - 93 DO - 10.1136/emermed-2020-210528 VL - 38 IS - 2 AU - Steve Goodacre AU - Ben Thomas AU - Ellen Lee AU - Laura Sutton AU - Amanda Loban AU - Simon Waterhouse AU - Richard Simmonds AU - Katie Biggs AU - Carl Marincowitz AU - José Schutter AU - Sarah Connelly AU - Elena Sheldon AU - Jamie Hall AU - Emma Young AU - Andrew Bentley AU - Kirsty Challen AU - Chris Fitzsimmons AU - Tim Harris AU - Fiona Lecky AU - Andrew Lee AU - Ian Maconochie AU - Darren Walter Y1 - 2021/02/01 UR - http://emj.bmj.com/content/38/2/88.abstract N2 - Background Measurement of post-exertion oxygen saturation has been proposed to assess illness severity in suspected COVID-19 infection. We aimed to determine the accuracy of post-exertional oxygen saturation for predicting adverse outcome in suspected COVID-19.Methods We undertook a substudy of an observational cohort study across 70 emergency departments during the first wave of the COVID-19 pandemic in the UK. We collected data prospectively, using a standardised assessment form, and retrospectively, using hospital records, from patients with suspected COVID-19, and reviewed hospital records at 30 days for adverse outcome (death or receiving organ support). Patients with post-exertion oxygen saturation recorded were selected for this analysis. We constructed receiver-operating characteristic curves, calculated diagnostic parameters, and developed a multivariable model for predicting adverse outcome.Results We analysed data from 817 patients with post-exertion oxygen saturation recorded after excluding 54 in whom measurement appeared unfeasible. The c-statistic for post-exertion change in oxygen saturation was 0.589 (95% CI 0.465 to 0.713), and the positive and negative likelihood ratios of a 3% or more desaturation were, respectively, 1.78 (1.25 to 2.53) and 0.67 (0.46 to 0.98). Multivariable analysis showed that post-exertion oxygen saturation was not a significant predictor of adverse outcome when baseline clinical assessment was taken into account (p=0.368). Secondary analysis excluding patients in whom post-exertion measurement appeared inappropriate resulted in a c-statistic of 0.699 (0.581 to 0.817), likelihood ratios of 1.98 (1.26 to 3.10) and 0.61 (0.35 to 1.07), and some evidence of additional prognostic value on multivariable analysis (p=0.019).Conclusions Post-exertion oxygen saturation provides modest prognostic information in the assessment of selected patients attending the emergency department with suspected COVID-19.Trial registration number ISRCTN Registry (ISRCTN56149622) http://www.isrctn.com/ISRCTN28342533. ER -