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- Published on: 8 January 2021
- Published on: 8 January 2021The Prognostic Value of the Quick Walk Test during COVID-19 Outbreaks: the Experience of the Fenice Network
We read with great interest the study by Goodacre et al. [1], where post-exertion oxygen saturation adds modest prognostic information to clinical assessment of suspected COVID-19 in the ED.
This is partially in contrast with the findings of our study [2], performed within the Fenice Network (Italian group for clinical research in Emergency Medicine). In consecutive ED patients with SpO2 ≥ 95%, the most promising version of a standardised quick walk test (QWT) yielded a sensitivity of 83.3% (95% confidence interval [CI] = 35.9% to 99.6%), and specificity of 93.4% (95% CI = 91.5% to 95.0%). The positive and negative predictive values (PPVs and NPVs) were 8.6% (95% CI = 2.9% to 19.0%) and 99.9% (95% CI = 99.3% to 100.0%).
This difference is probably due to 3 factors:
1. The test standardisation. In our case series, the test was standardised for all centres and consists of a 30-40 metres walk at the maximun possible speed for each patient. Conversely, in the study by Goodacre et al., exertion SpO2 was either recorded after different, not standardised, intentional tests or could have made opportunistically after a spontaneous patient’s effort. The latter condition is particularly worrisome for the purpose of a thorough assessment of the prognostic value of the post-exertion oxygen saturation.
2. The outcome definition. Goodacre et al. considered patients who died or required respiratory, cardiovascular or renal support within 30 days after initial p...
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None declared.