Accuracy of Smartwatch Pulse Oximetry Measurements in Hospitalized Patients With Coronavirus Disease 2019

Abstract

ObjectiveTo assess the ability of two commercially available smartwatches to accurately detect clinically significant hypoxia in patients hospitalized with COVID-19. Patients and MethodsA prospective multi-center validation study was performed from 1st November 2021 to 31st August 2022 assessing the Apple Watch Series 7 and Withings ScanWatch inbuilt pulse oximetry, against simultaneous ward-based oximetry as the reference standard. Patients hospitalized with active COVID-19 infection not requiring intensive care admission were recruited. Results750 smartwatch pulse oximetry measurements and 400 ward oximetry readings were successfully obtained from 200 patients (male 54%, age 66 ± 18 years). For detection of clinically significant hypoxia the Apple Watch had a sensitivity and specificity of 34.8% and 97.5% respectively, with a positive predictive value (PPV) of 78.1% and negative predictive value (NPV) of 85.6%. The Withings ScanWatch had a sensitivity and specificity of 68.5% and 80.8% respectively with a PPV of 44.7% and NPV of 91.9%. Overall accuracy was 84.9% for the Apple Watch and 78.5% for the Withings ScanWatch. Spearman rank correlation coefficients demonstrated moderate correlation to ward-based PPG (Apple: rs = 0.61; Withings: rs = 0.51, both p < 0.01). ConclusionWhile smartwatches are able to provide SpO2 readings, their overall accuracy may not be sufficient to replace standard PPG technology in detecting hypoxia in COVID-19 patients.