933 ASSESSMENT OF NON-INVASIVE MEASUREMENTS OF OXYGEN SATURATION AND HEART RATE WITH AN APPLE SMARTWATCH: COMPARISON WITH A STANDARD PULSE OXIMETER

Abstract

Abstract Background The most commonly used method to assess peripheral oxygen saturation (SpO2) in clinical practice is pulse oximetry. Smartwatches are widespread and are increasingly being used for digital health information. The smartwatch Apple Watch 6 was developed with a new sensor and an app that allows taking on-demand readings of blood oxygen and background readings, day and night. Aims The primary aim of the study was the head-to-head comparison of the measurements of SpO2 and heart rate (HR) by the smartwatch and the standard pulse oximeter. The secondary aim was the comparison of the measurements of SpO2 and HR between subgroups (lung disease, cardiovascular disease, healthy subjects). Methods and results We enrolled study participants with lung or cardiovascular disease and healthy subjects. A total of 265 subjects were screened for enrollment in this study. After screening, 257 subjects were included in the present study. The measurements of SpO2 and HR were obtained with the Apple Watch 6 and the Nellcor system and taken within 1 minute of each other in order to ensure comparability between the two devices. The correlation between the two technologies was assessed using linear regression and estimated with Pearson analysis for normally distributed data and Spearman analysis for nonparametric data. A plot of the differences between techniques was created according to the method described by J.M. Bland and D.G. Altmann. We observed a strong positive correlation between the smartwatch and the standard commercial device in the evaluation of SpO2 measurements (r=0.89, p< 0.0001; Figure 1A) and HR measurements (r=0.98, p< 0.0001; Figure 1B). A very good concordance was found between SpO2 (bias, -0.2289; SD, 1.66; lower limit, -3.49; and upper limit, 3.04; Figure 2A) and HR (bias, -0.1052; SD, 2.93; lower limit, -5.84; and upper limit, 5.63; Figure 2B) measured by the smartwatch in comparison with the standard commercial device using Bland–Altman analysis. We observed similar agreements and concordance even in the different subgroups. Conclusions In conclusion, our study demonstrates the feasibility and agreement of the Apple Watch 6 compared with the standard device used to assess SpO2 in patients with cardiovascular or lung diseases and in healthy subjects.