Clinical Evaluation of the Measurement Performance of the Philips Health Watch: A Within-Person Comparative Study

Figure 1. The Philips health watch with companion app running on a mobile phone.

Figure 2. Boxplot (left-hand panel) of the ratio of cumulative total energy expenditure (TEE) between the Philips health watch (HW) and the K4b2 (K4) reference. The thick black line indicates the mean of the data, the red dashed lines the predefined ±15% equivalence interval, and the other thin black lines represent the calculated 95% CI of equivalence. Right-hand panel: Bland-Altman plot of the cumulative TEE for the HW and the reference. The solid black line indicates the average bias and the dashed black lines represent the 95% limits of agreement. Symbols represent participants’ individual data as indicated in the legend and are the same for both panels.

Figure 3. Boxplot (left-hand panel) of the ratio of resting heart rate (RHR) determined from the Philips health watch (HW) data during the rest protocol in the laboratory to the RHR determined from the Actiwave data during the rest protocol in the laboratory. The thick black line indicates the mean of the data, the red dashed lines the predefined equivalence interval, and the other black lines the calculated 95% CI of equivalence. Right-hand panel: Bland-Altman plot of the RHR from the HW and reference. The solid black line indicates the average bias and the dashed black lines represent the 95% limits of agreement. Symbols represent participants as indicated in the legend and are the same for both panels. bpm: beats per minute.

Figure 4. Example of free-living heart rate (HR), resting heart rate, and total energy expenditure (TEE) for participant P120. Top: Philips health watch HR as a function of time for the free-living portion of the trial (black) and the resting heart rate from the health watch (green dashed line; note that resting heart rate requires a 24-hour assessment and therefore day 1 does not have a resting heart rate value). Bottom: TEE as a function of time for the free-living portion of the trial. bpm: beats per minute.

Figure 5. Boxplot (left-hand panel) of estimated step count as ratio between the health watch (HW) and the waist-worn reference (Fitbit One, FB), for all walk activities combined. The thick black line indicates the mean of the data, the red dashed lines the predefined equivalence interval, and the other black lines the calculated 95% CI of equivalence. Right-hand panel: Bland-Altman plot of the estimated step count of the HW and the reference measurement. The solid black line indicates the average bias and the dashed black lines represent the 95% limits of agreement. Symbols represent participants as indicated in the legend, and the legend is the same for both panels.

Figure 6. Boxplot (left-hand panel) of the ratio of estimated respiration rate (RR) from the health watch (HW) and the K4b2 (K4) reference, during rest. The thick black line indicates the mean of the data, the red dashed lines the predefined equivalence interval, and the other black lines the calculated 95% CI of equivalence. Right-hand panel: Bland-Altman plot of the estimated RR from the HW and from the reference measurement. The solid black line indicates the average bias and the dashed black lines represent the 95% limits of agreement. Symbols represent participants as indicated in the legend; the legend is the same for both panels.