Questionable accuracy of home blood pressure measurements in the obese population – Validation of the Microlife WatchBP O3^® and Omron RS6^® devices according to the European Society of Hypertension-International Protocol

Figures & data

Figure 1 Plots of systolic (A) and diastolic (B) BP differences between the Microlife WatchBP O3^® and the mean of two observer readings in 34 subjects (n=102).

Notes: Delta SBP (device − reference): systolic difference between the Microlife and the mercury; mean SBP device and reference: mean systolic average values of the Microlife and the mercury sphygmomanometer. Delta DBP (device − reference): diastolic difference between the Microlife and the mercury; mean DBP device and reference: mean diastolic average values of the Microlife and the mercury sphygmomanometer.
Abbreviations: BP, blood pressure; DBP, diastolic blood pressure; SBP, systolic blood pressure.

Table 1 Validation results for Microlife WatchBP O3^® according to the ESH-IP 2010

Validation results – Microlife WatchBP O3
Part 1	≤5 mmHg	≤10 mmHg	≤15 mmHg	Grade 1	Mean mmHg	SD mmHg
Pass requirements
Two of	73	87	96
All of	65	81	93
Achieved
SBP	64	86	94	Fail	0.3	7.8
DBP	62	93	101	Fail	−1.9	6.4
Part 2	2/3≤5 mmHg	0/3≤5 mmHg		Grade 2		Grade 3
Pass requirements	≥24	≤3
Achieved
SBP	22	6		Fail		Fail
DBP	20	6		Fail		Fail
Part 3						Result
						Fail

Notes: Accuracy is determined by the number differences in these ranges both for individual measurements (Part 1) and for individual subjects (Part 2). To pass, a device must achieve all the minimum pass requirements shown.

Abbreviations: DBP, diastolic blood pressure; ESH, European Society of Hypertension; IP, International Protocol; SBP, systolic blood pressure; SD, standard deviation.

Figure 2 Plots of systolic (A) and diastolic (B) BP differences between the Omron RS6^® and the mean of two observer readings in 34 subjects (n=102).

Notes: Delta SBP (device − reference): systolic difference between the Omron RS6 and the mercury sphygmomanometer; mean SBP device and reference: mean systolic average values of the Omron RS6 and the mercury sphygmomanometer. Delta DBP (device − reference): diastolic difference between the Omron RS6 and the mercury; mean DBP device and reference: mean diastolic average values of the Omron RS6 and the mercury sphygmomanometer.
Abbreviations: BP, blood pressure; DBP, diastolic blood pressure; SBP, systolic blood pressure.

Table 2 Validation results for Omron RS6^® according to the ESH-IP 2010

Validation results – Omron RS6
Part 1	≤5 mmHg	≤10 mmHg	≤15 mmHg	Grade 1	Mean mmHg	SD mmHg
Pass requirements
Two of	73	87	96
All of	65	81	93
Achieved
SBP	42	75	89	Fail	2.7	9.9
DBP	42	69	87	Fail	3.5	11.1
Part 2	2/3≤5 mmHg	0/3≤5 mmHg		Grade 2		Grade 3
Pass requirements	≥24	≤3
Achieved
SBP	13	10		Fail		Fail
DBP	13	12		Fail		Fail
Part 3						Result
						Fail

Notes: Accuracy is determined by the number differences in these ranges both for individual measurements (Part 1) and for individual subjects (Part 2). To pass, a device must achieve all the minimum pass requirements shown.

Abbreviations: DBP, diastolic blood pressure; ESH, European Society of Hypertension; IP, International Protocol; SBP, systolic blood pressure; SD, standard deviation.

Figure 3 Correlation between the differences in DBP measured by Microlife WatchBP O3^® device and the mercury sphygmomanometer and the mean average of DBP values in the total population (34 participants). “r”, Pearson’s correlation coefficient; p value is considered statistically significant when p<0.05.

Abbreviation: DBP, diastolic blood pressure.