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.

Objective: Two oscillometric devices, the Microlife WatchBP O3 and the Omron RS6, designed for self-blood pressure measurement were evaluated according to the European Society of Hypertension (ESH)-International Protocol (IP) Revision 2010 in the obese population.

Methods: The Microlife WatchBP O3 measures blood pressure (BP) at the brachial level and the Omron RS6 measures BP at the wrist level. The ESH-IP revision 2010 includes a total of 33 subjects. The difference between observers' and device BP values was calculated for each measure. A total of 99 pairs of BP differences were classified into three categories (≤5, ≤10, and ≤15 mmHg). The protocol procedures were followed precisely in each of the two studies.

Results: Microlife WatchBP O3 and Omron RS6 failed to fulfill the criteria of the ESH-IP. The mean differences between the device and the mercury readings were: 0.3±7.8 mmHg and -1.9±6.4 mmHg for systolic BP and diastolic BP, respectively, for Microlife WatchBP O3, and 2.7±9.9 mmHg for SBP and 3.5±11.1 mmHg for diastolic BP for Omron RS6.

Conclusion: Microlife WatchBP O3 and Omron RS6 readings differing from the mercury standard by more than 5, 10, and 15 mmHg failed to fulfill the ESH-IP revision 2010 requirements in obese subjects. Therefore, the two devices cannot be recommended for use in obese subjects.