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.