Validation of Two Automatic Devices for Self-measurement of Blood Pressure According to the International Protocol of the European Society of Hypertension: the Omron M6 (HEM-7001-E) and the Omron R7 (HEM 637-IT)

Background: Two electronic devices for self-measurement of blood pressure - a brachial monitor, the Omron M6, and a wrist monitor, the Omron R7 - were evaluated in two separate studies according to the International Protocol of the European Society of Hypertension.

Design: The International Validation Protocol is divided into two phases: the first phase is performed on 15 selected participants (45 pairs of blood pressure measurements); if the device passes this phase, 18 supplementary participants are included (54 pairs of blood pressure measurements) making a total number of 33 participants (99 pairs of blood pressure measurements) on whom the final validation is performed.

Methods: The same methodology recommended by the European Society of Hypertension protocol was applied for both studies. In each study and for each participant, four blood pressure measurements were taken simultaneously by two trained observers using mercury sphygmomanometers alternately with three measurements taken by the tested device. The difference between the blood pressure value given by the device and that obtained by the two observers (mean of the two observers) was calculated for each measure. The 99 pairs of blood pressure differences were classified into three categories (<or=5, <or=10 and <or=15 mmHg). The number of differences in each category was compared with the number required by the International Protocol. An individual analysis was then done to determine the number of comparisons <or=5 mmHg for each participant. At least 22 of the 33 participants should have two of their three comparisons <or=5 mmHg.

Results: In both studies, the two tested devices passed the first and the second phases of the validation process. The average differences between the device and mercury sphygmomanometer readings were 0.8+/-2.7 and -1.9+/-3.3 mmHg for systolic and diastolic blood pressure, respectively, for the Omron M6 device, and 0.2+/-4.2 and 0.2+/-2.9 mmHg for systolic and diastolic blood pressure, respectively, for the Omron R7 device. For both devices, readings differing by less than 5, 10 and 15 mmHg for systolic and diastolic blood pressure values fulfill the recommendation criteria of the International Protocol as well as the individual analysis.

Conclusions: The Omron M6 (HEM-7001-E) and the Omron R7 (HEM 637-IT) devices fulfilled the validation recommendations of the International Protocol.