Objectives: To compare home blood pressure (BP) values obtained with two validated OMRON (wrist or arm) monitors used in the same individual sequentially, but with two different hand positions.
Methods: In 200 hypertensive individuals referred to hypertension specialists, a self-measurement of BP was performed sequentially with an OMRON M4-I (arm cuff, A/A, British Hypertention Society validation) and an OMRON RX-I (wrist cuff, B/B, BHS validation). Each patient recorded home BP during two periods of 4 days with three measures in the morning and three in the evening. Order for use of each monitor was randomized. For the first 100 patients, the hand was positioned on the opposite shoulder whereas for the next 100 patients, the hand was positioned on the opposite elbow. BP values were reported on a standardized document.
Results: In this population, aged 60±10 years, with 54% of men, BP values were 136±/80± mmHg with the wrist monitor (WM) when the hand is positioned on the opposite shoulder as compared with 144±16/81±9 mmHg obtained with the arm monitor taken as the gold standard. On the contrary, BP values were 142±/82± mmHg with the WM when the hand is positioned on the opposite elbow as compared with 144±16/81±9 mmHg obtained with the arm monitor. The lower value of systolic blood pressure observed with WM positioned on the shoulder is independent of age, initial BP level and order of use (multivariate analysis).
Conclusion: When advising home BP monitoring with a WM, the instruction to be given to patients is to position the hand on the opposite elbow.