[Systolic blood pressures are not comparable when home blood pressure is measured with a wrist or an arm validated monitor]

Abstract

Objectives: To compare home blood pressure values obtained with two validated OMRON (wrist or arm) monitors used sequentially in the same subject.

Methods: In 265 hypertensive subjects referred to hypertension specialists, a self measurement of blood pressure was performed sequentially with an OMRON M4-I (arm cuff, A/A, BHS validation) or OMRON RX-I (wrist cuff, B/B, BHS validation). Each patient recorded home blood pressure during two periods of 4 days with 3 measures in the morning and 3 in the evening. Order for use of each monitor was randomised. With wrist devices, subjects were advised to keep the arm at heart level during measurements. BP values were reported on a standardized document. Patients were asked by a questionnaire about the tolerance and feasibility of the 2 methods.

Results: In this population, aged 59 +/- 14 years, with 60% of men and a mean blood pressure of 152 +/- 21 / 86 +/- 14 mmHg, the home blood pressure values were 143 +/- 20/81 +/- 11 mmHg with the arm monitor and 135 +/- 10 / 80 +/- 11 mmHg with the wrist monitor. Mean SBP adjusted on age, initial blood pressure level and period order was significantly lower when home blood pressure monitoring has been recorded with a wrist monitor as compared to an arm monitor (p < 0.001). Self measurement of blood pressure was felt as easy in 92% with the arm monitor and in 96% with the wrist monitor (p < 0.05). Self measurement of blood pressure was felt as constraining in 14% with the arm monitor and in 7% with the wrist monitor (p < 0.01). The feasibility between the two devices was good with none of the value missing in 86% with the arm monitor and in 85% with the wrist monitor. The missing values were in 56% the fourth day.

Conclusion: Despite the use of two validated monitors, mean SBP is significantly lower when home blood pressure monitoring is recorded with a wrist monitor as compared to an arm monitor. Uncertainty in the arm position with the use of wrist device could explain these results. When advising home blood pressure monitoring, care should be taken to recommend only the use of validated devices and to prefer the use of arm devices in order to avoid the uncertainty of an inadequate utilisation.