A comparative study of an ambulatory blood pressure measuring device and a wrist blood pressure monitor with a position sensor versus a mercury sphygmomanometer.

Abstract

BACKGROUND: Self-measurements of blood pressure (BP) and 24-hour BP measurements are better predictors of cardiovascular mortality and morbidity than office BP measurements. The objective of this study was to compare the accuracy and precision of a wrist BP monitor with a position sensor (Omron 637IT) and of an ambulatory BP measuring monitor (ABPM; Nissei DS-250) with a mercury sphygmomanometer. METHODS: A total of 139 patients (69 women and 70 men) were included in the study. The BP of each subject was first measured with a mercury device using the same (left) arm. After this, the wrist monitor was used for BP measurement. Upon completion of the BP readings, 24-hour BP monitoring was performed using Nissei DS-250 monitors. Mean and standard deviations were calculated for all devices. In order to assess the agreement between the measurement methods, the Bland-Altman method and graphics were utilized. RESULTS: The mean systolic BP measured by the mercury device was 133.2+/-18.4 mmHg and the diastolic BP was 85.4+/-12.5 mmHg, whereas the digital device measured systolic BP as 135.7+/-17.2 mmHg and diastolic BP as 87.0+/-12.5 mmHg. The 24-hour BP measurement was 134.6+/-16.6 mmHg for systolic BP and 85.6+/-11.1 mmHg for diastolic BP. The difference with regard to systolic BP between the mercury and the Omron devices was -2.5+/-5.3 mmHg, which is within the AAMI standard. However, while the mean values of the differences between the mercury and ABPM devices remained under 5 mmHg, their standard deviation was above +/- 8 mmHg. For diastolic BP, the difference between all of the devices was below 5+/-8 mmHg. CONCLUSIONS: The wrist BP monitor produced results consistent with those of the mercury sphygmomanometer when both were compared with the results of the ABPM. As BP measurement with these devices is a practical and repeatable method, they can be used instead of ABPM in the diagnosis and monitoring of hypertension. However, there is a need for further comparative studies.