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

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.