Patient preferences for ambulatory blood pressure monitoring devices: Wrist-type or arm-type?

Abstract

Background Ambulatory blood pressure monitoring (ABPM) is important in evaluating average 24-hour blood pressure (BP) levels, circadian rhythm, sleeping BP and BP variability but many patients are reluctant to use standard ABPM devices. Methods We compared two validated ABPM devices, the BPro tonometric wrist monitor and the A&D TM-2430 oscillometric upper arm monitor, for agreement of recordings and acceptability in 37 hypertensive patients (aged 55±9 years). Results Successful BP measurements were less frequent with the wrist-type than the arm-type device during the sleeping (66.3% vs. 92.9%, P <0.01) and awake periods (56.2% vs. 86.5%, P <0.01). Comparable paired readings showed no significant difference in systolic BP but diastolic BP (DBP) values were higher with the wrist compared to the arm monitor (24-hour 89±13 vs. 85±14 mmHg, P <0.01) with similar differences awake and sleeping. Bland-Altman analysis showed some large discrepancies between individual arm and wrist monitor measurements. More patients found the wrist monitor more comfortable to use than the arm monitor. Conclusions Despite the difference in individual BP measurements and the systematic overestimation of DBP values with the BPro device, wrist monitors with good patient acceptability may be useful to facilitate ABPM in some patients to provide additional information about cardiovascular risk and response to antihypertensive therapies.

Direct Use of Clinical Tolerance Limits for Assessing the Degree of Agreement between Two Methods of Measuring Blood Pressure

“…Zeng et al concluded that there were "considerable discrepancies" for individual readings between the two devices, but the wrist device was still preferable because of its convenience. 12 They did not measure the degree of agreement or disagreement.…”

“…An ingenious advantage of assessing the agreement by direct use of clinical tolerance limits is that the researcher cannot avoid setting up these limits for assessing the agreement that many workers, such as Poloni et al 2 and Zeng et al, 12 do not do while using the Bland-Altman method and make a subjective assessment. Readers deserve to be informed about the clinical tolerance limits against which the agreement has been assessed.…”

“…Zeng et al 12 compared two validated ambulatory BP monitoring devices—the BPro tonometric wrist monitor and the A & D TM-2430 oscillometric upper arm monitor—for agreement in 37 hypertensive patients. Each patient was measured at several points in time.…”

“…The data contain 912 readings of SBP and diastolic BP (DBP) by the two monitors at different points in time during the day and the night. These exclude the outliers with extremely high readings (see Zeng et al 12 for the entire procedure they followed). I used night DBP readings by the two devices for this example (n = 231).…”

“…The plot of these differences against the average readings by the two monitors is seen in Figure 2, along with the lines at the Bland-Altman limits. Zeng et al concluded that there were “considerable discrepancies” for individual readings between the two devices, but the wrist device was still preferable because of its convenience 12 . They did not measure the degree of agreement or disagreement.…”