What is the optimal interval between successive home blood  pressure readings using an automated oscillometric device?
OBJECTIVE
To clarify whether a shorter interval between three successive home blood pressure (HBP) readings (10 s vs. 1 min) taken twice a day gives a better prediction of the average 24-h BP and better patient compliance.


METHODS
We enrolled 56 patients from a hypertension clinic (mean age: 60 +/- 14 years; 54% female patients). The study consisted of three clinic visits, with two 4-week periods of self-monitoring of HBP between them, and a 24-h ambulatory BP monitoring at the second visit. Using a crossover design, with order randomized, the oscillometric HBP device (HEM-5001) could be programmed to take three consecutive readings at either 10-s or 1-min intervals, each of which was done for 4 weeks. Patients were asked to measure three HBP readings in the morning and evening. All the readings were stored in the memory of the monitors.


RESULTS
The analyses were performed using the second-third HBP readings. The average systolic BP/diastolic BP for the 10-s and 1-min intervals at home were 136.1 +/- 15.8/77.5 +/- 9.5 and 133.2 +/- 15.5/76.9 +/- 9.3 mmHg (P = 0.001/0.19 for the differences in systolic BP and diastolic BP), respectively. The 1-min BP readings were significantly closer to the average of awake ambulatory BP (131 +/- 14/79 +/- 10 mmHg) than the 10-s interval readings. There was no significant difference in patients' compliance in taking adequate numbers of readings at the different time intervals.


CONCLUSIONS
The 1-min interval between HBP readings gave a closer agreement with the daytime average BP than the 10-s interval.
Eguchi
Kazuo
K
Division of Cardiovascular Medicine, Department of Medicine, Jichi Medical University, Tochigi, Japan. ke112@jichi.ac.jp
Kuruvilla
Sujith
S
Ogedegbe
Gbenga
G
Gerin
William
W
Schwartz
Joseph E
JE
Pickering
Thomas G
TG
D000368:Aged; D001331:Automation / Q000295:instrumentation; D001794:Blood Pressure; D018660:Blood Pressure Monitoring, Ambulatory / Q000295:instrumentation / Q000379:methods*; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D006973:Hypertension / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009991:Oscillometry / Q000295:instrumentation; D010349:Patient Compliance; D013997:Time Factors