Objective: It is recommended to wait at least 1 min between blood pressure (BP) readings. However, there is insufficient evidence on the utility of this recommendation using a validated automatic device. The aim was to assess differences in BP according to the waiting time between BP readings.
Patients and methods: The study was designed as a cross-sectional descriptive study in hypertensive patients attended in primary care.Patients were seated for 5 min before six baseline BP readings: three BP measurements with no waiting time [immediate readings (IR)] between them and three BP measurements with 1 min of waiting time [waiting readings (WR)] between each reading, in random order. The intraclass correlation coefficient was calculated between IR and WR mean BP measurements, with 95% confidence intervals (CIs).
Results: We included 150 hypertensive patients, 49.3% women, 65.6 (12.8) years of age. The mean systolic blood pressure (SBP) values for IR and WR measurements were 137.2 (95% CI 134.2-140.2) and 137.8 (95% CI 134.8-140.8) mmHg, respectively. The mean diastolic blood pressure (DBP) values for IR and WR measurements were 79.4 (95% CI 77.5-81.4) and 79.7 (95% CI 77.7-81.8) mmHg, respectively. Intraclass correlation coefficient between IR and WR was 0.959 (95% CI 0.943-0.970) and 0.926 (95% CI 0.898-0.946) for SBP and DBP, respectively. The mean difference between both methods for SBP and DBP was -0.60 (95% CI -1.79 to 0.5) and -0.27 (95% CI -1.33 to 0.77) mmHg, respectively.
Conclusion: We found a good agreement between waiting or not waiting 1 min between office BP readings. This demonstrates that both methods of BP measurement appear to be interchangeable.