Effect of self-initiated and fully-automated self-measurement on blood pressure.

Self-measurement of blood pressure (BP) is regularly used to diagnose hypertension and to monitor BP at home. We recently showed that self-measurement of BP may elicit a pressor or 'auto-cuff' response. In this study we examined whether the pressor response is different between self-initiated and fully-automated BP measurement. We performed two randomized crossover studies in outpatients visiting a hypertension clinic. The first cohort of 52 participants performed six unattended self-initiated and six fully-automated BP measurements, while continuously monitoring BP and central haemodynamics using finger photoplethysmography. The second cohort consisted of 120 patients who performed three self-initiated and three fully-automated BP measurements. In the first cohort (mean age 61.2 ± 10.4 years, mean office BP 142.0 ± 19.9/82.5 ± 12.2 mmHg, 36.7% female) average systolic and diastolic BP increased by 7.3 ± 8.5/3.3 ± 4.0 mmHg in the group with self-initiated BP measurements, while BP increased by 3.3 ± 6.3/1.4 ± 3.0 mmHg during fully-automated measurements (p = 0.002/p = 0.002 for difference between groups). The higher BP increase during self-initiated BP measurements resulted from an increase in heart rate and cardiac output. In the second cohort (mean age 58.0 ± 14.1 years, mean office BP 153.6 ± 23.8/86.3 ± 14.0 mmHg, 44.1% female) self-initiated BP measurement resulted in a 2.1 ± 6.8/0.9 ± 4.0 mmHg higher systolic and diastolic BP compared with fully-automated self-measurement (p = 0.001/0.018). In conclusion, our findings suggest that self-initiated BP measurement using a fully-automated method results in a more reliable BP compared with a self-initiated semi-automated method by attenuating the auto-cuff response. These findings may have implications for the self-measurement of BP.