A multicentre study on unattended automated office blood pressure measurement in treated hypertensive patients

Aims: Unattended automated office blood pressure (uAutoOBP) may eliminate white-coat effect. In the present study, we studied its relationships to attended office blood pressure (BP) and ambulatory BP monitoring (ABPM).

Material and methods: Stable treated hypertensive subjects were examined in four Czech academic hypertension centres. uAutoOBP was measured with the BP Tru device; attended BP was measured six times: three times with auscultatory method (AuscOBP) by the physician followed optionally by three oscillometric measurements (OscOBP). ABPM was performed within one week from the clinical visit.

Results: Data on 172 subjects aged 63.7 ± 12.4 years with AuscOBP 127.6 ± 12.1/77.6 ± 10.0 mm Hg are reported. uAutoOBP was by 8.5 ± 9.0/3.0 ± 6.1 mm Hg lower than AuscOBP. The AuscOBP-uAutoOBP difference increased with the AuscOBP level and it did not depend on any other factor. OscOBP differed by 8.6 ± 8.6/1.9 ± 5.7 mm Hg from uAutoOBP. 24-hour mean BP was by 4.2 ± 12.1/3.5 ± 7.8 mm Hg lower than AuscOBP and by 4.3 ± 11.0/0.5 ± 6.9 mm Hg higher than uAutoOBP; the correlation coefficients of 24-hour mean BP with AuscOBP and with uAutoOBP did not differ (p for difference ≥.13). In the lowest BP group (systolic AuscOBP <120 mm Hg or diastolic AuscOBP <70 mm Hg), both AuscOBP and uAutoOBP were lower than 24-hour mean BP, while in the highest BP group (systolic AuscOBP ≥140 mm Hg or diastolic AuscOBP ≥90 mm Hg), they were higher.

Conclusions: Compared to uAutoOBP, attended BP measurement gives higher values, both when measured with auscultatory or oscillometric method. Inter-individual variability of AutoOBP – uAuscOBP difference, as well of uAutoOBP – ABPM difference, is large. We did not prove that uAutoOBP would be associated to 24-hour ambulatory BP more closely than attended BP.