Manual office blood pressure (BP) is still recommended for diagnosing hypertension. However, its predictive value is decreased by errors in measurement technique and the white-coat effect. The errors can be eliminated by automated office BP (AOBP) measurement taking multiple readings with the subject resting quietly alone. Therefore, use of AOBP in clinical practice requires a threshold value for hypertension diagnosis. The aim of the present study was to determine an AOBP threshold corresponding to the 140/90 mmHg manual office BP using data from a large random population sample.Design and method:
In 2145 subjects (mean age 47.3 ± 11.3 years) randomly selected from a Brno population aged 25–64 years, BP was measured using manual mercury and automated office sphygmomanometers.Results:
Manual systolic (mean difference 6.39 ± 9.76 mmHg) and diastolic (mean difference 2.50 ± 6.54 mmHg) BP was higher than the automated BP. According to polynomial regression, automated systole of 131.06 (95% CI 130.43–131.70) and diastole of 85.43 (95% CI 85.03–85.82) corresponded to the manual BP of 140/90 mmHg. Using this cut-off, the white-coat response was present in 24% of subjects with elevated manual BP, while 10% had masked hypertension and 11% masked uncontrolled hypertension. In individuals with masked uncontrolled hypertension, only AOBP was associated with the urinary albumin-creatinine ratio, while there was no association with manual BP.Conclusions:
AOBP of 131/85 mmHg corresponds to the manual BP of 140/90 mmHg. This value may be used as a threshold for diagnosing hypertension using AOBP. However, outcome-driven studies are required to confirm this threshold.