Background: We evaluated the agreement between office blood pressure (OBP) measured by a mercury sphygmomanometer (Sphyg) and an automatic (Auto) device without any observers, and compared Auto and Sphyg OBP with ambulatory blood pressure (ABP) and home blood pressure (HBP).
Methods: OBP was measured in 75 hypertensive patients at two sites using an automatic monitor without a doctor or a nurse present and by Sphyg during three clinic visits. Between visits, monitoring of ABP and HBP was also performed.
Results: The mean Auto OBP was similar to that of Sphyg OBP and the values were closely correlated (intraclass correlation coefficient=0.84 for systolic OBP and 0.91 for diastolic OBP); however, the difference between Auto and Sphyg systolic OBP (1.6 ± 8.2 mmHg) varied by the first office visit, sex, and the site. Auto systolic OBP was lower than both systolic awake ABP (137.1 ± 14.7 mmHg) and HBP (139.2 ± 15.6 mmHg). Auto systolic OBP and Sphyg OBP were similarly correlated with systolic awake ABP (both r=0.59, P<0.001). The mean Auto diastolic OBP was similar to that of Sphyg OBP (81.1 ± 11.3 vs. 80.3 ± 13.3 mmHg, P=0.20, intraclass correlation coefficient=0.91), and diastolic awake ABP and HBP. Auto diastolic OBP and Sphyg OBP were related to diastolic awake ABP (both r>0.68, P<0.001). In multivariable analyses, neither OBP measure was a significantly stronger predictor of out-of-office blood pressure than the other.
Conclusion: Auto systolic OBP measured without a doctor or a nurse present was lower than systolic awake ABP and HBP. Auto and rigorously assessed Sphyg OBP had similar means and were similarly related to awake ABP. Auto OBP might be an advantageous alternative to Sphyg measurements in the usual clinic setting.