The Benefit of Unattended Automated Office Blood Pressure Measurement on the White-coat Effect: A Cross-sectional Study

Objective: To compare blood pressure (BP) and heart rate measured by attended and unattended automated office blood pressure measurement (AOBPM) versus home blood pressure measurement (HBPM) and the effect of unattended AOBPM on the classification of BP phenotypes. Materials and Methods: The cross-sectional study was conducted at the outpatient department in Siriraj Hospital, Thailand. All participants measured their office BP using attended and unattended techniques in random order and recorded home BP twice a day for consecutive 7 days. The agreement between office BP from both AOBPM methods and that from HBPM was analyzed using the Bland-Altman plot. The change in the proportion of each BP phenotype was also analyzed. Results: We included 114 participants. The mean age was 57.96 + 15.07 years. The average BP from attended AOBPM, unattended AOBPM, and HBPM were 150.52 + 16.12/81.77 + 11.04, 139.68 + 13.80/78.55 + 11.71, and 126.91 + 9.80/76.40 + 8.37 mmHg, respectively. The BP and heart rate measured by these techniques were significantly different (p-value of <0.001). Bland-Altman analysis showed the biases of attended and unattended SBP versus home SBP were 23.61 and 12.77 mmHg, respectively. Unattended AOBPM significantly decreased the numbers of patients classified as white-coat and sustained hypertension regardless of BP thresholds (p-value of <0.001 for both groups). Conclusion: Unattended AOBPM significantly minimizes the white-coat effect in real-life clinical practice and may help physicians avoid overdiagnosis of hypertension. Nevertheless, it does not replace HBPM.