Comparison of unattended, attended and routine clinic systolic blood pressure measurements and determinants of blood pressure difference between attended and unattended BP - Journal of Human Hypertension

Unattended systolic blood pressure (SBP) was found to be lower than both attended and routine clinic measurements in a randomized outpatient study. The trial compared unattended automated office BP (uAOBP) with attended AOBP (aAOBP) and routine clinic BP, reporting the mean SBP differences among methods. Linear regression showed no significant association between the aAOBP-uAOBP difference and demographics or comorbidities, suggesting the gap is not driven by patient characteristics. The design randomized patients to measurement sequence to minimize order effects, and the authors note that the difference is most pronounced when aAOBP is performed first and clinic SBP is ≥130 mmHg, with 140 mmHg aAOBP corresponding to about 135 mmHg on uAOBP.

Previously reported heterogeneity among studies is acknowledged, with mean differences between aAOBP and uAOBP ranging from as little as 2.7 mmHg to as high as 8.6 mmHg in prior work, highlighting methodological influences. The current findings align with concerns that unattended measurements may better reflect true SBP by avoiding the white-coat effect in settings where patients are familiar with the environment. The study emphasizes that unattended BP reduces measurement bias and supports adopting uAOBP in clinical practice. It strengthens the methodological framework for comparing BP measurement strategies in diverse outpatient populations.