Compare 30-minute automated office blood pressure vs 24-hour ambulatory blood pressure monitoring: A prospective study

BACKGROUND: Ambulatory blood pressure monitoring (ABPM) is the reference standard for diagnosing hypertension (HTN), but its use in routine practice remains limited because of cost, availability, and patient burden. Automated office blood pressure (AOBP) has been proposed as a practical alternative, although its performance relative to ABPM remains uncertain. OBJECTIVES: To evaluate the agreement and diagnostic performance of 30-minute AOBP compared with 24-hour ABPM and to identify optimal cut-off values for detecting ambulatory hypertension. METHODS: In this prospective cohort study, 79 adults undergoing ABPM also underwent 30-minute AOBP measurement with automated readings every 5 minutes. The mean of the final six measurements was analyzed. Agreement was assessed using paired comparisons and Bland-Altman analysis. Diagnostic performance using receiver operating characteristic (ROC) analysis and agreement statistics. RESULTS: Thirty-minute AOBP values were consistently higher than ABPM measurements. Mean differences were +6.59/ + 7.27 mmHg for systolic/diastolic BP versus 24-hour ABPM and +3.73/ + 5.16 mmHg versus daytime ABPM (all p < 0.001). Bland-Altman analysis showed acceptable group-level agreement but wide limits of agreement. Sensitivity ranged from 84% to 96% and specificity from 28% to 79%. ROC analysis demonstrated good discrimination (AUC 0.77-0.87). The highest agreement with overall ABPM occurred at a cut-off of ≥140/84 mmHg (κ = 0.624). CONCLUSIONS: Thirty-minute AOBP showed good discrimination for elevated ambulatory blood pressure but systematically overestimated BP relative to ABPM. It may serve as a practical screening tool, although normal AOBP values cannot reliably exclude ambulatory HTN and confirmation with 24-hour ABPM remains necessary. CENTRAL ILLUSTRATION: Diagnostic Performance of 30-Minute Automated Office Blood Pressure Compared With 24-Hour Ambulatory Monitoring.