Validity and applicability of a new recording method for hypertension

Abstract

Introduction and objectives: Blood pressure measurement methods and conditions are determinants of hypertension diagnosis. A recent British guideline recommends systematic 24-h ambulatory blood pressure monitoring. However, these devices are not available at all health centers and they can only be used by 1 patient per day. The aim of this study was to test a new blood pressure recording method to see if it gave the same diagnostic results as 24-h blood pressure monitoring.

Methods: One-hour blood pressure monitoring under routine clinical practice conditions was compared with standard method of day time recording by analyzing the coefficient of correlation and Bland-Altman plots. The Kappa index was used to calculate degree of agreement. Method sensitivity and specificity were also analyzed.

Results: Of the 102 participants, 89 (87.3%) obtained the same diagnosis regardless of method, with high between-method agreement (κ= 0.81; 95% confidence interval, 0.71-0.91). We observed robust correlations between diastolic (r=0.85) and systolic blood pressure (r=0.76) readings. Sensitivity and specificity for the new method for diagnosing white coat hypertension were 85.2% (95% confidence interval 67.5%-94.1%) and 92% (95% confidence interval, 83.6%-96.3%), respectively.

Conclusions: One-hour blood pressure monitoring is a valid and reliable method for diagnosing hypertension and for classifying hypertension subpopulations, especially in white coat hypertension and refractory hypertension. This also leads to a more productive use of monitoring instruments.

Keywords: Ambulatory blood pressure monitoring; Atención primaria; Hipertensión de bata blanca; Monitorización ambulatoria de la presión arterial; Primary care; White coat hypertension.