Correlations between different measures of clinic, home, and ambulatory blood pressure in hypertensive patients

Objectives: It is not well known how clinic, home, and ambulatory measures of blood pressure (BP) correlate with each other. We performed this study to clarify the level of agreement among these different BP measures. Materials and methods: We enrolled 56 hypertensive patients (mean age: 60±14 years; 54% were females). The study consisted of three clinic visits, self-monitoring of home BP between visits, and ambulatory blood pressure (ABP) monitoring at the second visit. Patients were given a home BP monitor programmed to automatically take three consecutive readings at fixed intervals of 1 min. The associations between clinic BP (mercury sphygmomanometer and HEM-5001), home BP (the average of morning and evening, second and third BP readings), and average awake ABP were compared using the intraclass correlation for agreement and Bland-Altman plots. Results: The averages of clinic sphygmomanometer, clinic HEM-5001, awake ABP, and home BP were 129 of 77, 131 of 76, 131 of 79, and 133 of 77 mmHg, respectively. Clinic BP by HEM-5001 was strongly correlated with that of mercury sphygmomanometer. Home systolic blood pressure was moderately correlated with awake ABP, but mercury diastolic blood pressure (DBP) was more closely correlated with awake DBP than home DBP. Conclusion: Clinic BP measured with the automated monitor could be used as an alternative for the evaluation of BP in the office. Under rigorously standardized conditions, clinic and home BP could be used as an alternative to awake ABP.