LOW AGREEMENT BETWEEN HOME BLOOD PRESSURE MONITORING AND 24-HOUR AMBULATORY MONITORING IN RESISTANT HYPERTENSION: THE MERCURY STUDY

Objective: Home Blood Pressure Monitoring (HBPM) and Ambulatory Blood Pressure Monitoring (ABPM) capture different aspects of out-of-office blood pressure (BP) behavior and may not be directly comparable. Such differences may interfere with therapeutic decisions, but their impact in resistant hypertension (RH) remains unexamined. The MERCURY study evaluated the agreement between a standardized 7 day-HBPM protocol and 24-hour ABPM in patients with RH.Design and method: We recruited 38 patients with RH (mean age: 65.9 ± 11.8 years; 69% women; average of 3.9±1.5 antihypertensive medications) from a public tertiary hypertension center, who sequentially underwent 24-hour ABPM and 7-day HBPM. HBPM was performed using patients’ own devices following a verification procedure that evaluated measurement technique, ensured proper understanding of the HBPM protocol by the patient, and compared readings from the patient’s device with those from a standard device. Mean BP values from HBPM were compared with awake BP means from ABPM using paired t-tests, while agreement between the methods was assessed through Bland-Altman plots and intraclass correlation coefficients (ICC). Results: Mean systolic BP (SBP) was significantly higher with ABPM than HBPM (129.3 ± 12.3 mmHg vs. 124.2 ± 11.8 mmHg; p=0.009), while mean diastolic BP (DBP) was similar (76.8 ± 10.3 mmHg vs. 76.8 ± 9.7 mmHg; p=1.0). Agreement between methods was low for SBP (ICC = 0.482) and moderate for DBP (ICC = 0.663). Bland-Altman plots are shown in Figure 1. Despite the near-zero bias, the wide limits of agreement indicate high heterogeneity between the methods. Considering a BP target of <130/80 mmHg, concordance between methods in classifying patients as on-target or off-target was 65% for SBP and 70% for DBP, which indicates that one in three patients with RH would be misclassified depending on the method used. Conclusions: The agreement between HBPM and 24-hour ABPM in individuals with RH was low, especially for SBP. HBPM and ABPM should be viewed as complementary rather than interchangeable in the management of patients with RH.