Comparison between an adapted protocol for home and ambulatory measurement for evaluating night-time blood pressure behaviour

Abstract

Background: The diagnosis and treatment of hypertension rely on the accuracy of blood pressure (BP) measurements obtained both in and out of the office during awake and sleep periods. Objective: To evaluate whether a home blood pressure monitoring (HBPM) protocol incorporating morning, afternoon, and evening measurements supports the assessment of blood pressure behaviour during sleep and enhances the diagnosis of hypertension. Methods: This cross-sectional study included 40 patients (73% women; age = 62.0 ± 13.2 years) who underwent 24-h ambulatory blood pressure monitoring (ABPM) and (five-day HBPM) with measurements taken across three time periods. The association between the sleep-wake dip recorded by ABPM and the night-day difference measured by HBPM was examined. Additionally, the sensitivity, specificity, predictive values, concordance index, Kappa coefficient, and area under the ROC curve (AUC) of mean BP values obtained from HBPM were compared with those from ABPM. Results: Mean BP values obtained from HBPM were 126.2 ± 13.3/79.2 ± 9.1 mmHg, (daytime), 125.9 ± 16.4/78.7 ± 10.5 mmHg (evening), and 126.1 ± 14.3/78.9 ± 9.6 mmHg (total). For ABPM, mean values were 120.3 ± 12.5/74.5 ± 8.9 mmHg (awake), 116.5 ± 10.9/69.3 ± 8.0 mmHg (asleep), and 119.4 ± 11.4/73.4 ± 8.0 mmHg (total). Total HBPM outperformed daytime and evening HBPM in detecting abnormalities on ABPM (daytime, night-time, and 24 h), with higher sensitivity, negative predictive value (NPV), AUC, concordance index, and Kappa coefficient. The correlation between the day-night dip in ABPM and the night-day difference in HBPM was weak. Conclusion: Including night-time measurements in the HBPM protocol improves the accuracy of hypertension diagnosis when compared to ABPM. However, the night-day BP difference captured by HBPM does not correspond to the day-night dip measured by ABPM. PLAIN LANGUAGE SUMMARY Blood pressure measurement devices for evaluating hypertensive patients Hypertension is a major modifiable risk factor for cardiovascular and cerebrovascular diseases, and also, is the main cause of morbidity and mortality worldwide. To diagnose and manage hypertension properly, it is crucial to measure blood pressure (BP) accurately. Blood pressure measurements should be taken during medical visits and at home through ambulatory blood pressure monitoring (ABPM) or home blood pressure monitoring (HBPM). Choosing the right device depends on individual needs. Often it is recommended a combination of clinic, ABPM or HBPM. The main disadvantage of HBPM is its inability to assess BP during sleep, and it is aggravated in Brazil by the lack of validated equipment for measurements during this period. Therefore, to fill this gap, this study proposed an adapted HBPM protocol, including measurements at night, executed immediately before bedtime. This study demonstrated that the incorporation of nocturnal BP measurements into the traditional HBPM protocol resulted in greater accuracy in the diagnosis of hypertension when compared to ABPM, although the night-time-daytime blood pressure difference in HBPM does not reflect the day-night dip of ABPM. The use of a method that has a lower cost, such as HBPM, can promote the evaluation of a greater number of patients, enabling greater control of BP levels, and consequently, lower morbidity and mortality in the long term.