DAY-TO-DAY REPRODUCIBILITY OF NOCTURNAL BLOOD PRESSURE FALL (DIPPING) EVALUATED WITH WEARABLE AND HOME DEVICES IN HYPERTENSIVE PATIENTS

Abstract

Objective: Non-dipping status has been associated with increased risk of heart failure and cardiovascular events. However, its reproducibility when evaluated by means of ambulatory blood pressure monitoring (BPM) is often suboptimal. Wearable devices (WD) and home BPM devices equipped with nocturnal measurement function (HBPMN) offer the opportunity of estimating dipping status over different days thus potentially increasing precision owing to statistical averaging. We aimed to determine the reproducibility of nocturnal BP dipping estimated through a combined use of WD and HBPMN devices for daytime and night-time BP estimation within one week. Design and method: We recruited treated and untreated adult patients with hypertension. Patients underwent one week of home BP monitoring through a HBPMN device (NightView, OMRON Healthcare, HEM9601T-E3) and with an oscillometric WD (HeartGuide, OMRON Healthcare, HEM-6411T-MAE). Patients were asked to measure BP over one week with WD according to ESH-HBPM guidelines for daytime measurements and with HBPMN according to standard device settings for night-time measurements. Interclass correlation coefficient (ICC) was calculated to evaluate reproducibility. Results: 76 patients were included in the study. The main characteristics are summarised as follows: age (61±11.84 years), 32 (42%) females, BMI (28.12±4.90 Kg/m2). Most of them (98%) were treated hypertensives. Office systolic and diastolic BP were 134±4.43 mmHg and 80±4.84 mmHg, respectively. The average one-week systolic BP dipping was 16.14±9.44%. When we considered patients who had dipping assessment over at least the first 5 days (37 patients), intra-individual variability in the categorical definition of dipping status was observed (Figure 1) with a suboptimal reproducibility of average nocturnal BP fall (ICC 0.60). Conclusions: Nocturnal BP dipping estimated as continuous variable through the combined use of WD and HBPMN exhibits suboptimal reproducibility resulting in a variable day-by-day classification of patients according to their dipping status. Whether this reflects technical issues, or rather depends on the physiological variability of BP and sleeping patterns needs to be determined by future studies.