Evaluation of diagnostic accuracy of nocturnal home bp monitoring in hemodialysis patients: a pilot study

Objective: A unique advantage of ambulatory blood pressure monitoring (ABPM) is that this technique enables the assessment of blood pressure (BP) during the period of sleep, facilitating the diagnosis of nocturnal hypertension. This study aimed to compare ABPM with home BP monitoring (HBPM) performed with a novel device that is designed to obtain daytime and also automated nighttime BP recordings in the assessment of nocturnal hypertension and detection of non-dipping BP pattern among patients on hemodialysis. Design and method: Within a period of 2 weeks, 70 stable patients on thrice-weekly hemodialysis underwent assessment of BP with 2 methods: (i) 44-hour interdialytic ABPM (20-min intervals; Microlife WatchBP O3 device) and (ii) HBPM (duplicate morning and evening BP recordings for 7 days and 3 BP recordings per night for 3 nights over the 3-day interdialytic interval; Microlife WatchBP Home N). Results: The mean age of the patients was 65.3 (±13.3) years; 45 (64%) were males, and 62 (88.7%) were receiving antihypertensive therapy. The average ambulatory daytime and nighttime SBP/DBP were 122.8±15/68.7±10.5 mmHg and 117.2±16.5/63.4±10.2 mmHg, respectively. The mean [95% confidence interval (CI)] difference between home daytime SBP and ambulatory daytime SBP was 8.61 (6.1, 11.2) mmHg. Similarly, the mean (95% CI) difference between home nighttime SBP and ambulatory nighttime SBP was 5.94 (3.5, 8.4) mmHg. In receiver-operating-characteristics (ROC) analysis, the technique of HBPM provided high accuracy for the detection of an average ambulatory daytime SBP equal or higher than 135 mmHg [area under the curve (AUC): 0.934; 95% CI: 0.871-0.996] as well as for the detection of an average ambulatory nighttime SBP equal or higher than 120 mmHg (AUC: 0.876; 95% CI: 0.794-0.957). Of the overall population, 44 patients (63%) were classified as non-dippers by ABPM and 42 (60%) by HBPM. There was acceptable agreement between these 2 techniques in the identification of patients with a non-dipper BP pattern (77%, k-coefficient = 0.324). Conclusions: The present study shows that among patients on hemodialysis, HBPM serves as a reliable alternative to 44-hour interdialytic ABPM for the diagnosis of nocturnal hypertension and detection of non-dipping BP status.