A comparative trial of blood pressure monitoring in a self-care kiosk, in office, and with ambulatory blood pressure monitoring

Abstract

Abstract Background Automated measurement of blood pressure (BP) in designated BP kiosks have in recent years been introduced in primary care. If kiosk blood pressure (BP) monitoring provides results equivalent to in-office BP or daytime ambulatory BP monitoring (ABPM), follow-up of adult patients could be managed primarily by self-checks. We therefore designed a comparative trial and evaluated the diagnostic performance of kiosk- and office-based BP (nurse- versus physician-measured) compared with daytime ABPM. Methods A trial of automated BP monitoring in three settings: a designated BP kiosk, by nurses and physicians in clinic, and by ABPM. The primary outcome was systolic and diastolic BP, with respective diagnostic thresholds of ≥135 mmHg and/or ≥ 85 mmHg for daytime ABPM and kiosk BP and ≥ 140 mmHg and/or ≥ 90 mmHg for office BP (nurse- and physician-measured). Results Compared with daytime ABPM, mean systolic kiosk BP was higher by 6.2 mmHg (95% confidence interval [CI] 3.8–8.6) and diastolic by 7.9 mmHg (95% CI 6.2–9.6; p < 0.001). Mean systolic BP taken by nurses was similar to daytime ABPM values (+ 2.0 mmHg; 95% CI − 0.2–4.2; p = 0.071), but nurse-measured diastolic values were higher, by 7.2 mmHg (95% CI 5.9–9.6; p < 0.001). Mean systolic and diastolic physician-measured BPs were higher compared with daytime ABPM (systolic, by 7.6 mmHg [95% CI 4.5–10.2] and diastolic by 5.8 mmHg [95% CI 4.1–7.6]; p < 0.001). Receiver operating characteristic curves of BP monitoring across pairs of systolic/diastolic cut-off levels among the three settings, with daytime ABPM as reference, demonstrated overall similar diagnostic performance between kiosk and nurse-measured values and over the curve performance for physician-measured BP. Accuracy with nurse-measured BP was 69.2% (95% CI 60.0–77.4%), compared with 65.8% (95% CI 56.5–74.3%) for kiosk BP. Conclusions In this study kiosk BP monitoring was not comparable to daytime ABPM but could be an alternative to in-office BP monitoring by trained nurses. The diagnostic performance of kiosk and nurse-measured BP monitoring was similar and better than that of physician-measured BP. Trial registration ClinicalTrials.gov (NCT04488289) 27/07/2020.