Diagnostic performance of an automatic blood pressure measurement device, Microlife WatchBP Home A, for atrial fibrillation screening in a real-world primary care setting. Issue 6 (15th June 2017)

• Record Type: Journal Article
• Authors: Chan, Pak-Hei; Wong, Chun-Ka; Pun, Louise; Wong, Yu-Fai; Wong, Michelle Man-Ying; Chu, Daniel Wai-Sing; Siu, Chung-Wah
• Is Part Of: BMJ open. Volume 7:Issue 6(2017)
• Publication Date: 2017-06-15
• Subjects: Atrial fibrillation -- microlife -- screening; Medicine -- Research -- Periodicals; 610.72
• DOI: 10.1136/bmjopen-2016-013685
• Languages: English
• ISSNs: 2044-6055

Abstract

Abstract : Objective: To evaluate the diagnostic performance of a UK National Institute for Health and Care Excellence-recommended automatic oscillometric blood pressure (BP) measurement device incorporated with an atrial fibrillation (AF) detection algorithm (Microlife WatchBP Home A) for real-world AF screening in a primary healthcare setting. Setting: Primary healthcare setting in Hong Kong. Interventions: This was a prospective AF screening study carried out between 1 September 2014 and 14 January 2015. The Microlife device was evaluated for AF detection and compared with a reference standard of lead-I ECG. Primary outcome measures: Diagnostic performance of Microlife for AF detection. Results: 5969 patients (mean age: 67.2±11.0 years; 53.9% female) were recruited. The mean CHA2 DS2 -VASc (C : congestive heart failure [1 point]; H : hypertension [1 point]; A2 : age 65-74 years [1 point] and age ≥75 years [2 points]; D : diabetes mellitus [1 point]; S : prior stroke or transient ischemic attack [2 points]; VA : vascular disease [1 point]; and Sc : sex category [female] [1 point])score was 2.8±1.3. AF was diagnosed in 72 patients (1.21%) and confirmed by a 12-lead ECG. The Microlife device correctly identified AF in 58 patients and produced 79 false-positives. The corresponding sensitivity and specificity for AF detection were 80.6% (95% CI 69.5 to 88.9) and 98.7% (95% CI 98.3 to 98.9), respectively. Among patients with a false-positive by the Microlife device, 30.4% had sinus rhythm, 35.4% had sinus arrhythmia and 29.1% exhibited premature atrial complexes. With the low prevalence of AF in this population, the positive and negative predictive values of Microlife device for AF detection were 42.4% (95% CI 34.0 to 51.2) and 99.8% (95% CI 99.6 to 99.9), respectively. The overall diagnostic performance of Microlife device to detect AF as determined by area under the curves was 0.90 (95% CI 0.89 to 0.90). Conclusions: In the primary care setting, Microlife WatchBP Home was an effective means to screen for AF, with a reasonable sensitivity of 80.6% and a high negative predictive value of 99.8%, in addition to its routine function of BP measurement. In a younger patient population aged <65 years with a lower prevalence of AF, Microlife WatchBP Home A demonstrated a similar diagnostic accuracy.