Evaluation of the Use of Home Blood Pressure Measurement Using Mobile Phone-Assisted Technology: The iVitality Proof-of-Principle Study.

Background: Mobile phone-assisted technologies provide the opportunity to optimize the feasibility of long-term blood pressure ( BP) monitoring at home, with the potential of large-scale data collection. Objective: In this proof-of-principle study, we evaluated the feasibility of home BP monitoring using mobile phone-assisted technology, by investigating ( 1) the association between study center and home BP measurements; ( 2) adherence to reminders on the mobile phone to perform home BP measurements; and ( 3) referrals, treatment consequences and BP reduction after a raised home BP was diagnosed. Methods: We used iVitality, a research platform that comprises a Website, a mobile phone-based app, and health sensors, to measure BP and several other health characteristics during a 6-month period. BP was measured twice at baseline at the study center. Home BP was measured on 4 days during the first week, and thereafter, at semimonthly or monthly intervals, for which participants received reminders on their mobile phone. In the monthly protocol, measurements were performed during 2 consecutive days. In the semimonthly protocol, BP was measured at 1 day. Results: We included 151 participants ( mean age [ standard deviation] 57.3 [ 5.3] years). BP measured at the study center was systematically higher when compared with home BP measurements ( mean difference systolic BP [ standard error] 8.72 [ 1.08] and diastolic BP 5.81 [ 0.68] mm Hg, respectively). Correlation of study center and home measurements of BP was high ( R= 0.72 for systolic BP and 0.72 for diastolic BP, both P<. 001). Adherence was better in participants measuring semimonthly ( 71.4%) compared with participants performing monthly measurements ( 64.3%, P=. 008). During the study, 41 ( 27.2%) participants were referred to their general practitioner because of a high BP. Referred participants had a decrease in their BP during follow-up ( mean difference final and initial [ standard error] -5.29 [ 1.92] for systolic BP and -2.93 [ 1.08] for diastolic BP, both P<. 05). Conclusion: Mobile phone-assisted technology is a reliable and promising method with good adherence to measure BP at home during a 6-month period. This provides a possibility for implementation in large-scale studies and can potentially contribute to BP reduction.