P2684Blood pressure lowering by using a self-care focused smartphone application for patients after myocardial infarction
Authors: Leosdottir M , Sjolin I , Sandberg C , Olsson A , Back M , Schiopu A , Gonzalez M , Ogmundsdottir Michelsen H 
Published: October 2019

Abstract

Background
We have previously shown that complementing traditional cardiac rehabilitation (CR) with a web-based smartphone application designed to support self-control of risk factors can improve secondary prevention outcomes, including lower blood pressure (BP).

Purpose
To explore possible explanations for better BP control among patients with myocardial infarction (MI) receiving access to a smartphone application as a complement to traditional CR, compared to patients receiving traditional CR alone.

Methods
Data from a multi-centre randomized controlled trial that included 150 patients with MI (81% men, 60.4±8.8 years) was used. All patients participated in traditional CR. In addition, patients in the intervention group (APP, n=101) had access to the application. Patients received automated positive feedback on normal values and all registered data was viewed by CR nurses twice weekly. As previously reported, APP patients achieved a 9 mmHg larger reduction in systolic BP than usual care (UC) patients at 2-months follow-up (p=0.02). In the current analysis we assessed differences between APP and UC patients in the number of visits and telephone contacts with the CR clinic, number of reported BP measurements and number and type of interventions on account of out-of-range BP during the first 6 months of follow-up, using Mann-Whitney and chi-square tests.

Results
There was no difference in the median (IQR) number of visits to a CR nurse or physician (APP 2 (2–3) vs UC 2 (2–3), p=0.8) or telephone contacts ((APP 2 (1–4) vs UC 2 (1–4), p=0.8) between the groups. Approximately one in ten telephone contacts were initiated because of BP, with no difference between the groups (p=0.8). Out of 101 APP patients 75 reported BP values through the application, ranging from 1–175 BP values/patient (median 6 (IQR 0–34)). Most measurements (90%) were normal. Grouping clinic visits, telephone contacts due to BP and BP reports through the application as a composite for the number of BP measurements the CR personnel were exposed to during follow-up, there was a significant difference between the groups (APP 9 (4–36) vs UC 3 (2–3), p<0.0001). There was a small non-significant difference between the groups in the proportion of patients where an intervention was performed by the CR nurse on account of out-of-range BP (i.e. medication adjustments, new measurement scheduled) (APP 22% vs UC 12%, p=0.1).

Conclusion
While CR personnel were exposed to significantly more BP measurements from patients using a self-care focused smartphone application as a complement to traditional CR, most BP measurements reported through the application were normal and there was no difference in the number of interventions performed on account of out-of-range BP values. Automated positive feedback on in-range BP measurements, increased patient responsibility with better adherence to BP lowering medication could be possible explanations to improved BP control.

Acknowledgement/Funding
The faculty of Medicine, Lund University, Lund, Sweden