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Cardiac rehabilitation (CR) improves outcomes for patients with ischemic heart disease or heart failure but is underused. New strategies to improve access to and engagement in CR are needed. There is considerable interest in technology-facilitated home CR. However, little is known about patient acceptance and use of mobile technology for CR.
The aim of this study was to develop a mobile app for technology-facilitated home CR and seek to determine its usability.
We recruited patients eligible for CR who had access to a mobile phone, tablet, or computer with Internet access. The mobile app includes physical activity goal setting, logs for tracking physical activity and health metrics (eg, weight, blood pressure, and mood), health education, reminders, and feedback. Study staff demonstrated the mobile app to participants in person and then observed participants completing prespecified tasks with the mobile app. Participants completed the System Usability Scale (SUS, 0-100), rated likelihood to use the mobile app (0-100), questionnaires on mobile app use, and participated in a semistructured interview. The Unified Theory of Acceptance and Use of Technology and the Theory of Planned Behavior informed the analysis. On the basis of participant feedback, we made iterative revisions to the mobile app between users.
We conducted usability testing in 13 participants. The first version of the mobile app was used by the first 5 participants, and revised versions were used by the final 8 participants. From the first version to revised versions, task completion success rate improved from 44% (11/25 tasks) to 78% (31/40 tasks;
With participant feedback and iterative revisions, we significantly improved the usability of a mobile app for CR. Patient expectations for using a mobile app for CR include tracking health metrics, introductory training, and sharing data with providers. Iterative mixed-method evaluation may be useful for improving the usability of health technology.
Cardiac rehabilitation (CR) is an evidence-based program of exercise training, risk factor management, education, and counseling that improves outcomes for patients with heart disease [
Technology has the potential to facilitate health interventions and motivate patients to improve health behaviors, including for the secondary prevention of cardiovascular disease [
Using the TPB and UTAUT2, we developed a theory-based mobile app for technology-facilitated home CR. We tested the mobile app in patients eligible for CR, obtained feedback, and iteratively made revisions to the mobile app to improve its usability. Additionally, we interviewed participants about physical activity, CR, and mobile app use to better understand how to implement technology-facilitated home CR. The aims of this study were to determine the usability of the VA FitHeart mobile app and to analyze factors contributing to its use.
We conducted an observational study of Veteran use of a mobile Web app, VA FitHeart. The mobile app was designed to be used as a tool for home CR and includes physical activity goal setting, logs for physical activity and health measures (eg, blood pressure, pulse, weight, glucose, cholesterol, and mood), health education, reminders, and feedback (
Veterans attending the outpatient cardiology clinic at the VA Puget Sound Health Care System in Seattle, WA were screened for enrollment in the study. Eligibility criteria included the ability to speak English, age ≥21, and eligibility for CR, defined as myocardial infarction, percutaneous coronary intervention, or cardiac surgery in the past year or having chronic stable angina or heart failure. Participants were excluded if they were not eligible for CR. Participants meeting inclusion criteria were asked to participate in additional screening to participate in a study about a mobile app for CR. Participants were excluded if they did not have access to a mobile phone, tablet, or computer with Internet access. This study was reviewed and approved by the institutional review board at the VA Puget Sound Health Care System. All participants provided written, informed consent.
Study staff demonstrated the mobile app to participants in person and asked participants to complete prespecified tasks with the mobile app while study staff observed the participants. Tasks demonstrated by study staff included setting a physical activity goal, making a physical activity entry, viewing a fitness graph, making a weight entry, and viewing an educational module. After the conclusion of the demonstration, participants were asked to complete the demonstrated tasks independently. Study staff recorded task completion success if the participant was able to successfully complete the task.
Following testing, participants completed questionnaires using REDCap electronic data capture tools hosted at the VA [
We conducted two separate semistructured interviews with Veterans enrolled in the study. The first interview was conducted before usability testing and was centered on physical activity and the use of technology. The second interview was conducted before usability testing, asking specific questions about the functionality of the mobile app. All interviews took place in person at the VA Puget Sound Health Care System in Seattle, WA in a private office. Both interviews had semistructured interview guides that included open-ended questions and prompts for elicitation of additional detail (
Screenshots of VA FitHeart, a mobile app for cardiac rehabilitation.
Descriptive statistics of range and mean were used for quantitative questionnaire responses. To compare responses before and after, we performed a two-tailed
From January 27, 2016 to October 24, 2016, we enrolled 15 participants in usability testing (
The first version of the mobile app was used by the first 5 participants, and revised versions were used by 8 participants. Two participants were unable to complete testing because of technical difficulties with accessing the servers in the preproduction testing environment during server downtimes. From the first version to revised versions, task completion success rate improved from 44% (11/25 tasks) to 78% (31/40 tasks;
Task completion success and patient-reported usability and likelihood of using the mobile app on initial and revised versions of the mobile app. Task completion success was the percentage of tasks successfully completed. Usability was score on the System Usability Scale (scale 0-100, with 100 being the best usability). Likely to use app was self-rated likelihood of use (scale 0-100, with 100 being the highest likelihood).
Patient-reported factors influencing mobile app use on initial and revised versions of the mobile app. Items were rated on a scale of 0 to 100, with 100 being the best rating. *
Emergent themes about mobile technology use were categorized by UTAUT2 construct (
Many participants expect that VA FitHeart would be beneficial.
I think that the idea of an app that records all of the information that this app is doing will be very valuable. Actually somewhat of a motivation for me to do this thing.
Participants desired that a mobile app for CR be able to track goals, physical activity, and other health measures such as blood pressure, heart rate, weight, blood glucose, and diet.
Although there were suggestions for additional features to the mobile app, such as the ability to integrate with sensors and automatically transfer data, it was commented that this was not essential.
Memorizing, writing it down and then getting it into your computer, if that was all done while you’re doing activities and stuff that would be a big help. But if they can’t, this is still a good app. Still helpful.
Several aspects of ease of use of the mobile app emerged. Participants appreciated simplicity.
It was pretty easy...I like that it’s simple.
The flow is very simple.
Vision and size of text were cited as a barrier by many participants.
The only downside I see for me is with my vision; the fonts are a little small. I would definitely need to use my reading glasses to read it.
Prominent display of key features was cited as a facilitator of ease of use.
The settings to change your goals are very easy to reach and very prominent.
Although some users commented on functions that were not as intuitive and harder to find, it was recognized that with more experience and familiarity, this problem could be overcome.
I’m not used to this. Once I get used to it, I’ll know where everything is.
One general barrier to ease of use mentioned by participants was the use of passwords and codes. This did not emerge as a barrier specific to our app, but participants were not required to enter a password during the testing session.
Participants often mentioned a desire to share their data with their providers.
I like the fact that I can put all of that and track it, and that my doctors can as well. I can show my doctor what I’ve been working on.
There was also interest in communicating with providers through the app. Family and peer support were reported to influence mobile technology use. The mobile app does feature a link to an online social networking site for patients with heart disease, but social networking was infrequently mentioned.
A desire for hands-on initial training on how to use the mobile app emerged as an important theme.
Initially, training with a technical person, instead of me relying on myself.
Expectations for additional help varied, including online, telephone, and family or peer support.
If I had problems I’d try to find out how to fix it on this or call you.
But I’ve got 3 boys that are all pretty much wizards at it, but I’m not. I’m sure I can learn it or if they punch in the application so that it could come right up, I’d be fine.
Habit was frequently mentioned by participants, both with regard to their use of technology and related to participating in physical activity. Habit was also linked by many Veterans to their previous military service. Our interview guides did not specifically probe participants about habit, making the prominent emergence of habit notable. In the discussion of habit, some participants described how memory and learning contribute to the development of habitual use of technology.
Memory appears to play a dual role in use of the technology—in remembering to use the technology and how to use the technology.
Something to remind me. But, I’m going to have to set a schedule of when I actually do this.
It’s a problem with my memory. The program to me seems fine if I can remember how to go through it.
Learning was discussed often as a period of trial and error where users would become more facile with using the app with greater experience.
Once I learned this app and spent just a little bit of time with it, I’ll be good with it. I don’t see any problem with it.
Ultimately, these efforts are expected to result in habitual use of VA FitHeart.
If I were to [use the app] religiously, every day do it, then it’d be force of habit.
Most comments about pleasure derived from using technology were general in nature. Comments about VA FitHeart itself were less strongly pleasurable in nature, but generally positive.
But I like the looks of the app and I like what it’s set up to do.
Though participants mentioned price and cost related to other technologies and mobile apps, price value was infrequently mentioned linked to our mobile app, which will be free for general use.
I think in the end, you could save people, or patients, money.
In our interviews, we identified many of the common barriers and facilitators to physical activity and participation in CR that have been described in previous studies (
Attitudes expressed included general attitudes toward physical activity, as well as comments related to health benefits and the influence of other medical conditions. Many participants commented on subjective norms including the influence of pets, family, and health care providers. Participants frequently mentioned themes relating to perceived behavior control such as goals, habit, motivation, work (as either a facilitator or barrier), and travel or transportation.
We identified one notable emergent theme that does not clearly fall within a single TPB construct and that has not been well described before: the role of military service in physical activity.
Though we specified a priori categories, the topic of military service was mentioned so frequently by our population that we created an emergent category for military service, which may be uniquely important to our patient population. In our population of US military Veterans, almost all Veterans reported their time of military service as a physically active time in life. Their time in military service was often central to their experience related to physical activity.
When I joined the service I was very fit. I usually did physical activity in the morning and sometimes in the afternoon also, an average of 2.5 hours a day, 4 to 5 days a week.
Additionally, many Veterans described their time after discharge as a particularly inactive time.
I hadn’t worked out since the military. It had been like 18 years since I’d set foot in a gym.
We found that iteratively revising a mobile app for CR based on user feedback resulted in significant improvements in the usability of the mobile app. Using a theory-based approach, we revealed interest in using a mobile app to track physical activity and health measures and to share data with providers. Patients expected to have training on how to use the mobile app. On the basis of participant comments, establishing habit, both with regard to physical activity and mobile app use, is anticipated to be a key contributor to adoption of this technology.
This is the first theory-based investigation of the usability of a mobile app for CR. It is known that interventions based on theory are more likely to be effective [
Patients in our study desired the ability to track physical activity and health measures with an easy-to-use mobile app, confirming findings from previous studies [
It has previously been reported that people have little desire to share their personal fitness data with their providers [
Many participants expressed an expectation for in-person training on use of the mobile app, in addition to on-demand help online, via telephone, or from family and friends. Previous studies of older adults have also revealed a preference for in-person training and the influence of family and friends [
Habit was frequently and prominently mentioned by Veterans as a factor that will be important, both for using the mobile app and participating in physical activity. UTAUT2 describes experience and habit as related concepts, with experience being necessary but not sufficient for establishment of habit [
Several limitations to our findings should be considered. We had a small sample size of Veterans and only one female, so our population may not fully represent the population or non-Veteran populations. As not all eligible patients agreed to participate, our findings may not be representative of the entire eligible population. Due to our small sample size, we may not have truly achieved thematic saturation of all factors associated with the use of mobile technology for CR. However, our sample did provide valuable feedback that resulted in improved usability. Additionally, we studied VA FitHeart in a usability testing environment and not in a real-world environment. Further testing is needed in a real-world environment to determine whether other factors are important to use.
With participant feedback and iterative revisions, we significantly improved the usability of a mobile app for CR. Patient expectations for using a mobile app for CR include tracking health metrics, introductory training, and sharing data with providers. Iterative theory-based mixed-method evaluation may be useful for improving the usability of health technology.
Mobile Application Use questionnaire.
Interview guides.
Screening and enrollment of participants.
Quotations related to concepts from the extended unified theory of acceptance and use of technology.
Quotations related to concepts from the Theory of Planned Behavior.
cardiac rehabilitation
System Usability Scale
Theory of Planned Behavior
Unified Theory of Acceptance and Use of Technology
Unified Theory of Acceptance and Use of Technology extension for consumer use of technology
Veterans Affairs
The authors appreciate the support of the Veterans Health Administration Office of Connected Care, Veterans Health Administration National Cardiology Office, Veterans Health Administration Office of Rural Health, and Veterans Affairs Office of Information and Technology in the development of VA FitHeart.
This study was funded by the US Department of Veterans Affairs Virtual Specialty Care Quality Enhancement Research Initiative (QUE 15-282), the Seattle Institute for Biomedical and Clinical Research, the John L. Locke Jr. Charitable Trust, and the Alpha Phi Foundation. ALB is supported by Career Development Award #16-5150 from the VA Health Services Research and Development Program. The views expressed in this study are those of the authors and do not necessarily reflect the position or policy of the VA or the US Government.