Skip main navigation

A Physical Activity and Diet Just‐in‐Time Adaptive Intervention to Reduce Blood Pressure: The myBPmyLife Study Rationale and Design

Originally publishedhttps://doi.org/10.1161/JAHA.123.031234Journal of the American Heart Association. 2024;13:e031234

    Abstract

    Background

    Smartphone applications and wearable devices are promising mobile health interventions for hypertension self‐management. However, most mobile health interventions fail to use contextual data, potentially diminishing their impact. The myBPmyLife Study is a just‐in‐time adaptive intervention designed to promote personalized self‐management for patients with hypertension.

    Methods and Results

    The study is a 6‐month prospective, randomized‐controlled, remotely administered trial. Participants were recruited from the University of Michigan Health in Ann Arbor, Michigan or the Hamilton Community Health Network, a federally qualified health center network in Flint, Michigan. Participants were randomized to a mobile application with a just‐in‐time adaptive intervention promoting physical activity and lower‐sodium food choices as well as weekly goal setting or usual care. The mobile study application encourages goal attainment through a central visualization displaying participants' progress toward their goals for physical activity and lower‐sodium food choices. Participants in both groups are followed for up for 6 months with a primary end point of change in systolic blood pressure. Exploratory analyses will examine the impact of notifications on step count and self‐reported lower‐sodium food choices. The study launched on December 9, 2021, with 484 participants enrolled as of March 31, 2023. Enrollment of participants was completed on July 3, 2023. After 6 months of follow‐up, it is expected that results will be available in the spring of 2024.

    Conclusions

    The myBPmyLife study is an innovative mobile health trial designed to evaluate the effects of a just‐in‐time adaptive intervention focused on improving physical activity and dietary sodium intake on blood pressure in diverse patients with hypertension.

    Registration

    URL: https://www.clinicaltrials.gov; Unique identifier: NCT05154929.

    Nonstandard Abbreviations and Acronyms

    JITAI

    just‐in‐time adaptive intervention

    mHealth

    mobile health

    Clinical Perspective

    What Is New?

    • There is an opportunity to leverage mobile health technologies to improve care in the general population as well as in low‐income and underrepresented racial and ethnic groups, although there are limited long‐term and randomized‐controlled efficacy data supporting the use of mobile health interventions to sustain behavior change.

    • The myBPmyLife study is a prospective, randomized‐controlled, remotely administered clinical trial designed to evaluate a just‐in‐time adaptive intervention promoting increased physical activity and lower‐sodium food choices for patients with hypertension.

    What Are the Clinical Implications?

    • The myBPmyLife study is a dynamic, mobile health intervention delivered to patients from both an academic medical center and a federally qualified health center network and has the potential to address prior gaps in mobile health research and to improve blood pressure control in patients with hypertension.

    Hypertension is a leading cause of disability and death in the United States and worldwide.1, 2 Significant disparities in hypertension burden exist, especially across vulnerable populations. Self‐management of hypertension through lifestyle modification, like physical activity and limiting dietary sodium intake, can enhance blood pressure (BP) control in patients with hypertension.3 The American Heart Association guidelines recommend 150 minutes per week of moderate‐intensity physical activity and a daily sodium intake of <2400 mg.4 Unfortunately, achieving these goals is difficult for many individuals, and clinicians often struggle to help their patients make healthy choices that are sustained over time.

    Mobile telephone use is growing among people of all ages and across racial and socioeconomic groups. Eighty‐five percent of Americans are estimated to own a smartphone,5 and 50% of Americans track some aspect of their health digitally, with 40% owning a wearable device.5, 6 Such trends are also true for Black and older adults.7, 8 Therefore, there is an opportunity for improving care through mobile health (mHealth) technologies in the general population as well as in low‐income and underrepresented racial and ethnic groups. Despite this rapidly growing sphere of mHealth technologies, there are limited long‐term and randomized‐controlled efficacy data supporting the use of mHealth interventions to promote and sustain behavior change, and most studies have been designed as static rather than dynamic interventions.9 Static interventions, however, fail to account for users' changing environments, may not be relevant for all users, and do not necessarily capture the processes that underlie health behavior change.9

    The myBPmyLife study is a prospective, randomized‐controlled, remotely administered clinical trial designed to evaluate a just‐in‐time adaptive intervention (JITAI) promoting increased physical activity and lower‐sodium food choices for patients with hypertension. JITAIs are novel intervention designs that incorporate real‐time data streams from wearable devices to push interventions (ie, notifications) to users at key moments when there is a higher likelihood of their success.10, 11 The study enrolled patients from both an academic medical center and a federally qualified health center network and is designed to address prior gaps in mHealth research by using community engagement to develop and test a JITAI in 2 different communities. We will assess if the change in dietary sodium intake, change in average step count, or both mediate the effects of the intervention on the change in systolic BP (SBP) over 6 months.

    Methods

    The authors declare that all supporting data are available within the article.

    Study Design

    The myBPmyLife study is a prospective, randomized‐controlled, remotely administered clinical trial (ClinicalTrials.gov NCT05154929) that enrolled 608 patients with hypertension from the University of Michigan Health, an academic medical center, and the Hamilton Community Health Network (HCHN), a network of federally qualified health center clinics in Flint, Michigan. The study was designed using a community‐engaged approach, as previously described, which allowed for input into trial design, protocol development, and recruitment strategies from patients, community members, and clinical organizational representatives.8, 12, 13, 14 After undergoing screening and consent, participants in both groups received a smartwatch (Fitbit Versa 2) and a wireless BP monitor (Omron Evolv BP7000) (Figure 1). Participants were randomized in a 1:1 manner to either the intervention group, where they receive an mHealth intervention, or to the control group, where they receive usual care. The study was approved by the University of Michigan Institutional Review Board (HUM00205845), and the data will be made available on study completion.

    Figure 1. Virtual consent and enrollment strategy in the myBPmyLife study.

    BP indicates blood pressure; and EMR, electronic medical record.

    Study Procedures

    Screening, Eligibility, and Consent

    The myBPmyLife study launched on December 9, 2021. For University of Michigan Health patients, research staff used the electronic health record to identify patients with hypertension based on the presence of an appropriate International Classification of Diseases, Tenth Revision (ICD‐10), code of I10. Potentially eligible participants were recruited through weekly emails. In contrast, a list of potentially eligible HCHN participants was generated by HCHN staff using their electronic health record also based on the presence of the ICD‐10 code of I10. This was provided to the study team at the University of Michigan Health. Potentially eligible participants were recruited by University of Michigan Health staff through weekly emails and text messages. For HCHN, we prioritized participants for recruitment efforts with upcoming appointments in 2022 to identify those potentially more likely to enroll. For both sites, recruitment occurred in batches until study recruitment targets were met. Participants were considered eligible if they had self‐reported hypertension with no changes in their antihypertensive therapies in the preceding 4 weeks and owned a smartphone with a compatible Apple iOS version 12.0+ or Android OS version 8.0+. Participants with contraindications to physical activity or following a low‐sodium diet were excluded from the study. Participants who already owned a smartwatch were requested to wear the study smartwatch or were allowed to use their own smartwatch if they owned an equivalent or newer version of the device. Full inclusion and exclusion criteria are in Table 1.

    Table 1. Inclusion and Exclusion Criteria
    Inclusion criteria
    1. Aged ≥18 years at screening and able to provide consent.

    2. Self‐reported history of hypertension and no hypertensive medication changes in the past 4 weeks.

    3. A smartphone with a compatible Apple or Android operating system installed and able to download and use the myBPmyLife app, including accepting all permissions.

    4. An email address.

    5. Fluent in spoken and written English.

    6. Signed written informed consent.

    Exclusion criteria
    1. Contraindication to performing physical activity or following a sodium restriction diet. The participant must have been able to walk and eat on his/her own without assistive devices.

    2. Unstable symptoms or markedly elevated BP at enrollment (defined as SBP >180 mm Hg and diastolic BP >120 mm Hg).

    3. Known secondary causes of hypertension (eg, adrenal insufficiency and pheochromocytoma) or end‐stage renal disease.

    4. Difficulty using an upper arm BP cuff because of biceps size or end‐stage renal disease or difficulty comfortably wearing a smartwatch.

    5. Wrist too large to wear a smartwatch comfortably. This was assessed by asking participants if they have ever had difficulty wearing a watch in the past due to the band being too small.

    6. Daily sodium intake <1500 mg/d as measured by the sodium screener.

    7. Currently pregnant or planning to become pregnant in the next 6 months.

    8. Previously diagnosed with heart failure.

    9. Another household member enrolled in the study.

    10. Enrolled in another wearable device study or in a competing investigational study, as per investigator discretion.

    BP indicates blood pressure; and SBP, systolic BP.

    At the time of their consent appointment, patients were assisted in downloading the study application MyDataHelps from the App Store or Google Play Store, a mobile application developed by CareEvolution, LLC, for conducting health sciences studies. Patients were then sent a unique invitation to join the study within the mobile application using either their telephone or email address. Informed consent occurred by telephone within MyDataHelps, although participants had the option to use videoconferencing or screen‐sharing applications as needed for technical issues. Once informed consent was obtained, participants reported their confidence in selecting lower‐sodium food choices and performed a baseline assessment of their sodium intake using the Block Sodium Screener (NutritionQuest, Berkeley, CA).15 Those with an estimated daily sodium intake of <1500 mg/d, as measured by the Block Sodium Screener, were excluded from the study.

    Once consented, participants were scheduled for enrollment appointments, and Fitbit Versa 2 smartwatches and Omron Evolv BP 7000 Wireless BP monitors were mailed to their homes. Participants were randomized by study staff to the intervention or control groups of the study in a 1:1 manner, using site‐stratified block randomization with randomly chosen block sizes of 2, 4, and 6. Neither participants nor study staff were masked to randomization assignment.

    Enrollment

    After receiving the smartwatch and BP cuff, enrollment appointments were performed by telephone. During these appointments, participants were assisted in pairing their smartwatches with their smartphones, downloading the Omron Connect application on their smartphones, pairing their smartphone and BP cuff, and configuring their smartwatches to suppress notifications from other health and wellness applications. Participants in both groups received the myDataHelps application (Figure 2), which has the intervention and control content embedded within the study application. Participants in both groups are followed up for 6 months.

    Figure 2. Images of the myDataHelps application configured for myBPmyLife intervention participants.

    A, Home dashboard. Participants can track progress toward goal achievement, search for lower‐sodium food options, and report their food choices. B, Salt dashboard. Participants can track their lower‐sodium food selections each day in addition to searching for lower‐sodium foods, reporting their selections, and reviewing recent dietary notifications. C, Steps dashboard. The Fitbit Versa 2 tracks participants' step counts. Participants can also review recent physical activity notifications. D, Blood pressure (BP) dashboard. Participants can measure their BPs and monitor their BP trends. E, Resources dashboard. This page shows hyperlinks to help participants better navigate and use the mobile application. Participants can use this page to restore account connectivity, access help guides, and contact the study team.

    Participants in the intervention group of the study answered several surveys to assist in the subsequent tailoring of the intervention. This included setting time preferences around notification receipt and indicating which day of the week they most often go grocery shopping. In addition, participants selected alternatives to 5 frequently consumed higher‐sodium food choices, as identified by the Block Sodium Screener. Selection of alternative foods was facilitated by the Nutritionix database, a national food database, embedded within the mobile application. Participants also answered a mobility assessment (“Are you able to walk for 10 minutes without restriction?”)16 and the 1 question Self‐Rated Health Questionnaire, modified from the 12‐item Short Form Health Survey (“In general, would you say your health is excellent, very good, good, fair, or poor?”).17

    During their enrollment appointments, all participants received instructions on how to check their BP consistent with American Heart Association recommendations.18 Their measurements were synced to the OMRON Connect application via Bluetooth. Participants with markedly elevated BPs during their enrollment appointments, defined as a SBP of >220 mm Hg or as an SBP of >180 mm Hg or diastolic BP of >120 mm Hg with symptoms (eg, chest discomfort or neurologic symptoms), were considered ineligible given the anticipated need for medication changes. In these cases, participants were referred for medical attention as appropriate and withdrawn from the study as screen failures. These individuals were subsequently recontacted in 4 weeks to reevaluate eligibility for the study and, if now eligible, reconsented for the study. Following enrollment, a 7‐day baseline period was instituted for all participants (including the intervention group) to ascertain their baseline step count.

    Study Intervention

    The intervention incorporates multiple components designed on the basis of the behavioral change strategies of goal setting, prompts, visualizations, and feedback. This includes push notifications as part of a JITAI and a weekly goal‐setting exercise to encourage increased physical activity and the selection of lower‐sodium food choices. Participants receive feedback on their progress toward achieving those goals within the study mobile application (Figure 2).

    The core of the intervention is the delivery of push notifications promoting physical activity and lower‐sodium food choices (Table 2). Physical activity notifications are designed to disrupt sedentary behavior (eg, to stand up or stretch) and to encourage low‐level physical activity (eg, bouts of 250 to 500 steps) (Table 2). Activity notifications are tailored on the basis of the time of day, day of the week (weekend or weekday), weather, community, and mobility. In contrast, dietary notifications are designed to encourage participants to select lower‐sodium food choices and often include suggestions for lower‐sodium alternatives to participants' commonly consumed or purchased foods. Dietary notifications are tailored according to the time of day, day of the week (weekend, weekday, or grocery day), community, and confidence in selecting lower‐sodium food choices. Both physical activity and diet notifications are tailored on the basis of participants' communities with notifications composed of a mixture of community‐ and expert‐generated notifications.12 All notifications link to the appropriate page in the mobile application, and a subset are personalized based on participants' names. Embedded in the clinical trial is a microrandomized trial. Microrandomized trials are used to optimize JITAIs.19 Participants are randomized to receive or not receive a notification at each of 4 daily time points (ie, decision points) with participants having a 25% probability of receiving a notification at each decision point. Thus, on average, participants receive 1 activity or low‐sodium notification each day. Consistent with the purpose of microrandomized trials, these data will be analyzed separately from the clinical trial and used to improve the JITAI in future studies.19

    Table 2. Examples of Community‐ and Expert‐Generated Push Notifications to Promote Increased Physical Activity and Lower‐Sodium Food Choices
    SuggestionTypeTime of dayDay of weekCommunity‐ vs expert‐generated
    [Name], meat is really easy to over salt. Try adding smoked paprika instead.Low‐sodium dietEveningWeekdayCommunity (Ann Arbor, MI)
    The snow is not going to shovel itself! That is a lot of exercise right there, [Name]!ActivityAfternoonWeekdayCommunity (Ann Arbor, MI)
    Low‐salt breakfast idea: make breakfast cookies with oatmeal, chocolate chips, and different types of fruits and nuts. Then you can just grab it and go!Low‐sodium dietMorningWeekendCommunity (Flint, MI)
    If you have evening errands, look for the farthest parking spot from the door. You can get more steps!ActivityEveningWeekdayCommunity (Flint, MI)
    Looking for a midday boost? Try unsalted nuts and cheese to give you a burst of energy!Low‐sodium dietLunchWeekdayExpert
    A walk would be great for your body and mind! Can you get 250 steps now?ActivityLunchWeekdayExpert

    Activity notifications were additionally tailored according to weather and mobility, whereas dietary notifications were additionally tailored according to confidence in selecting lower‐sodium food choices.

    In addition to microrandomized notifications, participants receive notifications encouraging them to set weekly goals for their step count and lower‐sodium food choices and weekly reminders to check their BP. Inclusive of all notification types, participants receive 10 notifications/week on average. In addition to notifications, participants have access to the mobile application MyDataHelps that connects with their smartwatch and BP cuff. The mobile application contains unique content configured by the study investigators and developed using a community‐engaged approach. The mobile application allows participants to (1) engage in self‐monitoring of their activity, lower‐sodium food choices, and BP trends, (2) set goals each week and track their progress toward those goals through a central visualization, and (3) search for lower‐sodium food alternatives (Figure 2).

    Participants in the control group downloaded the mobile study application to enable data collection and survey completion, although it delivers none of the intervention functionality. Participants receive 1 notification each week reminding them to check their BP. Participants in the control group were also provided a handout with online resources for individuals with hypertension, including suggested mobile applications, to allow the study team to isolate the impact of their intervention compared with that of mobile technology alone.

    Study Procedures

    Every 2 months, participants in both groups receive a follow‐up telephone call from a study coordinator to assess for medication changes and cardiovascular events, and surveys are reassigned within the mobile application around general quality of life using the Self‐Rated Health Questionnaire and sodium intake using the Block Sodium Screener. Participants in the intervention group additionally reselect alternatives to frequently consumed higher‐sodium foods if these food categories have changed. Throughout the study period, participants who are nonadherent with weekly BP measurements or smartwatch wear time receive automated notifications from the study application encouraging them to take their BP and wear their smartwatch. Participants receive up to 2 automated notifications from the study application followed by a telephone call thereafter if needed. Subsequent contact occurs by email or text messages. Participants also have access to a technical support line during business hours to address hardware or software issues.

    For both groups, incentives for participation include the study devices and financial compensation. After 2 months, participants are allowed to keep the smartwatch and BP cuff if they complete study surveys and engage with the mobile intervention. In addition, participants received $25 at 2 and 4 months and $50 at 6 months for survey completion.

    End‐of‐Study Procedures

    At 6 months, participants are asked to take 1 set of 3 BP readings, each separated by 1 minute. Participants also review changes in their health history and medications with the study coordinator and are assigned surveys in the mobile application. At the end of the study, participants receive instructions on removing the study application from their smartphones to cease passive data collection by the study team.

    Adverse Event Description and Ascertainment

    Anticipated adverse events include anxiety, discomfort associated with being asked personal questions about their health history, skin irritation from the smartwatch, symptoms with exercise, and those related to participants' underlying conditions. If the study team is notified of a potentially serious adverse event through the electronic health record (University of Michigan Health participants) or through participant self‐report (both sites), data are provided on an approved case report form to an independent medical monitor who ascertains relatedness and makes recommendations about the safety of ongoing study participation. To minimize bias, the medical monitor reviews adverse events blinded to treatment assignment. The investigator follows all adverse events until resolution or stabilization. We have different processes for adverse event assessment between the 2 sites because study staff do not have access to the electronic health record for HCHN participants. Events that substantially impact diet, activity, or quality of life result in study withdrawal.

    Statistical Considerations

    Study End Points

    The primary outcome is a change in SBP (as a continuous variable) from baseline to 6 months as collected from the Omron BP cuff (Table 3). In all cases, sets of BPs were defined as the average of 3 BP measurements, collected within a 10‐minute window. We will include sets of baseline BP measurements obtained within 7 days of enrollment with the set of BP measurements closest to enrollment used as the baseline value in analyses of the primary outcome. For sets of 6‐month BP measurements collected at the end of the study, we will include sets of BP measurements obtained 1 week before and up to 28 days after 180 days with the set of BP measurements closest to 180 days used in analyses of the primary outcome.

    Table 3. Study End Points
    OutcomesMeasurement
    PrimaryChange in SBP from baseline to 6 months
    Exploratory

    1. Change in mean daily sodium intake between baseline and 6 months (Block Sodium Screener)

    2. Change in mean daily step count between baseline and 6 months (Fitbit smartwatch)

    3. Change in diastolic BP from baseline to 6 months

    4. Longitudinal changes in SBP over 6 months

    5. Change in quality of life between baseline and 6 months (SRH Questionnaire)

    Process measureSystem Usability Scale

    Primary, exploratory, and process measure study end points are given. BP indicates blood pressure; SBP, systolic BP; and SRH, self‐Rated Health.

    Exploratory analyses will include changes between baseline and 6 months for the following measures: quality of life using the Self‐Rated Health Questionnaire, mean daily sodium intake as assessed by the Block Sodium Screener, diastolic BP collected from the Omron BP cuff, and mean daily step count as assessed using the Fitbit smartwatch. In addition, we will measure longitudinal changes in SBP (eg, mean weekly and monthly) using the Omron BP cuff and user burden through the System Usability Scale as well as through engagement measures within the mobile application.20, 21, 22 We will also assess if the change in dietary sodium intake, change in average step count, or both mediate the effects of the intervention on the change in SBP over 6 months.

    Statistical Analysis

    The primary analysis will be a complete‐case, modified intention‐to‐treat analysis that will examine the association between the treatment groups (control versus intervention) and change in SBP from baseline, using a generalized linear model fit with generalized estimating equations.23, 24, 25 For all analyses, compound symmetry will be used for correlation structure. Subsequent sensitivity analyses will evaluate the robustness of the primary results. This will include missingness by varying the inclusion criteria for valid measurements, such as the time frame for allowable sets of SBP measurements (eg, including sets obtained up to 28 days before and after the 6‐month mark), the number of measurements needed for a set (eg, including sets of only 1 or 2 SBP measurements at baseline and 6 months), and comparing the 6‐month BP measurement between groups controlling for the baseline BP measurement. Secondary end points will be analyzed similarly but with longitudinal analyses including time interaction terms.

    For all analyses, baseline clinical characteristics will be described as means with SDs for continuous symmetric variables and medians with interquartile ranges for skewed continuous variables. Categorical variables will be presented as counts and percentages. We will perform Student t tests for bivariate comparisons between continuous variables and χ2 tests for comparisons across categorical variables comparing intervention and control groups. The level of significance for hypothesis testing will be set at P<0.05.

    Pretrial Sample Size Calculation

    The primary end point for this study is powered for the change in SBP between baseline and 6 months. We estimated sample size using the following parameters: a 3–mm Hg difference in the change in BP, an SD of 10, a type I error rate of 0.05, a type II error rate of 0.10, and an estimated overall attrition rate between 25% and 30%.26, 27, 28, 29 A large overall attrition rate was adopted because of the uncertainty surrounding retention rates of underrepresented populations in mHealth interventions (eg, individuals who are older or have low income). At an attrition rate of 25%, the sample size was estimated to be 294 participants per group, and at 30%, the estimate was 306 participants per group. On the basis of these numbers, we recruited 300 participants per group. This calculation was conducted using R, version 4.0.3.

    Data Flow and Security

    All participants are assigned a study identifier when recruited. All identifiable information is stored on password‐protected University of Michigan Health computers behind a firewall. All analytic data sets contain only arbitrary identifiers without names or any Health Insurance Portability and Accountability Act–protected data elements. In addition, data from participants' smartwatches and smartphones and from the electronic health record are stored on cloud systems with storage processes that comply with Health Insurance Portability and Accountability Act and other federal guidelines.

    Results

    The myBPmyLife study launched on December 9, 2021, with 486 participants enrolled as of March 31, 2023. Participants are predominantly from the University of Michigan Health (394 [81.1%]). Their mean age is 61.2 years (SD, 13.5 years), with 72.8% of participants being of White race, and 48.8% identifying as male sex. Self‐reported comorbidities include diabetes in 110 (22.6%) participants and depression in 96 (19.8%) participants. There are 148 (30.5%) participants who reported regularly using mobile health applications, and 167 (34.4%) who reported wearing a smartwatch before this study. Displayed in Table 4 are the baseline characteristics of the study population. Enrollment was completed on July 3, 2023. After 6 months of follow‐up is complete, it is expected that results will be available in the spring of 2024.

    Table 4. Baseline Clinical Characteristics

    CharacteristicAnn Arbor, MI (N=394)Flint, MI (N=92)Total (N=486)
    No. or mean% or SDNo. or mean% or SDNo. or mean% (SD)
    Age, yOverall64.312.047.911.361.213.5
    SexFemale19048.25762.024750.8
    Male20351.53437.023748.8
    Other10.311.120.4
    Self‐reported raceAmerican Indian or Alaska Native00.000.000.0
    Asian5012.700.05010.3
    Black307.63942.46914.2
    Native Hawaiian or other Pacific Islander00.000.000.0
    White30978.44548.935472.8
    Other41.055.491.9
    Multiple10.333.340.8
    EthnicityHispanic102.533.3132.7
    Self‐reported from medical historyDiabetes8722.12325.011022.6
    High cholesterol18847.73437.022245.7
    Chronic kidney disease194.866.5255.1
    Coronary artery disease256.333.3285.8
    Atrial fibrillation or flutter287.199.8377.6
    Stroke123.022.2142.9
    Depression6917.52729.39619.8
    Do you regularly use any mobile health applications?13434.01415.214830.5
    Did you wear a smartwatch before participating in this study?14336.32426.116734.4

    Data are displayed for 486 participants enrolled as of March 31, 2023.

    Discussion

    mHealth interventions have the potential to help clinicians and patients improve the diagnosis, treatment, and longitudinal management of hypertension and other cardiovascular conditions.10, 30 In the myBPmyLife study, we will assess if the change in dietary sodium intake, change in average step count, or both mediate the effects of the intervention on the change in SBP over 6 months. All participants have access to a mobile application that encourages physical activity, lower‐sodium food choices, and self‐monitoring. Most notably, this study has the potential to improve BP self‐management for millions of Americans with hypertension, including groups historically underrepresented in mHealth such as those with limited access to health care.

    The myBPmyLife study brings innovations in its study design and addresses limitations of prior mHealth studies.3, 31 First, we used a community‐engaged research approach to guide the intervention design and trial implementation. Second, the study adapted 2 JITAIs in order to deliver tailored notifications to participants with hypertension. Third, we are using microrandomization to understand which intervention components are most effective and in what contexts, enabling future intervention optimization.19, 32

    It is important to note the limitations of the study. First, enrollment is restricted to individuals with a compatible smartphone, which could limit generalizability. However, smartphone ownership is broad and growing in the United States.5, 33 Second, the study only recruited from 2 health systems in Michigan, with most participants recruited from the academic medical center, which could affect the study's generalizability. Third, all data are collected digitally. As a result, obtaining study data was dependent on participants' adherence to watch wear and opening the study mobile application to sync their data. Such factors associated with digital data collection could be affected by unanticipated technical issues as well as the diverse levels of technological competency among participants. Finally, we had different approaches for adverse event collection between the 2 communities, with the study team having access to the electronic health record only for University of Michigan Health participants. Despite these limitations, studies have shown that the effect of intensive monitoring (ie, electronic health record reporting) versus limited monitoring (ie, self‐reporting) has minimal impact on trial outcomes or clinical conclusions.34

    In conclusion, the myBPmyLife study uses innovative research approaches and cardiovascular risk reduction strategies to improve hypertension self‐management. JITAI's focus on improving physical activity and dietary sodium intake could improve BP control in patients with hypertension. As a digital trial, it can be repurposed for studying JITAIs in other conditions and with other communities with limited access to health care.

    Sources of Funding

    The study received a grant from the American Heart Association (AWD014891).

    Disclosures

    Dr Golbus receives funding from the National Institutes of Health (NIH) (L30HL143700, 1K23HL168220‐01). Dr Dorsch receives funding from the Agency for Health Research and Quality, the National Institute of Aging, the National Heart, Lung, and Blood Institute, and the American Health Association. Dr Skolarus receives funding from the National Institute of Aging, the National Institute of Minority Health and Health Disparities, and the American Health Association. Dr Nallamothu receives funding from the NIH, VA Health Services Research & Development, American Heart Association, and Janssen. He also receives compensation as Editor‐in‐Chief of Circulation: Cardiovascular Quality & Outcomes, a journal of the American Heart Association. Finally, he is a coinventor on US utility patent number US15/356012 (US20170148158A1) entitled “Automated Analysis of Vasculature in Coronary Angiograms,” which uses software technology with signal processing and machine learning to automate the reading of coronary angiograms, held by the University of Michigan. The patent is licensed to AngioInsight, Inc, in which Dr Nallamothu holds ownership shares and receives consultancy fees. The remaining authors have no disclosures to report.

    Acknowledgments

    We acknowledge Kimberly Warden, LPN, Michael Giacalone, MD, and the wonderful staff at Hamilton Community Health Network for their help in recruitment.

    Footnotes

    * Correspondence to: Michael P. Dorsch, PharmD, MS, Department of Clinical Pharmacy, College of Pharmacy, University of Michigan, 428 Church St, Ann Arbor, MI 48109. Email:

    *Drs Golbus and Jeganathan are joint first authors.

    For Sources of Funding and Disclosures, see page 9.

    This article was sent to Francoise A. Marvel, MD, Guest Editor, for review by expert referees, editorial decision, and final disposition.

    REFERENCES

    eLetters(0)

    eLetters should relate to an article recently published in the journal and are not a forum for providing unpublished data. Comments are reviewed for appropriate use of tone and language. Comments are not peer-reviewed. Acceptable comments are posted to the journal website only. Comments are not published in an issue and are not indexed in PubMed. Comments should be no longer than 500 words and will only be posted online. References are limited to 10. Authors of the article cited in the comment will be invited to reply, as appropriate.

    Comments and feedback on AHA/ASA Scientific Statements and Guidelines should be directed to the AHA/ASA Manuscript Oversight Committee via its Correspondence page.