Table 1.

Summary of studies included in the review (N=15).

Title		Author, year	Sample size	Health focus	Recruitment criteria (as defined by the study authors)	DHIa purpose	Country	Methods of data collection	Digital requirements needed to participate in the study	Principal findings
Studies exploring the views on and experiences with DHIs
	Community Engagement in the Development of an mHealth-Enabled Physical Activity and Cardiovascular Health Intervention (Step It Up): Pilot Focus Group Study	Ceasar et al [57], 2019	16	CVDb	African-American individuals at risk of CVD, as they were recruited from an area with the highest burden of CVD in Washington, DC	mHealthc app containing motivational messages and educational content to promote physical activity with the aim of reducing the risk of developing CVD	United States	Interviews and focus groups	Participants were required to own a smartphone and were provided with a Fitbit Charge 2 device	The main themes emerging from the focus groups and interviews include perceived benefits, perceived barriers, perceived susceptibility, cues to action, and self-efficacy
	Young African American Women’s Participation in an mHealth Study in Cardiovascular Risk Reduction: Feasibility, Benefits, and Barriers	Kathuria-Prakash et al [58], 2019	40	CVD	African-American females at risk of CVD, as they had at least two risk factors	mHealth intervention included 4 sessions of CVD risk reduction education and 6-month smartphone CVD risk reduction monitoring	United States	Self-complete questionnaires	Participants received a smartphone device and wireless blood pressure machine for the study	60% (n=23) of participants reported that the interventions were easy or very easy to maintain, and 90% (n=35) reported that the app was easy or very easy to use. A total of 60% (n=24) of the participants observed that their family’s nutrition improved “a lot” or “a medium amount,” and many participants noted positive changes in their children’s diets. Only 8% (n=3) of the participants cited the time or cost required to prepare healthy foods as barriers to implementing dietary changes
	SMARTWOMAN: Feasibility Assessment of a Smartphone App to Control Cardiovascular Risk Factors in Vulnerable Diabetic Women	Wenger et al [59], 2019	14	CVD	African-American individuals with known T2DMd but no known CVD	The use of a Fitbit to control cardiovascular risk factors such as blood glucose levels, daily steps, and blood pressure as well as SMS text message reminders and encouragement for using the Fitbit	United States	Self-complete questionnaires	Smartphones and Fitbits were provided to all participants for the purpose of the study	The use of this app resulted in high patient satisfaction and motivation for participants, and it reinforced healthy behavior regarding cardiovascular health
	A Cardiovascular Health and Wellness Mobile Health Intervention Among Church-Going African Americans: Formative Evaluation of the FAITH! App	Brewer et al [53], 2020	9	CVD	African-American individuals with CVD risk factors due to their ethnicity	mHealth (app) to promote CVD health by tracking physical activity and diet and providing health information from cardiovascular health care professionals	United States	Focus groups	N/Ae	FAITH! app users reported high satisfaction and a positive impact on health-promoting behavior, improving their cardiovascular health; cultural tailoring, education modules, and social network were facilitators of the success
	Time to Listen: a Mixed-Method Study Examining Community-Based Views of Mobile Technology for Interventions to Promote Physical Activity	Claudel et al [54], 2020	16	CVD	African-American females who had obesity or were overweight and thus regarded as at risk of CVD	This study investigates the use of mHealth DHIs through focus groups and surveys	United States	Focus groups	N/A	Participants had a high attachment to mobile phones and high technology adoption. The need for cultural and community-level customization and collaboration with the community was emphasized
	British South Asian Patients’ Perspectives on the Relevance and Acceptability of Mobile Health Text Messaging to Support Medication Adherence for Type 2 Diabetes: Qualitative Study	Prinjha et al [52], 2020	67	T2DM	South Asian individuals with prediagnosed T2DM	This study explored participants’ opinions on the use of mHealth (SMS text messages) through focus groups to aid the development of future SMS text message interventions for this population group	United Kingdom	Focus groups	N/A	Short messages are acceptable; messages should meet their cultural needs such as information about South Asian foods. Short messages delivered in English are acceptable because family members often translate, but different formats may be needed, for example, videos. Face-to-face interaction is needed for those who do not use digital devices
	Perspectives From Underserved African Americans and Their Health Care Providers on the Development of a Diabetes Self-management Smartphone App: Qualitative Exploratory Study	Barber-Gumbs et al [60], 2021	78	T2DM	African-American individuals who had prediabetes or T2DM. Their family, friends, and health care providers were also included in the study	This study explored how a smartphone app can be used to improve diabetes self-management in terms of desired features and potential improvements to mock-up apps	United States	Forums, focus groups, and interviews	Participants were smartphone users	Participants mentioned that apps could help people who cannot easily access health care, specifically to provide diabetes education and self-management. Tracking diabetes care–related behavior and receiving feedback on progress was also mentioned as a way to increase engagement with self-management
Studies exploring the health benefit of DHIs
	Feasibility and Usability of a Text Message-Based Program for Diabetes Self-management in an Urban African-American Population	Dick et al [61], 2011	18	T2DM	African-American individuals diagnosed with T2DM	Personalized mHealth as an SMS text message to improve diabetes self-management	United States	Surveys and interviews	Participants must have owned a smartphone but received US $25 to cover expenses for an unlimited SMS text message plan	Participants increased their confidence in diabetes self-management, and missed medication doses decreased after the intervention
	Mobilizing Your Medications: An Automated Medication Reminder Application for Mobile Phones and Hypertension Medication Adherence in a High-Risk Urban Population	Patel et al [62], 2013	50	Prediagnosed hypertension and T2DM	Individuals with Medicaid as primary insurance, using at least 2 prescription medications for hypertension; most participants were diagnosed with T2DM, 96% were African-American	mHealth intervention as a mobile phone reminder for participants to take their medications; blood pressure and pharmacy refill records were assessed throughout the study	United States	Self-report questionnaires	Participants were given mobile phones preloaded with the “Pill Phone” app	Participants reported a high level of satisfaction with the intervention and increased medication adherence. Adherence, as measured by pharmacy recall data, showed a trend toward improvement, and it declined significantly after the intervention was discontinued
	Diabetes Island: Preliminary Impact of a Virtual World Self-care Educational Intervention for African Americans With Type 2 Diabetes	Ruggiero et al [63], 2014	41	T2DM	African-American individuals diagnosed with T2DM	An eHealth, virtual world intervention to improve diabetes self-care, clinical outcomes, and psychosocial factors and be seen as useful for patients with T2DM	United States	Self-report questionnaires	Participants were provided with a laptop that contained only the virtual program “Diabetes Island”	This intervention demonstrated participant acceptability; regular use; and promising outcomes, including improvements in BMI, diabetes-related distress, physical activity, dietary intake, and environmental barriers to self-care. The responses regarding the acceptability and usefulness of Diabetes Island were consistently positive
	A Digital Health Intervention to Lower Cardiovascular Risk: a Randomized Clinical Trial	Anand et al [51], 2016	343	CVD	South Asian individuals who were overweight or obese and had the ability to physically engage in study activities	eHealth to examine the MIf risk score in those who may not currently have CVD but are at risk of developing CVD owing to their ethnicity	Canada	Analysis of MI risk score	Participants were required to own a smartphone device	DHI use was not associated with a reduction in MI risk score after 12 months and was not influenced by knowledge of genetic risk status
	Adherence with Physical Activity Monitoring Wearable Devices in a Community-Based Population: Observations From the Washington, D.C., Cardiovascular Health and Needs Assessment	Yingling et al [55], 2017	99	CVD	African-American individuals who were at risk of CVD, as they were from communities of Washington, DC, with high obesity rates and low household incomes	mHealth (wristband) to track CVD health measures	United States	Self-reported questionnaires	Participants were given a physical activity–monitoring wristband	mHealth systems with a wearable device and local data collection hub may feasibly target resource-limited communities. No significant difference in CVD health factors were found between users and nonusers of the intervention
	A Smartphone App for Self-management of Heart Failure in Older African Americans: Feasibility and Usability Study	Heiney et al [64], 2020	12	CVD and heart failure	African-American individuals diagnosed with heart failure	Baseline and postintervention comparisons were made based on 4-week use of a health app to promote the self-management of heart failure	United States	Interviews and statistical analyses	N/A	The app did not significantly increase the quality of life but did show clinically relevant changes in heart failure self-care maintenance, management, and confidence
	Development and Evaluation of a Tailored Mobile Health Intervention to Improve Medication Adherence in Black Patients with Uncontrolled Hypertension and Type 2 Diabetes: Pilot Randomized Feasibility Trial	Schoenthaler et al [65], 2020	10	T2DM	Black individuals who had uncontrolled hypertension and T2DM and at least one CVD risk factor	mHealth intervention that includes surveys, interactive modules, and educational modules to improve medication adherence to reduce hypertension and manage T2DM	United States	Interviews and self-report questionnaires	N/A	After a 3-month mHealth intervention, medication adherence improved, but there were no significant decreases in systolic blood pressure and HbA1cg (average blood sugar levels). High acceptability of mHealth intervention
	Results of a Culturally Tailored Smartphone-Delivered Physical Activity Intervention Among Midlife African American Women: Feasibility Trial	Joseph et al [56], 2021	20	CVD	African-American females who had a BMI ≥30 kg/m2 and did ≤60 minutes of moderate-to vigorous-intensity physical activity per week	4-month physical activity intervention to increase physical activity including the use of an app, Fitbit, and SMS text messages	United States	Focus groups and tracking of Fitbit wear and progress	Participants were provided with a Fitbit Alta HR for the study	Participants increased moderate-to-vigorous physical activity per week. Of the 15 participants who completed the satisfaction survey, 14 (93%) indicated that they would recommend the intervention to a friend. Social support could improve the intervention

^aDHI: digital health intervention.

^bCVD: cardiovascular disease.

^cmHealth: mobile health.

^dT2DM: type 2 diabetes.

^eN/A: not applicable.

^fMI: myocardial infarction.

^gHbA_1c: hemoglobin A_1c.