AOK digital heart health: promoting and inhibiting factors of digital preventive interventions

The National Care Guideline for Hypertension recommends regular physical activity for patients suffering from hypertension (German Medical Association et al. 2023: 21). This raises the central question of which factors are responsible for the success of digital preventive interventions that positively influence heart health. The following evaluation results of the model project "AOK Heart Health Digital" are intended to contribute to identifying factors that have a positive effect on health behavior, health literacy, and self-management/disease management, and which can promote or hinder the (long-term) use of such interventions.

methodology

Intervention AOK Heart Health Digital
>> As part of the "AOK Digital Heart Health" project, patients aged 20 to 75 suffering from hypertension-related complications according to ICD I10-I10.91 were given the opportunity to participate. The project comprised three components: 1) the health app "myHeartHealth," 2) a blood pressure monitor (Tel-O-Graph), and 3) telephone consultation with a sports scientist. The main goal was to lower participants' blood pressure by, among other things, promoting their physical activity. At the start of the program, a telephone conversation was held with a sports scientist to identify current fitness levels, exercise preferences, and barriers. Based on this, a personalized training plan, including both strength and endurance exercises, was created and stored in the app. The app contained a selection of videos featuring various strength exercises with and without equipment (e.g., dumbbells, balls) for different fitness levels. The range of difficulties varied and included activities such as getting out of a sitting position or performing a one-arm push-up. There was also the option to take part in an endurance program in which participants could perform various activities (e.g., cycling, endurance running, tempo running, walking, strolling). They wore a chest strap through which the measured heart rate values were transmitted to the app. The app also included a "digital coach" who gave acoustic instructions during training to ensure an optimal heart rate range. In addition to the heart rate measurement, the app documented other data (e.g., elevation gain, speed, calorie consumption, distance traveled). In terms of individual progress, in addition to the initial telephone consultation, further telephone calls were held after two, six, and ten weeks to individually adapt the training plan. Participants had the opportunity to measure their blood pressure twice a day using a measuring device provided. The components were provided for a planned period of 52 weeks (starting on August 1, 2021), which was extended to 183 weeks (ending on January 31, 2025) due to the COVID-19 pandemic. A total of 20 medical practices participated in the pilot project, with the help of these practices and additional AOK events, 223 participants (29 dropouts) were enrolled in the program.

Study design and sample
The evaluation was conducted from the participants' perspective. Self-assessments were collected using questionnaires via the online tool "SoSci Survey." The online survey was conducted anonymously and in strict compliance with data protection regulations. Following a pretest, participants were provided with an online link after 1) 5 weeks, 2) 10 weeks, and 3) 20 weeks of program participation. Response rates were exceptionally high, ranging from 25.7% to 37.5% (Wave 1: 169 links and 62 participants, Wave 2: 160 links and 60 participants, Wave 3: 144 links and 37 participants). The descriptive analysis was conducted using SPSS 29. The proportion of male participants was slightly higher than the proportion of female participants (56.0% female, 0.6% diverse, 0.6% not specified). Most participants were between 50 and 59 years old (22.6% 50 to 54 years, 23.9% 55 to 59 years, 15.1% 60 to 64 years, and 18.2% 65 to 69 years). Outside this age group, 3.1% were aged 25 to 29, 1.9% were aged 35 to 39, 5.0% were aged 40 to 44, 5.7% were aged 45 to 49, and 4.4% were aged 70 to 75. The vast majority were married (78.0% of respondents) or living in a partnership. 10.1% of the respondents were single, 8.8% were divorced, and 5.1% were widowed. The sociocultural background is characterized by an above-average educational background, with 27.7% having a secondary school diploma, 22.0% a university degree, and 19.5% having a university entrance qualification or Abitur. It should also be noted that the majority of the test subjects have many years of experience with the disease; for 28.91%, the diagnosis was more than 10 years ago.
Results
a.) General findings
Overall, the project achieved very high levels of satisfaction. The majority of participants would like to continue participating in the program after the project ends and would recommend the project to others (Wave 1: 75.8%, Wave 2: 81.4%, Wave 3: 94.6%). Satisfaction increases with the duration of participation. This suggests an increased perception of added value. 69.5% (Wave 1) to 81.0% (Wave 3) rated the program overall as "somewhat useful" to "very useful."

b.) Findings on program participation
The majority of enrollments (35.5%, 35.5%, 35.7%, 35.9 ...

c.) Findings regarding the program elements
The telephone consultation and the delivery of the blood pressure monitor proved to be by far the most important perceived support (Fig. 1). The telephone consultation was perceived as very motivating by more than half of the participants (59, 11, 30), regardless of gender. With regard to the app, it should be noted that older people aged 60 and over, in particular, found it less helpful than younger participants. The blood pressure monitor was used most frequently, followed by the MyHeartHealth app, which was used several times per week. The documentation function is the most frequently used functionality of the app (35, 4, 30), which was perceived as very motivating by 30, 21, 30. The intensity of app use decreased over the course of the project. These findings are consistent with other scientific findings (Lee et al. 2018: 4; Rasche et al. 2018: 5), which demonstrate that app use decreases significantly over time. No gender or educational differences were observed regarding app usage. The personal component (telephone counseling) can be considered a key success factor of the project, as has also been demonstrated in other interventions (Cheah et al. 2024; Choo et al. 2023; Wong et al. 2023).
d.) Findings regarding health-related improvements
An improvement was observed in the area of subjective self-management/illness management, particularly with regard to knowledge of one's own medical condition. Furthermore, an increase in endurance, general health, and quality of life was reported among participants. Approximately 15% and 16% of participants, respectively, reported that their endurance and health had improved. Self-management also improved. The comparison between waves 1 and 2 (and 3) shows that self-management/illness management, particularly knowledge of one's own medical condition, improved. While improved endurance and fitness were perceived as the most important benefits by both sexes, women also perceived regular medication intake and increased strength. It was also found that the perceived benefit increased with the duration of program participation. The increased health literacy also had a positive influence on attitudes towards the disease. Increased health literacy proved particularly beneficial for the recognition of personal responsibility with regard to individual health behavior, the identification of potentially harmful habits, and the promotion of a positive attitude towards the disease (Fig. 2).
e.) Findings regarding hindering and facilitating factors
It was found that participants found telephone counseling particularly supportive. An open question about supportive factors (Table 1) clearly shows that personal counseling and support were mentioned most frequently. Problems and difficulties in using the MyHeartHealth app or chest strap were particularly cited as barriers. These technical barriers posed a particular challenge for older people. On the behavioral level, lack of time (54.11 TP3T), physical limitations (24.61 TP3T), listlessness (13.21 TP3T), and lack of motivation (13.21 TP3T) were identified as the biggest barriers, which "somewhat apply" and "completely apply." With increasing participation duration, one-third of participants viewed the training sessions themselves as easy and did not pose a barrier.
Limitation

The following limitations must be considered when interpreting the results. Due to the extension of the project, participants were surveyed and started at different times, which could have resulted in external factors (e.g., the COVID-19 pandemic, lockdown). These factors could have influenced participants' behavior and thus led to biases in the collected data. The app was optimized during the survey period. These improvements could have influenced user behavior and thus the survey results. The small sample size and the decrease in samples from each wave limit the significance of the temporal trends. The changed sample size within the waves and the composition of the sample could have been influenced by changes in participant recruitment during the study. Despite all these limitations, the study provides important impetus for future digital interventions for heart health.
Conclusion and recommendations for action
Overall, recent studies (Rowland et al. 2024) demonstrating that digital health interventions can make an effective contribution to improving cardiorespiratory fitness can be confirmed. However, for the acceptance of such interventions, it is necessary for physicians to be better informed about the potential of behavioral support apps. Physicians play a key role in the acceptance and trust of health apps (Jiang/Lau 2023: 4). In line with previous research (Cheah et al. 2024; Choo et al. 2023; Wong et al. 2023), given the positive feedback on telephone counseling, interventions should always be designed in a hybrid format. The personal component of motivation is important in such measures. Participants also expressed a desire to engage with others. An app community or the option of low-threshold exchange via video conferencing could contribute to increasing motivation and use of the app itself. Participants should also be taught methods to strengthen self-motivation, develop habits, and prevent relapse. Psychological aspects (reducing anxiety, feelings of guilt, etc.) should be taken into account, for example, through short video sequences or existing content (from statutory health insurance providers, e.g., YouTube channels). The app content should preferably be implemented with and by members of the same age group to ensure better identification with the target group. Furthermore, the physical activities should be tailored to the needs of the participants and consider other behavioral aspects (e.g., nutrition, stress management) to promote holistic heart health. This also includes reminders (e.g., optional push notifications regarding medication intake or blood pressure measurement). Such push notifications, or gentle nudges and encouragement for health-related behavioral changes, are crucial to counteracting listlessness and lack of motivation. Behavioral aspects (e.g., tips for establishing health-promoting habits in everyday life) in particular represent success factors, while technical barriers due to the involvement of potential (older) participants in the development of such projects (e.g., app redesign, video tutorials) are crucial. High digital health literacy can be considered a key factor for exploiting the potential of the digital transformation of the healthcare system (cf. Dratva et al. 2024). For this reason, the measures required by law under Section 20k of the Social Code (SGB V) to increase the digital health literacy of statutory health insurance funds are particularly relevant to ensure the acceptance and positive impact of digital prevention interventions. People from lower educational and social backgrounds, in particular, have a high need because, on the one hand, they have particularly low digital health literacy (Schaeffer et al. 2021) and, on the other hand, they have the greatest potential for prevention due to their age.

background
In 2022, around 30% of the German population (29,141% women, 30,821% men) were affected by high blood pressure or (arterial) hypertension (WIdO 2024). This high proportion of people with high blood pressure is associated with an increased risk of secondary diseases, including cardiovascular diseases, strokes, and kidney damage (WIdO 2024). In 2023, most deaths (348,312) were attributable to cardiovascular diseases (Federal Statistical Office 2024). Against this background, preventive interventions to reduce high blood pressure are of great relevance. In particular, mHealth interventions to promote self-management of hypertension (e.g., mobile phones, patient monitoring devices, wireless devices) (Li et al. 2020: 2) are suitable for improving medication management and self-efficacy in those affected. Furthermore, digital prevention interventions (e.g., health apps) can promote a healthy lifestyle, improve knowledge about hypertension (Israfil et al. 2022: 233; Li et al. 2020: 10), and positively influence health behaviors (Gray et al. 2022: p. 15). Regarding health behaviors, it should be noted that physical inactivity is one of the most common risk factors for cardiovascular disease (German Medical Association et al. 2023: 7).