A Smartphone-Guided Digital Health Application for Hypertension

The Randomized Controlled HELP Trial

Background: Hypertension is a significant risk factor for cardiovascular disease development. Current guidelines recommend a combination of medication and lifestyle modifications, particularly with regard to diet, exercise, blood pressure monitoring, and therapy adherence. To support this, the digital health application “Vantis Bluthochdruck” (Vantis app) was developed.

Methods: A prospective trial in 98 patients with uncontrolled hypertension at seven German centers tested whether the Vantis app lowers systolic blood pressure. Patients were randomized 1:1 to the app or standard care, with investigators blinded to group allocation at baseline. The primary endpoint was systolic blood pressure after 13 weeks, and the secondary endpoints were therapy adherence, diastolic blood pressure, resting heart rate, body mass index, and unplanned medical visits. The study is registered under DRKS00031923.

Results: The intervention group showed a significantly greater reduction in the primary endpoint, systolic blood pressure, than the control group (difference 5.5 mmHg, 95% confidence interval [1.3; 9.8]; p = 0.011). Systolic blood pressure fell from 151.4 mmHg [149.1; 153.8] to 144.3 mmHg [141.2; 147.3] in the control group and from 152.5 mmHg [149.8; 155.2] to 140.1 mmHg [136.7; 143.5] in the intervention group. Patients in the intervention group exhibited higher therapy adherence with no differences in other secondary endpoints. No app-related adverse events were reported.

Conclusion: The study indicates that the tested digital health application lowers systolic blood pressure in hypertensive patients and increases guideline adherence.

Cite this as: Zietzer A, Düsing P, Brokamp F, Schäfer S, Stieber F, Wilhelm K, Zgouras D, Schirmer SH: A smartphone-guided digital health application for hypertension: The randomized controlled HELP trial. Dtsch Arztebl Int 2025; 122: 292–7. DOI: 10.3238/arztebl.m2025.0066

Arterial hypertension is an important cardiovascular risk factor, leading to significant mortality and a relevant burden on the healthcare system (1). The pathophysiological origin of hypertension is multifactorial and involves environmental, behavioral, and genetic factors affecting multiple organ systems such as the kidneys, the cardiovascular system, and the central nervous system (2). Lowering systolic blood pressure is a key treatment goal for patients with hypertension and is explicitly recommended by German national guidelines and the European Society of Cardiology (ESC) guidelines (3, 4).

Due to the multifactorial nature of hypertension, with behavioral factors playing a crucial role, a comprehensive lifestyle modification is recommended at the outset of treatment for patients newly diagnosed with hypertension (defined as blood pressure > 140/90 mmHg) or elevated blood pressure (defined as blood pressure 120–139/70–89 mmHg) This recommendation remains a cornerstone of any antihypertensive intervention (3). Drug treatment should be initiated if hypertension persists after comprehensive lifestyle modification.

The key challenges in managing blood pressure include low adherence to treatment, limited compliance with lifestyle recommendations, and inadequate behavioral change (5). As a result, several guidelines offer evidence-based recommendations to improve adherence and lifestyle management (3, 6, 7). Physicians are encouraged to address these concerns during regular clinical visits. However, consistent implementation of this advice is difficult due to the long intervals between appointments and time constraints during the visits. Digital interventions could play an important role in this regard. Interestingly, the ESC guidelines on coronary artery disease give a class I recommendation (the strongest possible recommendation) in favor of the treatment of hypertension in the context of coronary artery disease with digital interventions, based on a variety of heterogeneous approaches such as text messages, interactive voice response systems, and smartphone apps (7, 8). While the German national guidelines are more conservative, with an open recommendation (“can be considered”), the ESC guideline on hypertension abstains from an explicit recommendation (3, 4).

Overall, evidence for digital interventions is sparse and is rarely based on randomized controlled trials. In a Korean cohort of patients with hypertension, Yun et al. recently reported that significant improvements in cardiovascular risk factors were achieved by 3 months’ use of a digital program in a randomized controlled trial (9). Conversely, the MyHeartMate study, a randomized controlled trial conducted in Australia, found no significant improvements in risk factors or lifestyle behavior after 6 months of mobile app intervention in 390 coronary artery disease patients (10). There are currently only limited widely available and thoroughly investigated digital therapy options focusing on lifestyle interventions for the treatment of high blood pressure.

The objective of the HELP study was therefore to investigate the effectiveness of the Vantis blood pressure app in lowering systolic blood pressure in patients with hypertension.

Methods

The HELP study was conducted as a prospective, randomized, controlled trial with a 1:1 allocation ratio in a parallel group design at seven centers in Germany. The participating study centers were primary care and cardiology offices. The study centers were given 300 euro per patient, and each participant received 50 euro, intended mainly as reimbursement of travel costs for all visits. All patients gave written informed consent prior to inclusion in the study.

The intervention group received the Vantis app in addition to standard care for 13 weeks. The app offers support in areas such as nutrition, physical activity, medication adherence, blood pressure measurement, smoking cessation, and stress management according to the ESH guidelines (11). The Vantis app is an approved, CE-certified medical device according to the European Medical Device Regulation. Additionally, a compatible blood pressure monitor was provided in both groups. Standard care included the continuation of existing treatment measures, especially the intake of medications, adjusted as needed by the treating physician. A detailed description of a sister app for the indication coronary artery disease and its functions has been published (12, 13). The control group received standard care for the same 13-week period.

The inclusion visits and data collection were conducted in a blinded manner. Randomization took place in the week following inclusion, with a 1:1 ratio. Randomization was carried out in blocks of four for each study center. During the inclusion visit and baseline assessment, the investigator and the practice team remained blinded. At the final visit, the patients and the study centers were aware of the group allocation.

The study included patients aged 18 years or older diagnosed with hypertension (ICD-10: I10–I13) and blood pressure above 139 mmHg at inclusion. Exclusion criteria were factors such as not having a compatible smartphone, lack of language proficiency, participation in another clinical trial, or a critical or unstable state of health. The primary endpoint of the study was the reduction in systolic blood pressure after 13 weeks in the intervention and control groups. Secondary endpoints, including diastolic blood pressure and resting heart rate, were also measured, with blood pressure measured using standardized oscillometric techniques under specific conditions with rest phases. An extended account of the methods including a detailed description of the functions of the Vantis app, can be found in the eMethods.

Results

Characteristics of the study participants

A total of n = 115 patients were screened, of whom 98 were randomized. Four patients had not had protocol-compliant blood pressure measurement, and 13 patients withdrew their consent before randomization. All 98 patients were included in the intention-to-treat (ITT) analysis. Of these, 88 patients completed the study according to the protocol and were included in the per-protocol (PP) analysis. The overall drop-out rate was 10%. Four of the 49 patients in the intervention group dropped out (8%), as did six of the 49 patients in the control group (12%) (Figure 1). The average age was 54.8 years, 74% of the patients were male, and the average body mass index (BMI) was 30.4 kg/m². Smokers made up 12% of the patients (Table 1).

Figure 1

Enrolment diagram of the HELP study

Table 1

Characteristics of the study population

The two groups were similar in their medical history, although there were 12% more cases of lipid metabolism disorders in the intervention group and 6% more cases of heart failure and chronic obstructive pulmonary disease (COPD) in the control group. The control group had a higher rate of blood pressure medication at the start of the study (intervention 65% versus control 73%) and more intensive adjustment of medication during the study (intervention 8% versus control 22%). The average systolic blood pressure was 152.0 mmHg (± 8.9 mmHg), while the diastolic blood pressure was 92.9 mmHg (± 9.5 mmHg). The patient cohorts were comparable overall.

Primary endpoint

The ITT analysis showed that reduction of systolic blood pressure was significantly greater in the intervention group, with a difference of 5.5 mmHg [1.3; 9.8] (p = 0.011) in the analysis of covariance (ANCOVA), correcting for baseline blood pressure and medication. Interestingly, both groups showed a reduction in systolic blood pressure over the course of the study: from 151.4 mmHg [149.1; 153.8] to 144.3 mmHg [141.2; 147.3] in the control group and from 152.5 mmHg [149.8; 155.2] to 140.1 mmHg [136.7; 143.5] in the intervention group (Figure 2, eTable 1). In the PP analysis, the difference was 5.5 mmHg [0.7; 10.3] in the ANCOVA (p = 0.026). The results remained robust when using univariate imputation: 5.8 mmHg [1.41; 10.09].

Figure 2

Primary endpoint: systolic blood pressure

eTable 1

Interaction analyses and subgroups

Secondary endpoints

The number of recorded blood pressure measurements in the last 14 days before the final visit increased significantly in the intervention group, by an average of 7.0 [5.2; 8.9] measurements more than in the control group. Treatment adherence, measured using the SC-HI questionnaire, improved by 0.14 [0.09; 0.19] points, on a scale of 0 to 1, in the treatment group compared with the control group in the ITT set. These results were also confirmed in the PP analysis. No differences were found regarding diastolic blood pressure, resting heart rate, BMI (Table 2), or unplanned medical visits due to cardiovascular symptoms (two in each group).

Table 2

Secondary endpoints

Post-hoc analyses

The interaction analyses for app usage, sex, age, and BMI confirmed the superiority of the Vantis app, with differences of 5.4 mmHg corrected for app usage, 6.7 mmHg corrected for BMI, 7.5 mmHg corrected for sex, and 3.6 mmHg corrected for age. Male and younger patients thus seemed to have lesser improvement (eTable 1).

The intervention group reported using the Vantis app for an average of 11.3 days during the 14-day period before visit 1 (n = 49, with the four drop-outs counted as 0 days). At baseline, blood pressure medication was less common in the intervention group than in the control group and involved fewer substances. During the study, blood pressure medication was more frequently intensified in the control group (eTable 2, eTable 3). The results of sex-based subgroup analysis indicate that women achieved a greater reduction in blood pressure than men. In the female subgroup, the difference between the intervention and control groups was 7.5 mmHg, compared with 5.2 mmHg in the overall ITT population.

eTable 2

Medication at study inclusion

eTable 3

Medication changes

The intervention group had numerically more adverse events, mainly due to three additional reported cases of upper respiratory tract infection. Three adverse events concerning the heart or kidney were reported, two of which occurred in the control group and one in the intervention group. Hypotension-related adverse effects such as dizziness, headache, or syncope were not reported. There was one serious adverse event in the intervention group, an aortic aneurysm with dissection. None of the events were causally linked to the use of the Vantis app (Table 3).

Table 3

Safety-related endpoints

Discussion

In this article we report that a smartphone-based digital health application can effectively lead to lower systolic blood pressure levels in patients with previously uncontrolled hypertension. Blood pressure reduction was significantly greater in the intervention group than in the control group, whose patients received only standard care.

The Vantis app reduced the systolic blood pressure by 5.5 mmHg in comparison with the control group. A comprehensive meta-analysis involving 147 studies and 464 000 patients showed that blood pressure-lowering medications can reduce systolic blood pressure by an average of 9.1 mmHg from a baseline value of 154 mmHg (14). This included various groups of medications such as thiazides, β-blockers, ACE inhibitors, angiotensin receptor blockers, and calcium channel blockers, all of which are similarly effective. Although the effect of the 13-week intervention was considerably lower than that of drug treatment, a clinically meaningful reduction in blood pressure could be achieved with the lifestyle modifications suggested by the Vantis app.

The reduction of systolic blood pressure we observed in our control group is comparable with previously reported results: A meta-analysis of 52 studies with 7451 patients shows that placebo effects can reduce systolic blood pressure by 5.9 mmHg (15). This can be explained by the Hawthorne effect and related psychological effects. Hence a control group, as in our study design, is an absolute necessity. Furthermore, our study centers were allowed to adjust blood pressure medication during the study. This occurred numerically more often in the control group and may have contributed to the lowering of blood pressure in that group (eTable 2, eTable 3).

The secondary endpoints and usage analyses of the application suggest that the improvement in systolic blood pressure values in the intervention group is linked to the intervention. The adherence of the intervention group improved significantly, as confirmed by the SC-HI questionnaire. These findings clearly show that the application not only has a positive impact on blood pressure but also promotes the implementation of guideline-based treatment measures in daily life. Even after 3 months, the application was used by the treatment group on 11.3 out of 14 days, and the treatment group showed statistically significant and clinically relevant higher treatment adherence, as well as a significantly greater number of days with measured and documented blood pressure.

The study has certain limitations, including its open design and the inability to blind participants due to the nature of the intervention involving app usage. Despite the small sample size, we observed a significant reduction in systolic blood pressure with the intervention over a relatively short period of 13 weeks. However, because the digital health application is a multifactorial intervention, the study design does not allow us to determine which specific component contributed to the blood pressure reduction. The relatively short 13-week observation time has to be considered a limitation in itself. Although blood pressure medication was less common at baseline in the intervention group, intensification occurred more often in the control group. A bias caused by stronger antihypertensive drug regimes in the intervention group is thus unlikely.

The strengths of the study include its prospective and randomized design. The digital health application, based on the guidelines of the European Society of Cardiology, takes a multidisciplinary approach to lifestyle management, addressing multiple risk factors while encouraging active patient involvement in secondary prevention strategies. Furthermore, the patients in the two groups were comparable. While changes in medication could potentially act as a confounder, such adjustments occurred more frequently in the control group.

Conclusion

With the HELP study, we have shown that integrating the smartphone-based digital health application into standard care has a beneficial impact on lowering blood pressure in individuals with uncontrolled hypertension. This study highlights a significant advance in digital primary cardiovascular prevention. Further studies are needed to investigate the influence of such a digital intervention on further cardiovascular risk factors and long-term outcomes.

Funding

The study present here was funded by Vantis GmbH, a developer of digital health applications. Extraction of the data from the CRF was accomplished under the supervision of the study group, whose members had full access to the raw data. The analysis and interpretation were entirely the responsibility of the study group, with support provided by Vantis GmbH. The study centers and the participating patients received payments from Vantis GmbH.

Data sharing

The underlying participant data will not be made universally available.

Conflict of interest statement

AZ has received a lecture fee from Vantis GmbH.

FB, SS, FS, KW, DZ, and SHS have received financial compensation from Vantis GmbH for each participant contributed to the HELP study.

AZ, PD, SS, and SHS have received financial compensation from Vantis GmbH for each participant contributed to the CHANGE study.

DZ has received payments from Vantis GmbH for consultation and training of field sales staff.

Manuscript received on 17 October 2024, revised version accepted on 1 April 2025.

Corresponding author
PD Dr. med. Andreas Zietzer

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