https://mhealth.jmir.org/issue/feed 2024-01-05T10:15:04-05:00 JMIR Publications editor@jmir.org Open Journal Systems Unless stated otherwise, all articles are open-access distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work ("first published in JMIR mHealth and uHealth...") is properly cited with original URL and bibliographic citation information. The complete bibliographic information, a link to the original publication on http://mhealth.jmir.org/, as well as this copyright and license information must be included. JMIR mhealth and uhealth is a new journal focussing on mobile and ubiquitous health technologies, including smartphones, augmented reality (Google Glasses), intelligent domestic devices, implantable devices, and other technologies designed to maintain health and improve life. https://mhealth.jmir.org/2026/1/e102863 2026-09-25T17:00:19-04:00 Clara Sofia Heil Shobna Sawry Susanne Frennert Jean Le Roux Pascalia Ozida Munyewende Sibusiso Mkwananzi Ijeoma Solarin Perkins Watambwa Koen van der Sanden Isabelle Lange Günter Alce Veronique Filippi Stanley Luchters Chuansi Gao

<strong>Background:</strong> Early warning systems (EWS) have the potential to reduce heat-related health risks, yet few are designed specifically for vulnerable populations. Pregnant women and infants, often cared for by postpartum women, are particularly susceptible to heat-related illnesses. The MotherHeat Alert mobile app is a heat EWS specifically developed for pregnant and postpartum women. <strong>Objective:</strong> This study aimed to assess the usability and effectiveness of the MotherHeat Alert in the Tshwane District, South Africa. <strong>Methods:</strong> This prospective observational evaluation study included a cohort of 201 participants (100 pregnant and 101 postpartum) who were followed over a 6-month period. In addition, a questionnaire was administered at 3 time points (baseline, midpoint, and end point) to collect self-reported information on health, living situation, and heat exposure, among other parameters. Usability was evaluated in the end point questionnaire through a validated Post-Study System Usability Questionnaire (PSSUQ), using descriptive statistics. Effectiveness was assessed through changes in self-reported heat-protective behaviors between baseline, midpoint, and end point, as well as through end point assessments of heat-health knowledge increase and self-reported behavior change attributable to the intervention. Generalized estimating equations were used to analyze repeated measures of heat-protective behaviors, while descriptive statistics were used to summarize end point–reported knowledge gains and behavior change. <strong>Results:</strong> Usability scores indicated high overall usability, with mean PSSUQ scores of 1.76 (SD 0.60) among pregnant women and 1.37 (SD 0.45) among postpartum women. Similar patterns were observed across most PSSUQ subscales, including system usefulness, interface quality, and information quality. Most self-reported behavior change due to alerts received through the app was rated as large to very large by the pregnant women (47/70, 67%) and postpartum women (68/82, 83%). Nevertheless, comparing behavior change at baseline and end point mainly highlighted a decrease in protective behavior in both pregnant and postpartum cohorts. Self-reported knowledge increase among pregnant and postpartum women was reported as large to very large following the use of the EWS (55/70, 79% and 72/82, 88%, respectively). Importantly, however, attrition was substantial, particularly among pregnant participants, reaching 30% (30/100) in the pregnant cohort and 19% (19/101) in the postpartum cohort by end point. <strong>Conclusions:</strong> The MotherHeat Alert app demonstrated positive outcomes in usability. Effectiveness showed conflicting results, with positive self-reports on behavior change and knowledge increase, yet a decrease in protective heat behaviors when comparing baseline and midpoint with end point results, likely due to seasonality effects. Nevertheless, these findings highlight the potential of tailored EWS to support heat adaptation among pregnant and postpartum populations. Successful implementation and scalability require careful consideration of contextual factors, further assessment of long-term usability and integration into existing health infrastructure.

2026-09-25T17:00:19-04:00 https://mhealth.jmir.org/2026/1/e89548 2026-09-24T16:30:12-04:00 Shiyu Yan Jinlang Lyu Chunjie Yin Wenhao Li Yan Li Hai-jun Wang

Background: Childhood obesity remains a major public health challenge. Mobile health (mHealth) interventions offer a scalable approach to support behavior change, but their effectiveness may depend on participant adherence. While both caregiver and child adherence are important, few studies have jointly examined caregiver app-use adherence and child behavioral adherence within digital obesity interventions. Objective: This study aimed to evaluate the independent and joint associations of caregiver app-use adherence and child behavioral adherence with obesity-related outcomes in a school-based mHealth intervention. Methods: We conducted a secondary analysis of 684 child-caregiver dyads in the intervention arm of the diet, exercise, and cardiovascular health—children cluster-randomized trial, implemented across 3 socioeconomically diverse regions in China. Caregiver app-use adherence was measured using app-recorded app-use frequency and total usage duration. Child behavioral adherence was assessed through weekly behavior monitoring scores covering diet, screen time, and physical activity. Linear mixed models estimated associations between adherence levels and changes in anthropometric and physical fitness outcomes over 9 months. Results: Higher caregiver app-use frequency and duration were both significantly associated with reductions in children’s obesity-related indicators, such as BMI (β=−0.19; =.005), BMI -score (β=−0.08; =.006), and body fat percentage (BFP) (β=−0.70; =.005) for frequency. Greater child behavioral adherence was associated with lower BFP (β=−0.63; =.01) and better physical fitness, including shorter shuttle run time (β=−3.63; <.001) and longer standing long jump distance (β=2.88; =.005). App-use frequency and duration showed a significant interaction for rope-skipping performance (=.05). In joint adherence analyses, children in the high caregiver-high child adherence group showed the most favorable changes, including lower BMI (β=−0.22; =.02), lower BFP (β=−1.18 percentage points; =.001), and 7.45 additional rope-skipping repetitions (=.003), compared with the low caregiver-low child adherence group. Conclusions: In this secondary analysis of an mHealth app-assisted childhood obesity intervention, higher caregiver app-use adherence and child behavioral adherence were associated with more favorable changes in weight status and physical fitness. These findings underscore the importance of coengagement in digital health programs and highlight the potential of app-supported, family-engaged strategies for childhood obesity prevention. Trial Registration: ClinicalTrials.gov. NCT03665857; http://clinicaltrials.gov/study/NCT03665857 International Registered Report Identifier (IRRID): RR2-10.1136/bmjopen-2018-027902

2026-09-24T16:30:12-04:00 https://mhealth.jmir.org/2026/1/e92481 2026-09-23T15:30:12-04:00 Xiaojiao Yuan Xi Zhao Meng Zhang Yurou Duan Yizhong Shui

Background: Family caregivers of children with disabilities frequently experience high levels of stress and psychological burden. Digital support platforms offer accessible channels for information and emotional support, but their long-term use patterns remain underexplored. Objective: This study explored the longitudinal patterns of digital support platform use among family caregivers in China, with a focus on factors potentially associated with initial adoption and continued engagement. Methods: A 3-wave survey was conducted over 6 months with 240 primary caregivers of children with disabilities in China. A 2-part latent growth curve model was used to jointly model adoption (use vs nonuse) and engagement (use frequency among users). Key demographic, psychosocial, and child-related factors were examined as predictors. Results: Adoption increased significantly over time (probit slope=0.54, SE 0.16; =.001). Higher baseline adoption was associated with male sex (β=.19; =.02), higher education (β=.42; <.001), better socioeconomic status (β=.26; =.001), stronger social support (β=.17; =.03), and more depressive symptoms (β=.18; =.02). Among users, engagement frequency showed no significant average change over time (mean slope=–0.07, SE 0.07; =.31). Higher initial engagement was associated with higher education (β=.36; <.001) and social support (β=.20; =.04). Better child rehabilitation status was associated with steeper declines in engagement over time (β=–.28; =.03). Conclusions: Adoption and engagement showed distinct longitudinal patterns and were associated with different factors. The findings suggest that reducing digital barriers and aligning support with caregivers’ evolving needs may be relevant to facilitating platform use and sustained engagement. This study offers a theory-informed lens for describing digital support platform use among vulnerable caregiving populations.

2026-09-23T15:30:12-04:00 https://mhealth.jmir.org/2026/1/e84076 2026-09-21T16:30:12-04:00 Eeva Rantala Mikko Valtanen Adil Umer Suvi Parikka Jussi Pihlajamäki Ilona Ruotsalainen Jaana Lindström

Background: Digital interventions provide a scalable approach to promote healthy lifestyles, but at-scale evidence of their effects and effect modifiers is limited—even scarcer for habit-based digital interventions, although habits are promising lifestyle intervention targets. Objective: We conducted a 1-group pre-post effect and effect modification assessment of a web-based app designed to support the formation of health-promoting lifestyle habits by exploring the relationship between objective app use and subjective changes in behavioral outcomes. Methods: Three-month app access was offered to a subsample of the population-based Healthy Finland survey participants aged 20-74 years via SMS text messaging or mail. The app provided personalized behavioral suggestions that translated evidence-based lifestyle guidelines into simple, repeatable actions (“habits”). Users could browse and select these habits, and report and monitor their performances. The assessment used app log data, questionnaires collected through the app at baseline and at 45 and 90 days, and background information obtained from the national population register and the Healthy Finland Survey. Linear mixed effects models explored the (1) associations between app use and changes in self-reported diet quality (Healthy Diet Index), physical activity (metabolic equivalent of task hours per week), and BMI, and (2) modification of these associations by baseline characteristics related to sociodemographics, health, lifestyle, and e-service use. App use measures comprised the percentage of app use days (ie, days with logins/days of follow-up×100) and the number of reported habit performances (total, diet-related, physical activity–related, and BMI-related). Results: Of 6975 invitees, 1282 (18.4%) accepted the invitation and 382 (5.5%; mean age 51, SD 15 y; women: n=263, 69%) completed the data collection required for the assessment. Over 90 days, the median percentage of app use days was 5.9% (IQR 3.3%‐11%), and the total number of reported habit performances was 22 (IQR 3‐68.5). A higher percentage of use days (by 10 percentage points) was associated with a 3.09 (95% CI 0.79‐5.39) metabolic equivalent of task hours per week greater increase in physical activity and a 1-unit higher logarithmic number of reported performances with a 0.51 (95% CI 0.07‐0.95) Healthy Diet Index point greater improvement in diet quality. Other associations between app use and outcomes were nonsignificant. Greater physical activity and a more positive attitude to e-services at baseline appeared to enhance the effect of app use on physical activity ( values <.05). The app received a median acceptability rating of 2.9 (IQR 2.4‐3.3, scale: 1‐4) and a median overall score of 7 (IQR 5‐8, scale: 0‐10). Conclusions: An inexpensive, low-intensity digital support for healthy habits could foster small beneficial lifestyle changes, but effects require user engagement and may depend on the individual. The findings warrant confirmation in more robust study designs and call for further research for identifying those most likely to benefit from such digital support.

2026-09-21T16:30:12-04:00 https://mhealth.jmir.org/2026/1/e92493 2026-09-21T11:30:12-04:00 Elke Warmerdam Lea-Marie Burger Bergita Ganse

Background: The timed up-and-go (TUG) test is a mobility-related functional task commonly performed in clinical practice for a variety of clinical applications. By instrumenting the TUG test with sensors, creating an instrumented TUG (iTUG), additional parameters can be extracted, which may add clinical value. Instrumented insoles are among the most promising wearable devices that are currently being explored for clinical purposes. Objective: The study aims to assess additional parameters obtained by instrumenting the TUG test with pressure-sensing insoles for monitoring fracture healing and to analyze whether these parameters reveal differences between patients with and without union of tibial or malleolar fractures. Methods: Patients with tibial or malleolar fractures and matched controls were enrolled. Patients’ TUG test data were collected as follows: (1) longitudinally—at 6 weeks, 3 months, and 6 months after surgery—and (2) cross-sectionally—at 6 months after surgery when patients were referred for nonunion treatment. All participants performed the TUG test using instrumented insoles. TUG tests were video-recorded and analyzed in terms of the time taken to complete each part of the TUG test (conventional TUG). The insole data-derived outcome measures were maximal force during sit-to-stand and stand-to-sit movements, stance time and stride time during walking, and asymmetry of the previously mentioned parameters (iTUG). Results: Twenty-seven patients with fracture, a similar number of healthy adults, and 9 patients with fracture nonunion were assessed. All TUG parameters improved throughout the healing process (all <.001). The greatest improvements were detected between 6 weeks and 3 months (all <.001). Among the classical TUG parameters, between 3 and 6 months, only the total TUG time, walking time, stand-to-sit time, and total number of steps significantly improved (=.004, =.01, =.03, and =.002). Based on the additional iTUG measures, 6 months after surgery, the loading of the injured side was reduced in patients compared with healthy controls during sit-to-stand and stand-to-sit movements (<.001). Six months after surgery, patients with fracture nonunion had significantly poorer performance in terms of all of the TUG test parameters, except for stance time, than patients with fracture union. Conclusions: This study indicates the potential for using functional outcomes to identify patients at risk of nonunion. Additional tasks and functional outcomes require further investigation. Trial Registration: German Clinical Trials Registry DRKS00025108; https://drks.de/search/en/trial/DRKS00025108

2026-09-21T11:30:12-04:00 https://mhealth.jmir.org/2026/1/e64278 2026-09-18T16:00:04-04:00 Xinghui Yan Afton L Hassett Jennifer F Waljee Mark W Newman Sun Young Park Rongqi Bei Noelle E Carlozzi

<strong>Background:</strong> Relaxation-based mobile health (mHealth) interventions hold strong potential to address perioperative anxiety and pain management in a scalable manner. However, there is limited research on how surgical patients engage with these interventions and what aspects may be most helpful. <strong>Objective:</strong> This study had 3 goals: (1) explore how users interact with a relaxation-based mHealth intervention during the perioperative period; (2) understand how user performance and perceptions relate to perceived benefits; and (3) identify design considerations to enhance user engagement and behavior change outcomes in mHealth interventions. <strong>Methods:</strong> We conducted a prospective longitudinal cohort, mixed methods study to evaluate user engagement with MiCarePath, a relaxation-based mHealth intervention. A total of 19 perioperative patients (mean age 41.3 years; 14/19, 74%, female) undergoing elective surgery and reporting sometimes-to-always anxiety were enrolled using 3 recruitment methods. Participants used the app from 10 days before surgery to 4 weeks after surgery. We collected quantitative data on video engagement metrics (eg, duration of watching, response rate to video prompts) and ecological momentary assessments of anxiety and pain. Concurrently, we conducted semistructured, data-prompted interviews at 3 time points to assess user perceptions. These data were integrated using descriptive statistics, repeated-measures ANOVA, and qualitative thematic analysis to examine the relationship between user performance and perceived benefits. <strong>Results:</strong> Eleven participants reported developing or improving relaxation-based self-management strategies (high benefit), whereas 8 reported little benefit from the intervention. The high-benefit group showed significantly greater total watching time (difference 223.8 minutes, 95% CI 95.54-366.46 minutes, <i>P</i>&lt;.001), higher adherence to video prompts (73.45% vs 34.60%, <i>P</i>&lt;.001), and greater perceived helpfulness of the content (79.80% vs 25.50%, <i>P</i>&lt;.001) compared with the low-benefit group. A significant group-by-time interaction effect was observed for engagement (<i>F</i>_1,17=17.02, <i>P</i>&lt;.001). No difference was observed in delay in response to video prompts. However, within each group, participant perceptions were not fully reflected in performance. Some participants in the high-benefit group showed decreased video watching after surgery but still reported feeling engaged with the intervention. Interview data revealed that “intentional use” behavior—where users actively seek content to manage symptoms independent of prompts—distinguished these participants. Those who developed intentional use were able to practice relaxation techniques without the app and resume app engagement following contextual disruptions. <strong>Conclusions:</strong> This study explored user engagement with a relaxation-based mHealth intervention for perioperative care, advancing the literature by integrating user perceptions and performance for digital anxiety and pain management. Results indicate that perceived benefit may not always be reflected in user performance. Intentional use emerges as a promising indicator of effective mHealth engagement in perioperative care. Future designs should aim to foster intentional use through features such as reflection prompts and adaptive notifications. Future work should also develop computational models to detect intentional use and evaluate adaptive interventions in larger cohorts.

2026-09-18T16:00:04-04:00 https://mhealth.jmir.org/2026/1/e84430 2026-09-17T16:30:03-04:00 Sarang Jang Aeree Sohn

Background: Walking is one of the most effective forms of physical activity; however, maintaining long-term engagement in digital step-counting interventions remains challenging. Objective: This study aimed to evaluate the effects of personalized message interventions integrating the Information-Motivation-Behavioral Skills (IMB) model and regulatory focus theory (RFT) on walking behavior. Methods: Participants were recruited offline through community advertisements containing a QR code that linked to an online sign-up form and were screened using an online baseline questionnaire by research staff, while all intervention delivery and outcome assessments were conducted via the WalkOn mobile app. A 12-week randomized controlled trial targeting 174 adults in Mapo-gu, Seoul, Korea, was conducted from April 1 to June 22, 2024. Of the 174 randomized participants, 141 (67 in the intervention group and 74 in the control group) engaged in the intervention. Both groups received incentives based on goal achievement and general health information, whereas the intervention group received weekly personalized messages provided by research staff according to midweek step-count performance. Primary outcomes included weekly goal achievement rates for the 25,000-step goal, step-count patterns, and consecutive 2-week goal achievement failure events. Analyses were conducted using generalized estimating equations (GEEs), linear mixed models (LMMs), and Cox proportional hazards models. Results: Of the 174 participants randomized, 141 (81%) engaged in the intervention and were included in the analyses (67 intervention; 74 control), while 33 participants did not participate after randomization. The overall 12-week mean goal achievement rate was 87% in the intervention group and 87% in the control group, with no significant difference between the groups (odds ratio [OR] 1.12, 95% CI 0.29-4.37; <i>P</i>=.87). Weekly step-count patterns also showed no significant differences (group × time interaction: estimate=–417; SE 09; <i>P</i>=.31). However, the risk of consecutive 2-week goal achievement failure events was significantly lower in the intervention group (hazard ratio [HR] 0.67, 95% CI 0.52-0.86; <i>P</i>=.002). The intervention group showed an approximately 33% lower likelihood of consecutive 2-week goal achievement failure events than the control group. Conclusions: Personalized message interventions did not show significant effects on overall step-count increase but were associated with a reduced risk of consecutive 2-week goal achievement failure events. These findings suggest that personalized messages may play an important role in improving behavior change sustainability and failure resilience. Incorporating personalized messaging strategies may enhance the effectiveness of digital health intervention design. Clinical Trial: Clinical Research Information Service (CRIS), Republic of Korea KCT0010966; https://tinyurl.com/3jeepxve

2026-09-17T16:30:03-04:00 https://mhealth.jmir.org/2026/1/e94732 2026-09-15T17:15:10-04:00 Frederick G B Goddard Jessica Garay Francisco Teixeira Neves Alexandra Ligeti Liudmila Zhaunova Manuela Abreu

Background: Approximately 2.5 billion adults worldwide were living with overweight or obesity as of 2022, highlighting the need for comprehensive weight management solutions. Digital nutrition platforms have emerged as an accessible solution that can be implemented at scale. Nutrium Care is an employer-sponsored program delivered via the Nutrium platform, facilitating dietitian-led nutrition counseling through consultations and in-app communication, while also enabling users to track food intake, water consumption, and physical activity. Objective: This study set out to characterize longitudinal weight changes among active users of the Nutrium Care program and estimate associations between program engagement and weight loss. Methods: This retrospective cohort study analyzed deidentified data from adult users with overweight or obesity enrolled in the Nutrium Care program. Users were included if they were taking action to manage their weight and had at least 3 months of follow-up data available; these users were referred to as active users. The primary outcome was weight loss after 3 and 6 months, estimated using piecewise linear mixed-effects models. To estimate the association between engagement and weight loss, more- and less-engaged users were matched on sociodemographic characteristics. Engagement was defined by the number of dietitian appointments, days of active platform use, and logging of food, water intake, and physical exercise. Results: The study included 10,288 active users, predominantly female (n=6887, 66.9%) and aged 18 to 49 years (n=9741, 94.7%), who contributed a median of 6 (IQR 4‐9) months of data to the cohort. In the first 3 months, active users lost 2.0 kg (2.4% of baseline body weight; 95% CI 1.9-2.0 kg) on average, increasing to 2.3 kg (2.8%; 95% CI 2.2-2.4 kg) by 6 months. Higher program engagement was associated with more weight loss, with the strongest association estimated for at least 1 dietitian appointment every 2 months, corresponding to 0.8 kg (95% CI 0.7-1.0 kg) additional weight loss after 3 months. Conclusions: This retrospective cohort study addresses a critical research gap in hybrid nutrition interventions integrating professional dietitian support with an employer-sponsored digital nutrition program. Active users achieved weight loss, and regular contact with a dietitian was the strongest engagement factor associated with improved outcomes, supporting the potential role of professional support in digital weight management programs.

2026-09-15T17:15:10-04:00 https://mhealth.jmir.org/2026/1/e73259 2026-09-14T17:30:09-04:00 Ruth Ruscheweyh Lars Neeb Bianca Raffaelli Torsten Kraya Tobias Freilinger Thomas Dresler Gudrun Gossrau Tim Patrick Jürgens Victoria Ruschil Jörg Scheidt Yannic Siebenhaar

Background: The use of electronic headache diaries via smartphone apps has several advantages over paper and pencil diaries. Still, adherence is not always satisfactory. One potential strategy to improve adherence is the implementation of daily reminders, but their effect remains uncertain. Objective: The DMKG-App (the headache diary app of the German Migraine and Headache Society, DMKG) sends daily reminders to encourage user adherence. Due to a technical problem, reminders failed for a 14-day period in early 2023. This provided a unique opportunity to evaluate the effect of daily reminders on adherence to the headache diary in the form of a retrospective longitudinal observational cohort study. Methods: The failure period was compared to 14-day prefailure and postfailure periods and to corresponding periods of the previous year. We evaluated effects on the number of daily entries, delay to make the daily entry, and attrition rate, using ANOVA and logistic regression (α<.05). The effect of age, gender, headache frequency, and previous adherence was investigated using interaction analysis. Results: The DMKG-App had 4236 active users before reminders failed (females 81.6%, 95% CI 80.5‐82.8), age 39.8 (95% CI 39.4‐40.2) years. During the failure period, the number of daily entries fell by 11.0% (95% CI 9.2‐12.8). More specifically, entries per 14-day period significantly declined from 10.2 (95% CI 10.1‐10.3) prefailure to 9.1 (95% CI 9.0‐9.2) during the failure period, followed by a rise to 10.2 (95% CI 10.1‐10.3) during the postfailure period (=79.2; <.001). The delay to make the daily entry increased by 46.3% (95% CI 45.8‐46.8), from 1.90 (95% CI 1.89‐1.90) days prefailure to 2.78 (95% CI 2.77‐2.79) days during failure, and returned to 1.85 (95% CI 1.84‐1.86) days postfailure (=155.4<.001). In addition, there was a significant rise in attrition rate by 32.2% (95% CI 8.1‐61.7) (from 4.0%, 95% CI 3.4‐4.6, in the prefailure period to 5.2%, 95% CI 4.6‐5.9, in the failure period, returning to 3.9%, 95% CI 3.4‐4.5, in the postfailure period, =3.10; =.002). Interaction analysis revealed that the effect of reminder failure was larger in males than in females (regarding entry delay), in persons with lower compared to higher headache frequencies (regarding number of daily entries and entry delay), and in persons with higher vs lower previous adherence rates (regarding number of daily entries, entry delay, and attrition). There was no interaction between age and reminder failure. Conclusions: This is the first study investigating the effect of daily reminders in a digital headache diary app. Results suggest that reminders are an effective means to improve adherence. Males, persons with low headache frequencies, and those with high adherence during the presence of reminders seem to benefit most. These results are important additions to our knowledge on compliance with digital health apps. Trial Registration: German Clinical Trials Register DRKS 00021081; https://drks.de/search/en/trial/DRKS00021081/details

2026-09-14T17:30:09-04:00 https://mhealth.jmir.org/2026/1/e95294 2026-09-14T17:00:20-04:00 Susann May Manuela Marquardt Gina Barzen Frances Seifert Mary Nyarko Antonia Niemeyer Sonja Gscheidle Liane Schenk Sebastian Spethmann Felix Muehlensiepen

<strong>Background:</strong> Nationwide electronic health records (EHRs) are intended to strengthen patient empowerment and improve information continuity across health care settings. In Germany, the electronic patient record (elektronische Patientenakte [ePA]) transitioned from an opt-in to an opt-out model in 2025. Initial survey data suggest that technical complexity and access requirements may hinder engagement; yet, little is known about how users experience this access process. <strong>Objective:</strong> This study explored users’ experiences of setting up and authenticating access to insurer-provided ePA apps and examined the barriers affecting successful access. <strong>Methods:</strong> We conducted a qualitative interview study with individuals covered by statutory health insurance. From 61 interviews conducted within the broader ePA4all project, 23 were selected because participants had attempted to access the ePA through an insurer-provided application and described at least 1 concrete action or event during setup or authentication. Semistructured telephone interviews were conducted between August and December 2025. Data were analyzed using Kuckartz’s structured qualitative content analysis. The process phases were developed inductively from the material. All 23 interviews were independently coded by 2 researchers, with differences resolved through consensus. A second analytic step examined how barriers interacted and accumulated across the access pathway. <strong>Results:</strong> The sample included 21 participants who had successfully accessed the ePA and 2 who had initiated but abandoned setup or authentication. Setup and authentication were experienced not as a single technical step but as an interdependent process comprising 5 phases: orientation, technical entry, verification, interruption, and transition to initial use. During orientation, incomplete or outdated information left requirements and procedural steps unclear. Technical entry required users to coordinate different apps, interfaces, and device requirements. Verification involved multiple credentials, identification services, and partly repeated security steps. Technical failures, administrative inconsistencies, postal procedures, and waiting periods interrupted progression and sometimes required users to repeat previously completed steps. After successful access, an unclear immediate benefit could limit the transition to initial use. Across phases, participants relied on digital competence, prior experience, persistence, and self-efficacy to navigate the process. Difficulties were also reported by participants with high affinity for technology. Barriers could accumulate across phases: insufficient orientation increased subsequent coordination work, failures produced interruptions and repeated attempts, and prolonged effort contributed to frustration or disengagement. <strong>Conclusions:</strong> Access to the opt-out ePA through insurer-provided apps is shaped by cumulative demands rather than by isolated technical problems. Formal provision of an EHR does not ensure that users can successfully complete the access process. Implementation should prioritize clear preregistration guidance, continuity across applications and identification services, resumable procedures, actionable error messages, and accessible support. More broadly, onboarding and authentication should be treated as integral stages in the implementation of patient-facing digital health infrastructures rather than as neutral technical prerequisites. <strong>Trial Registration:</strong> German Clinical Trials Register DRKS00037053; https://www.drks.de/search/de/trial/DRKS00037053

2026-09-14T17:00:20-04:00