Background: Background: Latina adolescents report low levels of moderate-vigorous physical activity (MVPA) and high lifetime risk of lifestyle-related diseases. There is a lack of MVPA interventions targeted at this demographic despite documented health disparities. Given their high rates of using mobile technology, interventions delivered through mobile devices may be effective for this population. Objective: Objective: The current paper examines efficacy of the Chicas Fuertes intervention in increasing MVPA across six months in Latina adolescents. Methods: Methods: Participants were Latina adolescents (ages 13-18) in San Diego County who reported being underactive (<150 minutes/week of MVPA). All participants received a wearable fitness tracker (Fitbit Inspire HR); half were randomly assigned to also receive the multimedia intervention. Intervention components included a personally tailored website, personalized texting based on Fitbit data, and social media. The primary outcome was change in minutes of weekly MVPA from baseline to six months (6m), measured by ActiGraph accelerometers and the 7-Day Physical Activity Recall Interview. Changes in daily steps using Fitbit devices were also examined to test intervention efficacy. Results: Results: Participants (N=160) were 15.3 years old on average, and mostly second generation in the U.S. For ActiGraph-measured MVPA, participants in the Intervention group (N=83) increased from a median of 0 min/week at baseline (IQR 26) to 64 min/week at 6m (IQR 28) compared to Control participants, who showed increases from a median of 0 at baseline (IQR 24) to 41 min/week at 6m (IQR 21) (P=.04). Self-reported MVPA increased in the Intervention group from a median of 119 min/week at baseline (IQR 122.5) to 147 min/week at 6m (IQR 85) compared to Control participants, who showed increases from a median of 120 (IQR 186.25) at baseline to 124 min/week at 6m (IQR 69) (P=.03). Steps also increased in both groups, with the Intervention group showing significantly greater increases (P=.03). Conclusions: Conclusions: This intervention was successful in using a tailored technology-based strategy to increase MVPA in Latina adolescents and provides a promising approach for addressing a key health behavior. Given the scalable technology used, future studies should focus on broad scale dissemination to address health disparities. Clinical Trial: ClinicalTrials.gov NCT04190225; https://clinicaltrials.gov/study/NCT04190225?id=NCT04190225

Background: Pediatric to adult health service (AHS) transition is an inevitable but challenging time for many adolescents and young adults (AYAs) with a chronic illness. As the responsibility of illness management begins to shift from parents to the AYA themselves, many AYAs fail to transition in a timely manner which has important health consequences. Mobile apps have the potential to assist AYAs in self-managing their condition during this vulnerable time, but empirical data on app uptake as well as efficacy with respect to transition outcomes and illness control are lacking. Objective: This pragmatic, single arm pilot trial aimed to evaluate AYA usage of a mobile app called ‘TransitionMate’ (TMApp) which was purpose-built to support chronic illness self-management for youth undergoing transition. Secondary aims were to assess AHS attendance and changes in illness control over the first 12 months post-transition. Upon demonstration of TMApp feasibility (≥70% of participants using TMApp at least once a month), a randomized controlled trial was planned to test efficacy of the app in relation to transition and illness control outcomes. Methods: AYAs aged 16-19 years who were transitioning out of two major pediatric hospitals in Sydney, Australia were recruited. Just prior to transition, participants’ demographic and clinical details were collected and TMApp was installed on their mobile devices. Participants were contacted by telephone at six and 12 months for information on self-reported usage, app usefulness and other feedback. Quantitative cohort-level usage data, including the number of times specific app features were accessed, was tracked via mobile analytics. At 12 months, electronic medical records (eMR) from participants’ designated AHS were accessed for data on AHS attendances, measures of illness control and unplanned hospitalizations. Results: 73 AYAs (30 male; median age 18 years) were recruited, with one withdrawing participation in the first month. Participants were primarily from three chronic illness subgroups: diabetes mellitus (n=23); inflammatory bowel disease (n=19); and cystic fibrosis (n=9). 50% of participants reported using TMApp at one month post-transition. Self-reported usage rates subsequently fell to 25% and 11% at six and 12 months, respectively. Mobile analytics data broadly corroborated self-reported usage. Eight participants who continued to use TMApp until 12 months gave a median usefulness rating of 8/10. Over two-thirds (68%) of participants successfully transitioned to their designated AHS by 12 months. Among the successful transitioners who had illness control data available on eMR, over 80% maintained a stable/improved illness status at six and 12 months. Conclusions: Results showed that TMApp was not used regularly enough by AYAs to demonstrate feasibility and justify progression to a randomized controlled trial. Despite low app uptake, over two-thirds of participants successfully transitioned suggesting that TMApp had minimal influence on transition outcomes. Clinical Trial: Australian New Zealand Clinical Trials Registry ACTRN12620000074998; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=377349&isReview=true.