# T1D REACHOUT–A Mobile App to Deliver Peer-Led Mental Health Support to Adults Living With Type 1 Diabetes: Co-Design and Development Process

**Authors:** Sadie Lee, Baray Sidhu, Parteek Johal, Ayman Azhar, Jonath Sujan, Matthias Görges, Tricia S Tang

PMC · DOI: 10.2196/71733 · 2026-03-20

## TL;DR

A mobile app called T1D REACHOUT was co-designed with adults living with type 1 diabetes to provide peer-led mental health support and improve diabetes distress.

## Contribution

The paper introduces a co-designed mobile app for peer-led mental health support in adults with type 1 diabetes, emphasizing user-driven development and implementation.

## Key findings

- The REACHOUT app features six key components identified through focus groups, including chatrooms and peer supporter profiles.
- During a 6-month pilot study, participants actively used the app, creating 179 small groups and sending over 10,000 messages.
- Successful implementation relied on co-design with users and hybrid development approaches.

## Abstract

For adults living with type 1 diabetes (T1D), diabetes-specific mental health support is limited. Peer support and digital health platforms are promising strategies for delivering this support to this population, particularly those from geographically marginalized communities. Mobile apps, in particular, can enhance self-management and deliver support. This paper describes the iterative co-design and development process of a novel mobile app for use in a pilot trial, T1D REACHOUT (REACHOUT), that aims to reduce the diabetes distress, a core facet of diabetes-specific mental health, of adults with T1D. An initial think tank and 6 focus groups were conducted with adults with T1D to better understand their support needs and identify platform requirements. Following this, we partnered with adults living with T1D, the “end users,” to iteratively co-design the REACHOUT app, enhancing usability and ensuring relevance. Adapting the open-source Rocket.Chat platform to user-defined requirements, we deployed the app in a single cohort pilot study. A network analysis of messages exchanged during the pilot study was performed to explore trends and patterns and demonstrate implementation feasibility. Pilot study outcomes informed further refinement before implementation in a randomized controlled trial. The implementation of the REACHOUT app features 6 key components identified in 6 initial focus groups: a 24/7 chatroom (a customized group messaging function with threads), topic-specific discussion boards, a peer supporter library, peer supporter profiles for a user-driven matching process, small group virtual sessions, and direct (one-to-one) messaging. Forty-six participants were encouraged to use any or all of the features as frequently as desired over a 6-month period during the pilot study. During this time, 179 private small groups were created, and 10,410 messages were sent, including 1389 chat room messages and 7116 direct messages; among these were 3446 messages exchanged between participants and their self-selected peer supporters. Key factors for successful implementation included (1) the co-design process involving comprehensive user engagement and (2) the opportunities realized through hybrid development. These findings offer generalizable lessons for mobile health research teams developing similar app-based interventions.

## Linked entities

- **Diseases:** type 1 diabetes (MONDO:0005147)

## Full-text entities

- **Diseases:** T1D (MESH:D003922), diabetes (MESH:D003920)
- **Species:** Homo sapiens (human, species) [taxon 9606]

## Figures

10 figures with captions in the complete paper: https://tomesphere.com/paper/PMC13004558/full.md

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Source: https://tomesphere.com/paper/PMC13004558