Type 1 diabetes (T1D) demands self-management skills, knowledge and confidence to prevent medical complications. Adolescents living with T1D have distinct developmental challenges resulting in a worsening in glycaemic stability, irregular care and an increased risk for complications all while transitioning to adult healthcare. Age-specific online platforms could facilitate transition by fostering self-management education and support. The Support online self-guided training platform has been shown to increase the confidence of adults with T1D in managing their glycaemia. We aim to test the effectiveness of Support-t (ie, adapted for youth), compared with usual care, in improving haemoglobin A1c (HbA1c) and to understand the context of its implementation.

We will conduct a multisite, assessor-blinded, randomised controlled, parallel group, two-arm, superiority trial, evaluating effectiveness and implementation of Support-t versus usual care in 200 adolescents (14–16 years old) living with T1D. The active arm will have an 18-month access to Support-t, and their healthcare team will be trained on the platform’s content. The control arm will receive usual care. The primary outcome is HbA1c at 18 months. Secondary outcomes include self-efficacy for diabetes self-management, transition readiness, diabetes-specific quality of life, diabetes distress, continuous glucose monitoring metrics, number of severe hypoglycaemic events, diabetic ketoacidosis, T1D-related emergency department visits and hospitalisations as well as engagement and satisfaction. A subgroup of participants in the active arm and of healthcare providers will be interviewed assessing barriers, facilitators, engagement and fidelity of the intervention. Primary analysis will be by intention-to-treat. The difference in mean HbA1c at 18 months (with a 95% CI) will be calculated between both arms. A cost-effectiveness analysis is also planned.

December 8, 2024 version of the protocol was approved by the McGill University Health Centre Research Ethics Board (MP-37-2024-9734). Results will be disseminated through peer-reviewed publications and patient-partners’ network.

ClinicalTrials.gov (NCT05910840).