Evaluating the effectiveness of the D1 Now intervention to improve outcomes among young adults with type 1 diabetes: Protocol for a cluster randomised controlled trial

BackgroundYoung adults living with type 1 diabetes (T1D) often experience sub-optimal outcomes due to competing life demands, disruptions in care, reduced clinic attendance, and difficulties in self-management. To improve outcomes among this population, we developed and piloted the D1 Now intervention using a user-centred and theory-informed approach. This protocol describes a cluster randomised controlled trial (RCT) to test the effectiveness and cost-effectiveness of the D1 Now intervention. MethodsA cluster RCT seeking to recruit 348 young adults (aged 18-25) with T1D from 12 hospital diabetes centres in Ireland. Centres will be randomised to receive either standard care or the D1 Now intervention, which includes two components: an agenda-setting tool and a support worker. The primary outcome is the change in HbA1c from baseline to 12-month follow-up. Secondary outcomes include patient-reported psychosocial outcomes, clinical outcomes, self-management outcomes and healthcare utilisation. We will collect data through blood samples, online patient surveys, and patient records at baseline and 12 months. Additionally, we will conduct a cost-effectiveness evaluation and a mixed-methods process evaluation. DiscussionWe anticipate that the D1 Now intervention will be both effective and cost-effective in improving clinical and psychosocial outcomes for young adults compared to standard care. The findings from the process evaluation will shed light on how the intervention works (or not) and how implementation into health services (if warranted) can be optimised. If effective, D1 Now will offer a sustainable model of care to support engagement and self-management for young adults living with T1D. Trial registrationISRCTN Identifier: ISRCTN28944606. Date applied 01 May 2025