This is a multi-centre, prospective, randomized, open-label controlled trial designed to evaluate the effectiveness of a flexible digital insulin dose calculator in children under 12 years of age with Type 1 Diabetes Mellitus (T1DM) managed with multiple daily injections (MDI). Participants will be stratified by continuous glucose monitoring (CGM) use and baseline HbA1c, and randomised to receive either standard care alone or standard care plus the insulin dose calculator tool for 6 months.

The primary outcome is the change in HbA1c from baseline to 6 months. Secondary outcomes include CGM-derived glycaemic metrics (Time in Range, Time Below Range, Time Above Range, and Coefficient of Variation), total daily insulin dose (units/kg/day), healthcare provider contact frequency, and caregiver-reported usability and satisfaction. The study aims to determine whether the use of a structured digital decision-support tool improves glycaemic control and supports safer insulin dosing in paediatric patients with T1DM.

Type 1 Diabetes Mellitus (T1DM) in children requires intensive insulin therapy and frequent dose adjustments based on carbohydrate intake, glucose levels, and individualised insulin parameters. Although carbohydrate counting is widely practised in paediatric diabetes management, translating these principles into accurate insulin dosing remains complex. Caregivers must integrate insulin-to-carbohydrate ratios, correction factors, pre-meal glucose values, and -when applicable- continuous glucose monitoring (CGM) trend information. This process is prone to calculation errors and variability, which may contribute to suboptimal glycaemic outcomes.

While advanced technologies such as insulin pumps and hybrid closed-loop systems can automate insulin delivery, many children worldwide continue to use multiple daily injections (MDI). For this population, structured digital decision-support tools may help standardise insulin dose calculations and reduce caregiver burden. However, high-quality prospective evidence evaluating such tools in paediatric MDI users remains limited.

This study is a multi-centre, prospective, randomised, open-label controlled trial evaluating the clinical impact of a flexible digital insulin dose calculator in children under 12 years of age with established T1DM managed with MDI and carbohydrate counting. Participants will be stratified according to CGM use and baseline glycaemic control, then randomised to either standard care alone or standard care plus access to the insulin dose calculator for a 6-month period.

The intervention consists of structured training in the use of the digital calculator, which integrates individualised insulin-to-carbohydrate ratios, correction factors, and glucose inputs to generate dosing recommendations. The study will assess whether integration of this tool into routine care improves overall glycaemic control and glycaemic stability compared with standard practice alone. In addition, the study will explore effects on insulin titration patterns, healthcare utilisation, and caregiver experience.

The trial is designed to reflect real-world paediatric diabetes practice across multiple international sites. Data will be collected during routine clinical encounters over a 6-month follow-up period. The findings are expected to provide evidence regarding the effectiveness, feasibility, and scalability of a non-invasive digital decision-support intervention aimed at improving insulin dosing accuracy and supporting families managing paediatric T1DM.

Inclusion Criteria:

• Children and adolescents < 12 years
• Diagnosed with Type 1 Diabetes Mellitus (T1DM)
• Duration of diagnosis > 1 year
• Using a multiple daily injection (MDI) regimen
• Practising carbohydrate counting for at least 1 month before enrolment

Exclusion Criteria:

• Use of an existing insulin dose calculator (e.g., mobile application or bolus advisor) within the last 3 months
• Diagnosis of other types of diabetes (e.g., Type 2 diabetes mellitus, monogenic diabetes)
• Use of insulin regimens other than multiple daily injections (MDI) (e.g., insulin pump therapy)

De-identified individual participant data underlying the published results may be made available upon reasonable request to the principal investigator, subject to institutional approval, data protection regulations, and a data-sharing agreement. Data sharing will not include direct identifiers and will comply with applicable ethical and legal requirements.

6 months after publication of the primary study results. Up to 2 years after publication of the primary results.

De-identified individual participant data underlying the published results (including primary and secondary outcome data, data dictionary, and statistical analysis plan) may be made available to qualified researchers for scientifically sound research purposes. Access will be granted upon reasonable request to the Principal Investigator and subject to institutional review, ethics approval where applicable, and execution of a formal data-sharing agreement. Data will be provided in a de-identified format and shared through secure electronic transfer or a controlled-access repository in accordance with applicable data protection regulations.