Web-based intervention to reduce psychological barriers to insulin therapy among adults with non-insulin-treated type 2 diabetes: study protocol for a two-armed randomised controlled trial of 'Is insulin right for me?'.

INTRODUCTION

Psychological barriers to insulin therapy are associated with the delay of clinically indicated treatment intensification for people with type 2 diabetes (T2D), yet few evidence-based interventions exist to address these barriers. We describe the protocol for a randomised controlled trial (RCT) examining the efficacy of a novel, theoretically grounded, psychoeducational, web-based resource designed to reduce psychological barriers to insulin among adults with non-insulin treated T2D: 'Is insulin right for me?'.

METHODS AND ANALYSIS: Double-blind, parallel group RCT. A target sample of N=392 participants (n=196/arm) will be randomised (1:1) to 'Is insulin right for me?' (intervention) or widely available online resources (control). Eligible participants include adults (18-75 years), residing in Australia, currently taking oral hypoglycaemic agents to manage T2D. They will be primarily recruited via invitations and reminders from the national diabetes registry (from a purposefully selected sample of N≥12 000).

EXCLUSION CRITERIA: experience of self-administered injectable; previously enrolled in pilot RCT; 'very willing' to start insulin as baseline. Outcomes will be assessed via online survey at 2 weeks and 6 months. Primary outcome between-group: difference in mean negative Insulin Treatment Appraisal Scores (ITAS negative) at 2-week and 6-month follow-up.

SECONDARY OUTCOMES: between-group differences in mean positive insulin appraisals (ITAS positive) and percentage difference in intention to commence insulin at follow-up time points. All data analyses will be conducted according to the intention-to-treat principle.

ETHICS AND DISSEMINATION: Deakin University Human Research Ethics Committee (2020-073). Dissemination via peer-reviewed journals, conferences and a plain-language summary.

TRIAL REGISTRATION NUMBER: ACTRN12621000191897; Australian and New Zealand Clinical Trials Registry.