Efficacy and Feasibility of Just‐in‐Time Nudging in Reducing Evening Snacking Measured by Continuous Glucose Monitoring in Adults With Type 2 Diabetes: A Micro‐Randomized Study

ABSTRACT Aims This study aimed to determine whether in people with Type 2 diabetes mellitus (T2DM), a digital nudge delivered by a smartphone app soon after dinner reduces subsequent snacking events as measured by continuous glucose monitoring (CGM). Methods Participants: Adults with T2DM, managed with diet or stable oral antidiabetic medication for at least 3 months, and who habitually snacked after dinner on ≥ 3 nights/week. Design: Pictographic nudges were co‐designed with consumers. After‐dinner snacking behaviours were confirmed during a 2‐week Lead‐In phase by CGM. Thereafter, eligible participants were micro‐randomized daily (1:1, MRT phase) to either a pictographic nudge delivered‐in‐time (Intui Research) or no nudge for a second 2‐week period. The primary outcome was the difference in incremental area under the CGM curve (net‐iAUC) between nudging days and non‐nudging days during the period 90‐min post‐dinner until 4 AM. Results Sixty‐six participants completed the Lead‐In phase and 56 completed the MRT phase with available CGM data. CGM data were collected over 911 nights during the Lead‐In phase and 780 nights during the MRT phase, with a total of 410 digital nudges sent. Over the entire 2‐week period there was no effect of nudging on the primary outcome (net‐iAUC). However, secondary analyses showed that there was an initial nudge effect that faded over time. Similar results were observed for snacking behaviour and CGM time‐in‐range. Conclusion This study provides preliminary feasibility of delivering just‐in‐time nudges in adults with T2DM, with no overall glycaemic benefit. Exploratory early effects warrant confirmation and investigation of strategies to sustain efficacy. Trial Registration ACTRN12622000531718