Digital engagement enhances dual GIP/GLP-1 receptor agonist and GLP-1 receptor agonist efficacy: A retrospective cohort analysis of a digital weight loss service on outcomes and safety.

AIMS: We evaluated the weight loss efficacy and safety of a national digital weight loss service (DWLS) and explored associations between digital engagement and outcomes in adults prescribed dual GIP/GLP-1RA and GLP-1RA. MATERIALS AND METHODS: We conducted a retrospective longitudinal cohort analysis of adults prescribed dual GIP/GLP-1RA and GLP-1RA between August 2024 and July 2025 within the Voy DWLS in the United Kingdom (UK). Digitally engaged patients met all three criteria: (i) ≥1 coaching session; (ii) weekly weight logging (≥4/month); and (iii) ≥1 additional in-app interaction. Weight-loss trajectories were modelled using mixed models for repeated measures (MMRM). Kaplan-Meier methods and Cox models examined time to attain weight loss thresholds (≥5, ≥10, ≥15, ≥20, ≥25%). Safety events were summarised as rates per 1000 patient-months with 95% CIs. RESULTS: The cohort included 106 653 adults (mean age 42.3 ± 12.7 years; 77.9% female; baseline BMI 35.2 ± 6.2 kg/m2). Whilst 79.7% (n = 84 955) used the digital application, 5.7% (n = 6086) met maximal engagement, with 100 567 classed as not engaged. Across 11 months, engaged patients achieved greater adjusted weight loss than not engaged (21.5% [95% CI -22.0 to -21.1] vs. 17.0% [-17.2 to -16.8]; absolute difference 4.5 percentage points; p < 0.001). Kaplan-Meier analyses showed consistently higher likelihood of milestone attainment for engaged participants (≥5%: HR 1.42, 95% CI 1.38-1.46; ≥10%: HR 1.46, 1.41-1.52; ≥15%: HR 1.53, 1.45-1.61; ≥20%: HR 1.62, 1.50-1.75; ≥25%: HR 1.86, 1.64-2.10; all p < 0.001). Safety analyses over 290 050 patient-months showed incidence 1.57 per 1000 patient-months, with no excess risk in engaged groups (IRR 0.83, 95% CI 0.60-1.15). CONCLUSIONS: Digital engagement was associated with 4.5 percentage points greater weight loss (21.5% vs. 17.0%), faster milestone achievement, and comparable safety profiles.