Effectiveness and adherence in a tirzepatide-supported digital weight-loss programme in Australia: A real-world observational study.

AIMS: Obesity is a growing global health crisis; pharmacotherapies such as tirzepatide combined with multidisciplinary lifestyle support have shown promise but real-world evidence in digital weight-loss services (DWLSs) is limited. This retrospective study evaluated 6- and 12-month weight loss, adherence and predictors of outcomes in an Australian cohort using a tirzepatide-supported medicated DWLS. MATERIALS AND METHODS: All patients initiating tirzepatide through the Juniper AU DWLS between 1 September 2024 and 23 April 2025 (n = 4309) were analysed. The study population was predominantly female (92.9%) and Caucasian (81.9%), with a mean age of 41.46 years and a mean baseline body mass index of 32.9 kg/m. Primary endpoints were programme adherence at 6 and 12 months and mean percentage weight loss among adherent patients. Adherence required ≥5 medication orders and a weight entry at 173-193 days after programme initiation (6 months), or ≥10 orders and a weight entry 355-375 days post-initiation (12 months). Full cohorts were analysed using last observation carried forward imputation. RESULTS: At 6 months, 31.7% met adherence criteria; mean weight loss among adherent patients was 16.9% (±8.6; 95% CI 16.6-17.2), with 98.0% achieving ≥5% weight reductions. At 12 months, 16.1% were adherent; mean weight loss was 22.7% (±7.2; 95% CI: 19.8-22.6) and 100% of patients reached the ≥5% milestone. Multivariable models identified 1-month weight loss as the strongest predictor of 6- and 12-month outcomes; sustained weekly weight tracking and health coach messaging were strongly associated with both retention and greater weight loss. Paradoxically, very frequent weight tracking in month one correlated with poorer outcomes and reduced retention. Side effects were common but mostly mild/moderate and did not correlate with weight loss or programme retention. CONCLUSIONS: Tirzepatide plus multidisciplinary digital care yields large clinically meaningful weight loss among engaged users, but low adherence limits population-level effectiveness. Early clinical response and sustained engagement are key drivers of adherence; however, interventions are needed to manage early weight-loss expectations.