Accepted for/Published in: JMIR Formative Research
Date Submitted: Nov 28, 2025
Date Accepted: Jul 19, 2026
Warning: This is an author submission that is not peer-reviewed or edited. Preprints - unless they show as "accepted" - should not be relied on to guide clinical practice or health-related behavior and should not be reported in news media as established information.
Losing Weight, Gaining Value: Long-term Cost and Health Impact of a Digital Obesity Intervention in Germany
ABSTRACT
Background:
Obesity imposes a substantial economic burden, accounting for an estimated 10% of total healthcare expenditures in Germany. Digital health applications have demonstrated effectiveness in supporting weight management among individuals with obesity; however, evidence regarding their long-term economic impact remains limited.
Objective:
The objective of this study was to evaluate the long-term cost-effectiveness of the Oviva Direkt app for obesity treatment in the German healthcare context.
Methods:
A cohort-based Markov model was developed, informed from the Core Obesity Model, to evaluate the cost-effectiveness of a digital health application for weight management versus care as usual over a 10-year time horizon from a societal perspective. The model simulates disease progression using 6-month and annual cycles after an initial monthly phase and includes health states for key obesity-related comorbidities such as type-2-diabetes (T2D), acute coronary syndrome (ACS), stroke, cancer, and obstructive sleep apnoea. Patients enter the model at age 46 with a BMI of 30–45 kg/m², based on trial data. The analysis considered direct and indirect costs, life-years, and quality-adjusted life-years (QALYs). The primary outcome was the incremental cost-effectiveness ratio (ICER), complemented by net monetary benefit (NMB) analysis. Weight trajectories were extrapolated based on trial results using three scenarios (base case decay model, weight maintenance, full regain). Sensitivity analyses were conducted to assess uncertainty.
Results:
Under base case assumptions, the digital health application dominated care as usual, yielding cost savings of 3,511.85 € and a QALY gain of 0.0683 (≈3.6 weeks in perfect health). Direct medical costs were reduced by nearly 520 €. T2D prevalence was 1.6 percentage points lower, reducing time lived with diabetes by 8 months. Scenario analyses confirmed consistent cost-effectiveness.
Conclusions:
Digital health applications for weight management are cost-effective and clinically beneficial for individuals with obesity in Germany. These results add to growing evidence for digital health solutions, aligning with findings from applications for other conditions such as depression and multiple sclerosis.
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