Abstract
Forecasting the Defined Daily Dose per 1,000 Population (DID) of Metformin among the Insured under the Iranian Health Insurance Organization: An Analysis of National Values, Trends, and Policy Implications for 2025–2030

Background: Metformin, a key treatment for type 2 diabetes, is widely used among Iran Health Insurance Organization (IHIO) beneficiaries, reflecting rising diabetes prevalence due to aging, urbanization, and lifestyle shifts. Accurate prediction of Defined Daily Dose per 1,000 Inhabitants (DID) is vital for healthcare planning and drug supply stability. This study forecasts metformin DID for IHIO (2025–2030) using optimal modeling.

Methods: Data from IHIO’s medical and insurance claims (2011–2024) were analyzed. DID projections were derived using multiple models, with the logarithmic model selected for its superior fit (highest R²). Linear regression identified trends, while descriptive statistics examined historical patterns. Validation included R² analysis, cross-validation, and model comparisons.

Findings: DID is projected to increase from 6.05 (2025) to 6.77 (2030), with 2.3% annual growth. Historical data showed a peak (5.98 in 2019) and a decline (4.85 in 2021, likely due to COVID-19). The logarithmic model (R² = 0.92) best predicted the upward trend.

Conclusion: The logarithmic model’s strong fit (R² = 0.92) supports the projected DID rise, driven by growing diabetes prevalence. Challenges such as economic barriers (e.g., sanctions) or supply constraints may hinder access. Proactive policies are needed to ensure metformin availability. Future research should explore regional disparities, alternative models, and economic influences.