Modelling population dynamics, health system, and unmet need toward health burden: scenarios in ASEAN and WHO SEARO...

Universal health coverage is a cornerstone for achieving good health and well-being; however, its interaction with demographic and migration pressures remains underexplored, particularly in Southeast Asia. This study investigated how demographic pressure, migration pressure, health system capacity, and universal health coverage (UHC) influenced health burden across World Health Organization South-East Asia Region and Association of Southeast Asian Nations countries between 2000 and 2021 and simulated using a scenario-based model to forecast health burdens in 2030 and 2050.

Multiple data sets obtained from Global Repositories, Burden of Disease, Global Health Observatory, World Bank Open Data portal, and International Organization for Migration were extracted. Missing data were addressed using multiple imputations. Composite domains were validated using principal component analysis. Pathways were estimated using multilevel structural equation modelling, and temporal effects were assessed using linear mixed-effects models. Sensitivity analyses were performed to test alternative UHC rollout periods.

Migration pressure was positively associated with health system capacity (β = 0.757) and UHC (β = 0.553), both P < 0.001. Health system capacity increased UHC (β = 0.582), while demographic pressure reduced it (β = -0.800). Health burden was inversely associated with UHC (β = -0.679) and migration pressure (β = -0.446). Mediation analysis confirmed indirect effects of UHC. Linear mixed-effects models showed that disability-adjusted life years declined before UHC rollout, increased immediately after rollout, then decreased with higher UHC coverage. Scenario-based forecasts indicate moderate reductions by 2030 and greater declines by 2050, particularly in countries with strong and well-structured health systems.

UHC directly reduces health burden, whereas migration, health system capacity, and demographic pressure exert indirect effects. Forecasts indicate declining burden by 2030 and 2050, particularly in countries with strong health care systems. Continuous monitoring of sociodemographic pressures - along with sustained system capacity and UHC expansion - is essential for long-term health improvements in Southeast Asia.