Prastyo, C.E. and Sari, D.M. 2026. Challenges of Sustainability of Employer-Based Retirement Healthcare Services in Indonesia: A Longitudinal Analysis of Demographic Transition and Healthcare Costs 2019–2023. Jurnal Ilmiah Kesehatan. 18, 1 (Mar. 2026), 238 – 249. DOI:https://doi.org/10.37012/jik.v18i1.3714.