Length of Enrollment of Beneficiaries in the Brazilian Supplementary Health System: An Observational Analysis Using Data from the National Supplementary Health Agency (ANS)

Abstract

Objective: To describe and analyze beneficiaries’ length of enrollment in the Brazilian supplementary health system, according to type of contracting arrangement, type of health plan operator, and geographic region. Methods: This was a retrospective observational study based on publicly available data from the Open Data Plan of the Brazilian National Supplementary Health Agency (ANS), using information from the Beneficiary Information System (SIB/ANS) from 2000 to 2024. The study population was estimated considering only active beneficiaries, whereas the mean length of enrollment was calculated using both active and inactive beneficiaries, with weighted averages based on the number of enrollment links. Analyses were stratified by contracting modality, operator type, and major geographic regions of the country. Results: Data from approximately 51.6 million active beneficiaries were analyzed. The overall mean length of enrollment was approximately 4.7 years. Individual or family plans showed the longest mean duration (8.4 years), whereas employer-sponsored group plans accounted for the largest share of beneficiaries but exhibited shorter enrollment periods (3.9 years). Self-managed and philanthropic operators presented the highest mean durations (9.5 and 6.3 years, respectively). Regional heterogeneity was observed, with the longest mean enrollment in the South region (5.2 years) and the shortest in the Central-West region (3.9 years). Conclusion: Length of enrollment in the Brazilian supplementary health system is strongly influenced by the type of contracting arrangement, the institutional model of operators, and the regional context, reflecting the interaction between labor market dynamics, regulatory frameworks, and the structure of the health sector.