Activity-Based Funding (T2A/DRG) between payment and regulation: Tariffs, sector, and implications for public health[La tarification à l’activité (T2A/GHM) entre paiement et régulation : tarifs, secteur et implications pour la santé publique]

Hospital funding is a key structuring lever of health systems, shaping care organization, professional behavior, and equity of access. In France, Activity-Based Funding (T2A), introduced between 2004 and 2008, relies on lump-sum payments per hospital stay based on homogeneous patient groups. While originally designed to promote transparency, efficiency, and equity between public and private sectors, T2A has revealed significant limitations: growing complexity, strategic coding practices, and tensions between performance-based incentives and public service missions. Over time, T2A has evolved into a multi-purpose instrument—used not only for funding, but also to regulate care provision and generate epidemiological data. Yet these objectives may conflict: financial incentives for coding may distort data quality, encouraging upcoding at the expense of reliable public health analysis. Twenty years after its implementation, a marked gap has emerged between the complex classification system developed by regulators and the simplified version used in practice. Fewer than 500 DRGs (about 20%) account for 80% of hospital activity, pointing to unnecessary complexity in the current system. Meanwhile, the tariff ratio between private and public hospitals has stabilized around 48%, reflecting persistent structural differences. While this may stem from disparities in medical personnel costs, it may also signal deeper organizational or functional divides. This article offers a critical perspective on T2A—tracing its origins, evolution, and uses—while questioning its ability to address today's challenges of sustainability, equity, and care relevance.