AI-assisted medical coding in hospitals has contributed approximately $942 million in additional costs to Blue Cross Blue Shield health plans between 2023 and 2025, with much of the increase stemming from secondary diagnoses that moved patients into higher-paying reimbursement categories. While some diagnoses identified by AI are legitimate, roughly 70% of the identified billing increase involved additional diagnoses without corresponding changes in patient care, raising concerns that AI is accelerating existing billing incentives rather than reducing costs.