Association Between Medicare Policy Reforms and Changes in Hospitalized Medicare Beneficiaries' Severity of Illness

Key Points Question Did the expansion of secondary diagnosis codes in January 2011 allow more diagnosis codes to be reported per hospitalization, and were incentive payments for health information technology associated with changes in measured severity of illness? Findings In this cohort study of 47 951 443 discharges at 2850 hospitals, expansion of secondary diagnosis coding positions was associated with a statistically significant increase in measured severity of illness among hospitalizations for all diagnoses, diagnoses commonly targeted by incentive programs, and untargeted diagnoses. Health information technology incentives were associated with a statistically significant increase in condition categories for all diagnoses and targeted diagnoses. Meaning Changes in Medicare policies appear to be associated with increases in measured severity of illness; related policy changes may incentivize more thorough documentation of disease burden without underlying changes in patient severity.