Abstract DP279: Hospital Variation in Documentation of NIHSS in Medicare Claims

Background: The NIHSS is critical for adequate risk adjustment in claims-based analyses of patients with acute ischemic stroke (AIS). In 2016, an ICD-10-CM code was introduced and in 2023, the Centers for Medicare and Medicaid Services (CMS) began usings NIHSS in risk adjustment for hospitals’ 30-day mortality performance measure for stroke. This application may incentivize documentation of higher scores more than lower scores. We sought to examine hospital-level variation in documentation rates, changes in hospitals’ documentation patterns over time, and the extent to which hospitals used the full range of possible scores. Methods: We used traditional Medicare claims data from 2016-2019 to identify AIS encounters. We included all hospitals with at least 5 AIS encounters (emergency department or inpatient) in each year of the study period. For each hospital we determined the proportion of encounters with NIHSS documented, by year, and used a linear regression model to examine the hospital-level trend in the proportion of cases with NIHSS documented over time. We examined the proportion of NIHSS