LAUSR

Attention to 10th Revision of the International Classification of Disease (ICD-10)-CM Z-codes as a mechanism for capturing social risk has grown over the years. However, it remains unclear whether the use of Z-codes has changed over time. This study sought to examine the trends in Z-code use between their introduction in 2015 and the end of 2019 across 2 markedly different states. Using the Healthcare Cost and Utilization Project, all emergency department visits or hospitalizations at short-term general hospitals in Florida and Maryland from 2015 Q4 through 2019 were identified. This study focused on a subset of the Z-codes that are intended to capture social risk to identify the percentage of encounters with a Z-code, percentage of facilities using Z-codes, and facility median of number of encounters with a Z-code per 1000 encounters across quarters, states, and care settings. In total, 495,212 (0.84%) of 58,993,625 encounters had a Z-code. Despite Florida's higher area deprivation, Z-codes were less frequently used and increasing more slowly than when compared with those in Maryland. There were 2.1 times the use of Z-codes in Maryland than in Florida at the encounter level. This difference was also seen when evaluating the median number of encounters with a Z-code, per 1000 encounters (12.1 vs. 3.4). Z-codes were more commonly used at major teaching facilities, and for patients who were uninsured or on Medicaid. The use of ICD-10-CM Z-codes has increased over time, with this increase occurring at nearly all short-term general hospitals. Their use was higher in Maryland than in Florida and among major teaching facilities.