The intent of excluding ED/observation visits that result in an inpatient stay is to not double count events when the diagnosis category is the same for both events. For example, an ED visit for alcohol disorder that resulted in an inpatient stay for alcohol disorder is reported only once in the “Inpatient Stay” category. However, an ED visit for alcohol disorder that resulted in an inpatient stay for opioid disorder is reported in both the ED category (alcohol diagnosis category) and the Inpatient Stay category (opioid diagnosis category). An ED visit for alcohol disorder that resulted in an inpatient stay for something other than an alcohol, opioid or other or unspecified drug disorder (e.g., heart attack) is reported only once in the “ED” category.
HEDIS 2019