Observation Status Related to U.S. Hospital Records - HCUP

separate data set on observation status patients from hospital emergency andoutpatient departments in Massachusetts. There are no national studies on the issue.In the HCUP inpatient and outpatient databases, we found that the percent of recordswith observation services varied considerably across States. In five States inpatientdatabases with observation status codes, the percent of the States' inpatient dischargeswith observation services ranged from 0.5 to 6.2 percent per year. In four HCUP Stateoutpatient databases, the percent of the States’ outpatient records with observationservices ranged from 0.4 to 8.0 percent per year. There was little variation in the codingof observation services across discharge quarter in both the inpatient and outpatientdatabases, but there was great variation among hospitals. Hospitals coded observationservices on 0% to 40% of their inpatient records, 0% to 70% of their ambulatory surgeryrecords, and 0% to 30% on their emergency department records. In a number ofStates, many hospitals coded no observation services on their inpatient and/oroutpatient records.We further explored the HCUP data for internal consistency on observation status andfor whether hospitals typically count pre-admission observation days as part of theinpatient length of stay. For inpatient discharges without any observation servicescoded, we expected to find the length of stay equal to room and board days. We foundthat 1 to 10 percent of those discharges, depending on the State, did not havecongruence between length of stay and room and board days. For inpatient dischargeswithout any observation services, when the length of stay was not equal to room andboard days, length of stay was usually just as likely to be "greater than" as opposed to"less than" R&B days. For inpatient discharges with observation services, length of staywas more likely to be greater than the room and board days, suggesting thatobservation services are at least sometimes included in the inpatient length of staycalculation by the hospital. However, when days in observation status were added toroom and board days, the length of stay was still more likely to be greater than the sum.This suggests that either other services are being counted in length of stay or the daysfor room and board and/or observation services are not accurately captured on thedischarge record in the revenue codes and units.We also examined the length of stay on outpatient records. We found that not allemergency department and ambulatory surgery visits of more than 24 hours haveobservation time associated with them. This suggests that not all of the time inobservation status is coded on the outpatient record in the revenue codes or there isanother categorical definition that applies to these cases.Because of these internal inconsistencies, we do not recommend further analysis ofobservation services with HCUP inpatient and outpatient databases. It is not possible todetermine whether the variation in percent of inpatient and outpatient discharges withobservation services is because of practice differences in the use of observationservices or because observation services are not recorded consistently in the revenuecodes. Further, we caution analysts that inconsistent use and coding of observationservices may affect findings in studies of inpatient utilization for some conditions.ii