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Report (OEI-06-09-00092)

Few Adverse Events in Hospitals Were Reported to State Adverse Event Reporting Systems

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Previous OIG work found that an estimated 27 percent of Medicare beneficiaries hospitalized in October 2008 experienced harm from medical care, either serious adverse events (defined as events resulting in prolonged hospitalization, permanent disability, life-sustaining intervention, or death) or temporary harm events (defined as events requiring intervention but not resulting in lasting harm). To determine this rate of adverse and temporary harm events (referred to collectively as events), we examined medical records for a nationally representative sample of 780 hospitalized Medicare beneficiaries in October 2008. Prior OIG work also found that in 2008, about half of States operated adverse event reporting systems to monitor the occurrence of events in hospitals. Typically, these States required hospitals to report only specific types of events and analyzed the events in aggregate. This memorandum extends our prior work by providing national estimates for the extent to which events experienced by Medicare beneficiaries occurred in States that operated adverse event reporting systems, whether States required reporting of the identified events, and whether the hospitals reported the events to the State systems.


We reviewed State policies to determine which events identified in our previous study were ones that States required hospitals to report. We then collected any reports about these events that hospitals sent to States. Based on the national random sample of hospitalized Medicare beneficiaries, we projected rates for the following: events experienced by Medicare beneficiaries that occurred in States that operated adverse event reporting systems in 2008 and events that these States required hospitals to report to the State systems. We also determined which events hospitals reported to these State systems.


We found that an estimated 60 percent of adverse and temporary harm events nationally occurred at hospitals in States with reporting systems, yet only an estimated 12 percent of events nationally met State requirements for reporting. We also found that hospitals reported only 1 percent of events. Most of the events that States required to be reported but that hospitals did not report were not identified by internal hospital incident reporting systems. This suggests that low reporting to State systems is more likely the result of hospital failure to identify events than of hospitals' neglecting to report known events.


This memorandum report does not contain recommendations. However, we emphasize that CMS, States, and other stakeholders should be aware of this low rate of reporting to State systems as they consider strategies to reduce adverse events in hospitals.

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