Adverse events in British hospitals: preliminary retrospective record review.

OBJECTIVES To examine the feasibility of detecting adverse events through record review in British hospitals and to make preliminary estimates of the incidence and costs of adverse events. DESIGN Retrospective review of 1014 medical and nursing records. SETTING Two acute hospitals in Greater London area. MAIN OUTCOME MEASURE Number of adverse events. RESULTS 110 (10.8%) patients experienced an adverse event, with an overall rate of adverse events of 11.7% when multiple adverse events were included. About half of these events were judged preventable with ordinary standards of care. A third of adverse events led to moderate or greater disability or death. CONCLUSIONS These results suggest that adverse events are a serious source of harm to patients and a large drain on NHS resources. Some are major events; others are frequent, minor events that go unnoticed in routine clinical care but together have massive economic consequences.