Adverse events related to hospital care: a retrospective medical records review in a Swiss hospital.

Retrospective records reviews carried out in several countries have shown substantial rates of adverse events (AE) among hospitalized patients, preventable in half the cases. As no such data have been recorded in Switzerland, we estimated the incidence of AE in one acute care hospital as a basis for a safety improvement program. A two steps retrospective records review (screening criteria and full review of positively screened records). A medium size community hospital. A stratified sample of 400 surgical and 600 medical hospitalizations whose records fulfilled a set of information quality criteria. Not applicable. Adverse events, preventable adverse events and extent of resulting harm. The proportion of hospitalizations with at least one AE was 12.3% (95% CI: 10.4-14.1) whereas the overall hospital incidence rate was 14.1% (95% CI: 12.0-16.2). Nearly half of AE were judged preventable, corresponding to one or more preventable AE in 6.4% of hospitalizations (95% CI: 5.0-7.8). Sixty percent of AE resulted in no or minor impairment at discharge whereas 23% resulted in severe disability. AE were twice more frequent in surgical patients, and preventable AE resulted more often in severe impairment than unpreventable AE. No death was attributed to an AE. The proportion of stays with an AE increased with age and length of stay. The incidence of preventable AE in patients hospitalized in one Swiss hospital is comparable to previously reported rates. Further, patient safety improvement is needed, especially among older patients, and for surgical procedures