Using inpatient hospital discharge data to monitor patient safety events.

The development of systematic and sustainable surveillance systems is necessary for the creation of patient safety prevention programs and the evaluation of improvement resulting from innovations. To that end, inpatient hospital discharges collected by the Pennsylvania Health Care Cost Containment Council were used to investigate patient safety events (PSEs) in Pennsylvania in 2006. PSEs were identified using external cause of injury codes (E-codes) in combination with the Agency for Healthcare Research and Quality's patient safety indicators (PSIs). Encounters with and without PSEs were compared with regard to patient age, sex, race, length of stay, and cost. Approximately 9% of all Pennsylvania inpatient discharges had a PSE in 2006. Patients with a PSE were on average older, male, and white. The average length of stay for a PSE was 3 days longer and $35 000 more expensive than a non-PSE encounter. It was concluded that E-codes and PSIs were useful tools for the surveillance of PSEs in Pennsylvania, and that administrative data from healthcare organizations provide a consistent source of standardized data related to patient encounters, creating an opportunity to describe PSEs at the population level.