Patient safety indicators for England from hospital administrative data: case-control analysis and comparison with US data

Objective To assess the feasibility of deriving patient safety indicators for England from routine hospital data and whether they can indicate adverse outcomes for patients.Design Nine patient safety indicators developed by the United States Agency for Healthcare Research and Quality (AHRQ) were derived using hospital episode statistics for England for 2003-4, 2004-5, and 2005-6. A case-control analysis was undertaken to compare length of stay and mortality between cases (patients experiencing the particular safety event measured by an indicator) and controls matched for age, sex, health resource group (standard groupings of clinically similar treatments that use similar levels of healthcare resource), main specialty, and trust. Comparisons were undertaken with US data.Setting All NHS trusts in England.Participants Inpatients in NHS trusts.Results There was fair consistency in national rates for the nine indicators across three years. For all but one indicator, hospital stays were longer in cases than in matched controls (range 0.2-17.1 days, P