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Patient Safety Methodology 2007
(20032005 MedPAR Data)
To help consumers evaluate and compare hospital patient safety performance, HealthGrades analyzed patient data
for virtually every hospital in the country to determine patient safety outcomes.
HealthGrades used Medicare inpatient data from the MedPAR database (purchased from the Centers for Medicare
and Medicaid Services; 2003 through 2005 data) and Patient Safety Indicator software (QI Windows Software,
Version 3.0a) from the Agency for Healthcare Research and Quality (AHRQ) to analyze the following 13 patient
safety indicators (PSI). Major changes to the indicators in the most recent version of software are outlined in
Prevention of death in procedures where mortality is usually very low
Lack of pressure sores or bed sores acquired in the hospital
Ability to diagnose and treat in time
Absence of foreign body left in during procedure
Avoidance of collapsed lung due to a procedure or surgery in or around the chest
Lack of infections acquired at the hospital
Absence of hip fracture after surgery
Avoidance of excessive bruising or bleeding as a consequence of a procedure or surgery
Adequate organ function and electrolyte and fluid imbalance after surgery
Avoidance of respiratory failure following surgery
Lack of deep blood clots in the lungs or legs after surgery
Avoidance of severe infection following surgery
Lack of surgical wound site breakdown
For most indicators, the AHRQ software uses advanced statistical algorithms that can predict the number of patient
safety incidences likely to occur at a hospital based on the mix of types of cases treated at that hospital. For those
indicators without predicted results from the AHRQ software, predicted results were generated by grouping the
populations according to risk, and assigning average group values to patients in each group. This information is
used, in part, to determine a HealthGrades overall patient safety rating for a hospital as well as an individual
rating for each patient safety indicator.