title: Investigating Adverse Event Free Admissions in Medicare Inpatients as a Patient Safety Indicator.
abstract: To investigate adverse event free admissions as a potential, patient-centered indicator aligned directly with the goal of patient safety-freedom from harm.
  
  
  
  Preventable adverse event rates in healthcare could be further reduced. These are generally measured separately, one adverse event at a time. However, this does not reveal whether different patients are affected or the same patients are experiencing multiple events.
  
  
  
  We examined Medicare inpatient hospital administrative datasets for 2009 to 2011, processed using standard criteria. Events were (i) death within 30 days, (ii) unplanned readmissions within 30 days, (iii) long length of stay, (iv) healthcare acquired infections, and (v) established patient safety indicators not present on admission. We defined adverse event free admissions as those without record of any of these events. National rates were calculated by diagnosis group. Risk-adjusted hospital-specific rates of adverse event free admissions were calculated using colorectal procedures as an example.
  
  
  
  There were 23,991,193 admissions after exclusions. Approximately, 64% went through the acute inpatient Medicare system without record of anything untoward. Multiple events were recorded in 22·7% admissions; 15% of these experienced more than 2 adverse events. Risk-adjusted hospital-specific rates of adverse event free admissions for colorectal procedures showed 131 out of 3786 hospitals below the 99·8% lower control limit of the national upper quartile.
  
  
  
  Overall, only 60% of admissions were recorded as adverse event free. Multiple adverse events were common. Even if events are under recorded, this measure could provide an easily understandable and useful baseline for clinicians and managers.
authors.affiliation: *Department of Primary Care and Public Health, Dr Foster Unit at Imperial College London, London, UK †Department of Surgery and Cancer, Imperial College London, St Mary's Hospital, London, UK.
authors.forename: Alice
authors.initials: A
authors.lastname: King
authors.forename: Alex
authors.initials: A
authors.lastname: Bottle
authors.forename: Omar
authors.initials: O
authors.lastname: Faiz
authors.forename: Paul
authors.initials: P
authors.lastname: Aylin
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003107:Colorectal Surgery / Q000009:adverse effects* / Q000379:methods; D003430:Cross-Sectional Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D007297:Inpatients / Q000706:statistics & numerical data; D008297:Male; D006278:Medicare / Q000191:economics / Q000706:statistics & numerical data*; D017063:Outcome Assessment, Health Care; D010343:Patient Admission / Q000706:statistics & numerical data; D010359:Patient Readmission / Q000706:statistics & numerical data*; D011183:Postoperative Complications / Q000175:diagnosis* / Q000628:therapy; D019984:Quality Indicators, Health Care; D012189:Retrospective Studies; D018570:Risk Assessment; D006113:United Kingdom; D014481:United States