title: Changes in adverse event rates in hospitals over time: a longitudinal retrospective patient record review study.
abstract: OBJECTIVE
  To determine the change in adverse event (AE) rates and preventable AE rates over time, identify certain patient risk groups and discuss factors influencing the outcome.
  
  
  METHODS
  Longitudinal retrospective patient record review study.
  
  
  METHODS
  A random sample of 21 hospitals in The Netherlands in 2004, and 20 hospitals in 2008. In each hospital, 400 patient admissions were included in 2004, and 200 in 2008.
  
  
  METHODS
  AEs and preventable AEs.
  
  
  RESULTS
  Multilevel analyses of 11 883 patient records (7.887 in 2004, 3.996 in 2008) showed that the rate of patients experiencing an AE increased from 4.1% (95% CI 3.3% to 5.1%) in 2004 to 6.2% (95% CI 5.0% to 7.6%) in 2008. The preventable AE rate remained relatively stable at 1.8% (95% CI 1.3% to 2.4%) in 2004 and 1.6% (95% CI 1.2% to 2.3%) in 2008. The risk of experiencing a preventable AE was increasingly higher for patients admitted to a surgical unit (OR 1.54 (95% CI 1.10 to 2.16) in 2004 and 3.32 (95% CI 2.17 to 5.07)) in 2008. More than 50% of all AEs were related to surgery. Indications were found that differences in the risk of experiencing a preventable AE between hospital departments were larger in 2008 than in 2004, while differences between hospitals themselves were smaller.
  
  
  CONCLUSIONS
  Patient harm related to healthcare is a persistent problem that is hard to influence. Measuring AEs over time stresses the continuing urgency, and also identifies possible areas for improvement.
authors.affiliation: Department of Public and Occupation Health,EMGO+ Institute/VU University Medical Center, Van der Boechorststraat 7, room B-550, Amsterdam 1081 BT, The Netherlands. r.baines@vumc.nl
authors.forename: Rebecca J
authors.initials: RJ
authors.lastname: Baines
authors.forename: Maaike
authors.initials: M
authors.lastname: Langelaan
authors.forename: Martine C
authors.initials: MC
authors.lastname: de Bruijne
authors.forename: Henk
authors.initials: H
authors.lastname: Asscheman
authors.forename: Peter
authors.initials: P
authors.lastname: Spreeuwenberg
authors.forename: Lotte
authors.initials: L
authors.lastname: van de Steeg
authors.forename: Kitty M
authors.initials: KM
authors.lastname: Siemerink
authors.forename: Floor
authors.initials: F
authors.lastname: van Rosse
authors.forename: Maren
authors.initials: M
authors.lastname: Broekens
authors.forename: Cordula
authors.initials: C
authors.lastname: Wagner
mesh_terms: D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D019300:Medical Errors / Q000517:prevention & control / Q000706:statistics & numerical data*; D008499:Medical Records / Q000706:statistics & numerical data*; D008508:Medication Errors / Q000517:prevention & control / Q000706:statistics & numerical data; D008875:Middle Aged; D009426:Netherlands; D061214:Patient Safety; D011785:Quality Assurance, Health Care; D012189:Retrospective Studies; D013514:Surgical Procedures, Operative / Q000009:adverse effects*