title: Adverse events in New Zealand public hospitals I: occurrence and impact.
abstract: OBJECTIVE
  To assess the occurrence and impact of adverse events in New Zealand public hospitals.
  
  
  METHODS
  Two-stage retrospective review of 6579 medical records, selected by systematic list sample from admissions for 1998 in 13 generalist hospitals providing acute care. After initial screening, medical records were reviewed by trained medical practitioners using a standardised protocol.
  
  
  RESULTS
  Except for hospital stay, the sample appeared to be closely representative of New Zealand public hospital admissions for 1998 on key demographic and clinical criteria. The proportion of hospital admissions associated with an adverse event was 12.9% (incidence rate, 11.2%), of which nearly one fifth had occurred outside a public hospital (mainly doctor s rooms, patient s home, rest home, or private hospital). Most adverse events had minor patient impact, with less than 15% associated with permanent disability or death. Hospital workload was strongly affected, however, with adverse events adding an average of over nine days (median 4 days) to the expected hospital stay. There was limited evidence of patterning by diagnostic category. The elderly were disproportionately affected.
  
  
  CONCLUSIONS
  The study provides representative base parameters that can contribute to the wider understanding, and potential improvement, of patient safety and the quality of care in New Zealand public hospitals.
authors.affiliation: Department of Public Health and General Practice, Christchurch School of Medicine, University of Otago, Christchurch, New Zealand. peter.davis@chmeds.ac.nz
authors.forename: Peter
authors.initials: P
authors.lastname: Davis
authors.forename: Roy
authors.initials: R
authors.lastname: Lay-Yee
authors.forename: Robin
authors.initials: R
authors.lastname: Briant
authors.forename: Wasan
authors.initials: W
authors.lastname: Ali
authors.forename: Alastair
authors.initials: A
authors.lastname: Scott
authors.forename: Stephan
authors.initials: S
authors.lastname: Schug
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002648:Child; D002675:Child, Preschool; D005006:Ethnicity; D005260:Female; D006760:Hospitalization; D006779:Hospitals, Public / Q000706:statistics & numerical data*; D006801:Humans; D007049:Iatrogenic Disease; D007223:Infant; D008297:Male; D008485:Medical Audit; D019300:Medical Errors / Q000401:mortality / Q000706:statistics & numerical data*; D008875:Middle Aged; D009520:New Zealand / Q000453:epidemiology; D012189:Retrospective Studies; D012494:Sampling Studies