title: Appendicectomy in Western Australia: profile and trends, 1981-1997.
abstract: OBJECTIVE
  To measure and describe changes in the incidence of appendicectomy in the population of Western Australia (WA) for 1981-1997.
  
  
  METHODS
  Population-based incidence study using hospital discharge data.
  
  
  METHODS
  All hospitals in WA (1981-1997).
  
  
  METHODS
  All patients who underwent an appendicectomy in WA hospitals.
  
  
  METHODS
  Changes in the incidence of appendicectomy procedures over time; age-standardised rates and age-sex profiles of four appendicectomy subgroups: (1) acute emergency admission, (2) other emergency admission, (3) incidental appendicectomy and (4) other appendicectomy.
  
  
  RESULTS
  From 1981 to 1997, there were 59,749 appendicectomies in WA hospitals. The age-standardised rate of appendicectomy declined by 63% in metropolitan females, by 44% in non-metropolitan females, by 41% in metropolitan males and by 21% in non-metropolitan males. The rate of decline was significantly greater in females and in metropolitan patients. From 1988 to 1997, acute emergency admission for appendicectomy was the most common admission status and was more common in males than females (122 v 103 per 100,000 person-years) and in non-metropolitan areas. The rate of incidental appendicectomy was higher among females than males (20 v 7 per 100,000 person-years). From 1988 to 1997, recorded diagnosis coding for appendicitis became more specific, with a marked reduction in the use of the "unspecified" appendicitis code.
  
  
  CONCLUSIONS
  The overall incidence of appendicectomy has declined markedly in WA and includes a decline in the practice of incidental appendicectomy. The trend was greatest in the metropolitan hospitals.
authors.affiliation: Needs Assessment and Health Outcomes Unit, Central Sydney Area Health Service, NSW.
authors.forename: N J
authors.initials: NJ
authors.lastname: Donnelly
authors.forename: J B
authors.initials: JB
authors.lastname: Semmens
authors.forename: D R
authors.initials: DR
authors.lastname: Fletcher
authors.forename: C D
authors.initials: CD
authors.lastname: Holman
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D001062:Appendectomy / Q000706:statistics & numerical data* / Q000639:trends; D002648:Child; D016208:Databases, Factual; D005260:Female; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D017678:Sex Distribution; D014904:Western Australia / Q000453:epidemiology