title: Volume-outcome relation for acute appendicitis: evidence from a nationwide population-based study.
abstract: BACKGROUND
  Although procedures like appendectomy have been studied extensively, the relative importance of each surgeon's surgical volume-to-ruptured appendicitis has not been explored. The purpose of this study was to investigate the rate of ruptured appendicitis by surgeon-volume groups as a measure of quality of care for appendicitis by using a nationwide population-based dataset.
  
  
  METHODS
  We identified 65,339 first-time hospitalizations with a discharge diagnosis of acute appendicitis (International Classification of Disease, Ninth Revision, Clinical Modification (ICD-9-CM) codes 540, 540.0, 540.1 and 540.9) between January 2007 and December 2009. We used "whether or not a patient had a perforated appendicitis" as the outcome measure. A conditional (fixed-effect) logistic regression model was performed to explore the odds of perforated appendicitis among surgeon case volume groups.
  
  
  RESULTS
  Patients treated by low-volume surgeons had significantly higher morbidity rates than those treated by high-volume (28.1% vs. 26.15, p<0.001) and very-high-volume surgeons (28.1% vs. 21.4%, p<0.001). After adjusting for surgeon practice location, and teaching status of practice hospital, and patient age, gender, and Charlson Comorbidity Index, and hospital acute appendicitis volume, patients treated by low-volume surgeons had significantly higher rates of perforated appendicitis than those treated by medium-volume surgeons (OR = 1.09, p<0.001), high-volume surgeons (OR = 1.16, p<0.001), or very-high-volume surgeons (OR = 1.54, p<0.001).
  
  
  CONCLUSIONS
  Our study suggested that surgeon volume is an important factor with regard to the rate of ruptured appendicitis.
authors.affiliation: Division of General Surgery, Department of Surgery, Taipei Medical University Hospital, Taipei, Taiwan.
authors.forename: Po-Li
authors.initials: PL
authors.lastname: Wei
authors.forename: Shih-Ping
authors.initials: SP
authors.lastname: Liu
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Keller
authors.forename: Herng-Ching
authors.initials: HC
authors.lastname: Lin
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001062:Appendectomy / Q000706:statistics & numerical data*; D001064:Appendicitis / Q000150:complications / Q000601:surgery*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012044:Regression Analysis; D012421:Rupture / Q000150:complications; D013624:Taiwan; D016896:Treatment Outcome