title: The effect of hospital volume of pediatric appendectomies on the misdiagnosis of appendicitis in children.
abstract: BACKGROUND
  Although appendicitis is a common pediatric surgical condition, it is often misdiagnosed. Because higher hospital volume has been associated with improved outcome for many surgical procedures, the current study investigates whether hospital volume of pediatric appendectomies is associated with misdiagnosis of appendicitis in children.
  
  
  METHODS
  The Kids' Inpatient Database is a national sample of pediatric discharges from 2521 hospitals in 22 states in 1997. In this study, misdiagnosis was defined as a patient with a principal International Classification of Diseases, Ninth Revision procedure code for nonincidental appendectomy without a corresponding diagnosis code for appendicitis. Hospitals were stratified into 5 groups based on the number of nonincidental appendectomies performed on children in 1997: lowest (<1 per month), low (>or=1 per month but <1 per week), medium (1-2 per week), high (2-3 per week), and highest (>or=3 per week). Using generalized estimating equations to control for clustering within hospitals, we developed a logistic regression model of the effect of hospital volume on misdiagnosis while adjusting for patient age, gender, race, and insurance status.
  
  
  RESULTS
  In the database, 37,109 nonincidental appendectomies were performed on children 1 to 18 years old in 1997. Of those, 3103 (8.4%) were misdiagnosed. Of all appendectomies, 24,655 (66.4%) were performed at lowest- or low-volume hospitals. After adjusting for patient characteristics, lowest- (odds ratio [OR]: 1.5; 95% confidence interval [CI]: 1.0-2.2) and low- (OR: 1.6; 95% CI: 1.1-2.3) volume hospitals had a significantly increased likelihood of misdiagnosis compared with highest-volume hospitals. Misdiagnosis at medium- (OR: 1.5; 95% CI: 1.0-2.2) and high- (OR: 1.4; 95% CI: 0.9-2.2) volume hospitals was similar to misdiagnosis at lower-volume hospitals, although not statistically different from highest-volume hospitals.
  
  
  CONCLUSIONS
  Almost two thirds of pediatric appendectomies are performed at hospitals performing <1 pediatric appendectomy per week. Lower hospital volume of pediatric appendectomies is associated with a significantly increased likelihood of misdiagnosis of appendicitis in children.
authors.affiliation: Harvard Pediatric Health Services Research Fellowship, Department of Surgery, Children's Hospital Boston, Boston, Massachusetts 02115, USA.
authors.forename: Douglas S
authors.initials: DS
authors.lastname: Smink
authors.forename: Jonathan A
authors.initials: JA
authors.lastname: Finkelstein
authors.forename: Ken
authors.initials: K
authors.lastname: Kleinman
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Fishman
mesh_terms: D000293:Adolescent; D001062:Appendectomy / Q000706:statistics & numerical data*; D001064:Appendicitis / Q000175:diagnosis* / Q000601:surgery; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D016208:Databases, Factual; D003953:Diagnosis-Related Groups; D003951:Diagnostic Errors / Q000706:statistics & numerical data*; D005260:Female; D006776:Hospitals, Pediatric / Q000706:statistics & numerical data*; D006784:Hospitals, Teaching / Q000706:statistics & numerical data; D006801:Humans; D007223:Infant; D016015:Logistic Models; D008297:Male; D016017:Odds Ratio; D017063:Outcome Assessment, Health Care; D012189:Retrospective Studies; D014481:United States