title: Laparoscopic appendectomy outcomes on the weekend and during the week are no different: a national study of 151,774 patients.
abstract: BACKGROUND
  The "weekend effect" is defined as increased morbidity and mortality for patients admitted on weekends compared with weekdays. It has been observed for several diseases, including myocardial infarction and renal insufficiency; however, it has not yet been investigated for laparoscopic appendectomy in acute appendicitis-one of the most prevalent surgical diagnoses.
  
  
  METHODS
  The present study is based on the Nationwide Inpatient Sample (NIS) from 1999 to 2008. The following outcomes were compared between patients undergoing laparoscopic appendectomy for acute appendicitis admitted on weekdays versus weekends: severity of appendicitis, intraoperative and postoperative complications, conversion rate, in-hospital mortality, and length of hospital stay. Unadjusted and risk-adjusted generalized linear regression analyses were performed.
  
  
  RESULTS
  Overall, 151,774 patients were included, mean age was 39.6 years, 52.6% (n = 79,801) were male, and 25.3% (n = 38,317) were admitted on weekends. After risk adjustment, the conversion rate was lower [odds ratio (OR): 0.94, p = 0.004, number needed to harm (NNH): 244], whereas pulmonary complications (OR: 1.12, p = 0.028, NNH: 649) and reoperations (OR: 1.21, p = 0.013, NNH: 1,028) were slightly higher on weekends than on weekdays. Overall postoperative complications (OR: 1.03, p = 0.24), mortality (OR: 1.37, p = 0.075) and length of hospital stay (mean on weekday: 2.00 days, weekends: 2.01 days, p = 0.29) were not statistically different.
  
  
  CONCLUSIONS
  The present investigation provides evidence that no clinically significant "weekend effect" for patients undergoing laparoscopic appendectomy exists. Therefore, hospital or staffing policy changes are not justified based on the findings from this large national study.
authors.affiliation: Research on Research Group, Department of Surgery, Duke University Medical Center, Durham, NC, USA.
authors.forename: Mathias
authors.initials: M
authors.lastname: Worni
authors.forename: Truls
authors.initials: T
authors.lastname: Østbye
authors.forename: Mihir
authors.initials: M
authors.lastname: Gandhi
authors.forename: Dimple
authors.initials: D
authors.lastname: Rajgor
authors.forename: Jatin
authors.initials: J
authors.lastname: Shah
authors.forename: Anand
authors.initials: A
authors.lastname: Shah
authors.forename: Ricardo
authors.initials: R
authors.lastname: Pietrobon
authors.forename: Danny O
authors.initials: DO
authors.lastname: Jacobs
authors.forename: Ulrich
authors.initials: U
authors.lastname: Guller
mesh_terms: D000328:Adult; D001062:Appendectomy / Q000009:adverse effects / Q000706:statistics & numerical data*; D001064:Appendicitis / Q000601:surgery*; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D007431:Intraoperative Complications; D010535:Laparoscopy / Q000706:statistics & numerical data; D007902:Length of Stay; D008297:Male; D008875:Middle Aged; D011183:Postoperative Complications; D012044:Regression Analysis; D012720:Severity of Illness Index; D013997:Time Factors; D014481:United States