World Journal of Surgery

, Volume 36, Issue 7, pp 1527–1533 | Cite as

Laparoscopic Appendectomy Outcomes on the Weekend and During the Week are no Different: A National Study of 151,774 Patients

  • Mathias Worni
  • Truls Østbye
  • Mihir Gandhi
  • Dimple Rajgor
  • Jatin Shah
  • Anand Shah
  • Ricardo Pietrobon
  • Danny O. Jacobs
  • Ulrich GullerEmail author



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.


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.


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.


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.


Appendicitis Acute Appendicitis Pulmonary Complication Laparoscopic Appendectomy Nationwide Inpatient Sample 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



The authors thank the Research on Research Group (, last accessed 10/2011) for the research process platforms used in the preparation of our manuscript []. This work was supported by grant PBBEP3-131567 from the Swiss National Science Foundation (MW). The authors have no conflicts of interest, including specific financial interests and relationships and affiliations relevant to the subject matter or materials discussed in the manuscript) [32, 33].


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Copyright information

© Société Internationale de Chirurgie 2012

Authors and Affiliations

  • Mathias Worni
    • 1
    • 2
  • Truls Østbye
    • 3
    • 4
  • Mihir Gandhi
    • 1
    • 4
    • 5
  • Dimple Rajgor
    • 1
  • Jatin Shah
    • 1
  • Anand Shah
    • 1
  • Ricardo Pietrobon
    • 1
  • Danny O. Jacobs
    • 6
  • Ulrich Guller
    • 2
    • 7
    Email author
  1. 1.Research on Research Group, Department of SurgeryDuke University Medical CenterDurhamUSA
  2. 2.Department of Visceral Surgery and MedicineInselspital, Berne University HospitalBerneSwitzerland
  3. 3.Department of Community and Family MedicineDuke University Medical CenterDurhamUSA
  4. 4.Duke-NUS Graduate Medical SchoolSingaporeSingapore
  5. 5.Singapore Clinical Research InstituteSingaporeSingapore
  6. 6.Department of SurgeryDuke University Medical CenterDurhamUSA
  7. 7.Department of Medical Oncology & HematologyKantonal Hospital St. GallenSt. GallenSwitzerland

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