Seasonal variation in emergency general surgery

Bardiya Zangbar, Peter Rhee, Viraj Pandit, Chiu Hsieh Hsu, Mazhar Khalil, Terence OKeeffe, Leigh Neumayer, Bellal Joseph

Research output: Contribution to journalArticlepeer-review

40 Scopus citations


Objective: The aim of this study was to assess the seasonal variation in emergency general surgery (EGS) admissions. Background: Seasonal variation in medical conditions is well established; however, its impact on EGS cases remains unclear. Methods: The National Inpatient Sample (NIS) database was queried over an 8-year period (2004-2011) for all patients with diagnosis of acute appendicitis, acute cholecystitis, and diverticulitis. Elective admissions were excluded. The following data for each admission were recorded: age, sex, race, admission month, major operative procedure, hospital region, and mortality. Seasons were defined as follows: Spring (March, April, May), Summer (June, July, August), Fall (September, October, November), and Winter (December, January, February). X11 procedure and spectral analysis were performed to confirm seasonal variation. Results: A total of 63,911,033 admission records were evaluated of which 493,569 were appendicitis, 395,838 were cholecystitis, and 412,163 were diverticulitis. Seasonal variation is confirmed in EGS (F=159.12, P<0.0001) admissions. In the subanalysis, seasonal variation was found in acute appendicitis (F=119.62, P<0.0001), acute cholecystitis (F=37.13, P<0.0001), and diverticulitis (F=69.90, P<0.0001). The average monthly EGS admission in Winter was 11,322±674. The average monthly EGS admission in Summer was higher than that of Winter by 13.6% (n=1542;95% CI: 1180-1904, P<0.001). Conclusions: Hospitalization due to EGS adheres to a consistent cyclical pattern, with more admissions occurring during the Summer months. Although the reasons for this variability are unknown, this information may be useful for hospital resource reallocation and staffing.

Original languageEnglish (US)
Pages (from-to)76-81
Number of pages6
JournalAnnals of surgery
Issue number1
StatePublished - 2016
Externally publishedYes


  • Acute appendicitis
  • Acute cholecystitis
  • Diverticulitis
  • Emergency general surgery
  • National Inpatient Sample
  • Regression
  • Spectral analysis

ASJC Scopus subject areas

  • Surgery


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