title: Cyclical increase in diverticulitis during the summer months.
abstract: OBJECTIVE
  We hypothesized that the rate of nonelective hospital admissions for diverticulitis conforms to seasonal variation.
  
  
  METHODS
  Retrospective cohort analysis.
  
  
  METHODS
  Patients admitted to hospitals in the Nationwide Inpatient Sample, a 20% sample of US community hospitals.
  
  
  METHODS
  We identified patients with a nonelective admission or discharge for diverticulitis from January 1, 1997, through December 31, 2005, and determined the proportion of diverticulitis admissions (standardized to all inpatient admissions) for a particular admission month or discharge quarter. Next, we analyzed the potential effects of region, age, sex, and race on excess seasonal admissions for diverticulitis.
  
  
  RESULTS
  On average, total nonelective admissions for diverticulitis were lowest in February (23 744 admissions) and highest in August (29 733 admissions), a 25.2% increase in cases. Similarly, diverticulitis discharges increased by 14.3% during the third quarter compared with the first (P < .001). A significant seasonal pattern of diverticulitis admissions was identified that conformed to a major sinusoidal component (P < .001). The excess seasonal burden of nonelective diverticulitis admissions in the third quarter was noted across US census regions, age, sex, and race.
  
  
  CONCLUSIONS
  Hospitalization for diverticulitis adheres to a sinusoidal pattern, with more nonelective admissions occurring during the summer months. The excess summer burden of diverticulitis is noted across US census regions, age, sex, and race. A more thorough understanding of these trends may provide a mechanism to identify a potential trigger for diverticulitis.
authors.affiliation: Department of Colon and Rectal Surgery, Lahey Clinic, Tufts University, 41 Mall Road, Burlington, MA 01805, USA. rocco.ricciardi@lahey.org
authors.forename: Rocco
authors.initials: R
authors.lastname: Ricciardi
authors.forename: Patricia L
authors.initials: PL
authors.lastname: Roberts
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Read
authors.forename: Peter W
authors.initials: PW
authors.lastname: Marcello
authors.forename: Jason F
authors.initials: JF
authors.lastname: Hall
authors.forename: David J
authors.initials: DJ
authors.lastname: Schoetz
authors.forename: Eugene F
authors.initials: EF
authors.lastname: Foley
mesh_terms: D000328:Adult; D015331:Cohort Studies; D016208:Databases, Factual; D004238:Diverticulitis / Q000175:diagnosis* / Q000453:epidemiology* / Q000601:surgery; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D010343:Patient Admission / Q000706:statistics & numerical data; D012189:Retrospective Studies; D012621:Seasons; D014481:United States / Q000453:epidemiology