title: Unparalleled patterns of intussusception and rotavirus gastroenteritis hospitalization rates among children younger than six years in Italy.
abstract: No nationwide studies are available so far in Italy to analyze the annual trend of hospitalizations for intussusception (IS) comparing it with that of rotavirus gastroenteritis (GARV), therefore a survey was undertaken to assess the incidence rates of IS and GARV in children hospitalized between 2005 and 2014 in Italy.
  
  
  
  A retrospective observational study was conducted analyzing the Italian Hospital Discharge Database (HDD), including a study on all hospitalizations bearing a primary or secondary diagnoses coded as 560.0 along the decade 2005-2014.
  
  
  
  The trend and seasonality of hospitalizations rates (HRs) for IS were analyzed stratifying by gender and age groups. The statistical significance of temporal trend was determined using the analysis of the slope of the regression line. For the same period, data related to national hospitalizations for GARV (code 008.61 in any diagnosis) were analyzed for comparative purpose.
  
  
  
  A total of 6,074 hospitalizations for IS in children aged <6 years were recorded. A statistically significant increase of HRs was seen for male, female, 12-23 months and 24-71 months age groups. However, in children within the first year of life there was a downward trend. The analysis of the distribution of the HRs by months of hospitalization showed the absence of seasonality, in contrast to HRs for GARV.
  
  
  
  Our analysis confirmed the occurrence of the incidence peak of IS hospitalizations in children aged seven months. HRs decreased after the first year of life, replicating an age distribution that is also observed for other paediatric infectious diseases. Nevertheless, the total trend of HR was increasing. In Italy, IS HRs in the pre-vaccination era resulted in line with those described for other European countries, with an increasing trend and the annual slope of IS hospitalization turned out to unparallel the GARV HRs.
authors.affiliation: Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Mattei
authors.affiliation: Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Fiasca
authors.affiliation: Department of Life, Health and Environmental Sciences, University of L'Aquila, L'Aquila, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Mazzei
authors.affiliation: Department of Maternal and Child Health, Local Health Unit of Rieti, Rieti, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Sbarbati
mesh_terms: D002648:Child; D002675:Child, Preschool; D005260:Female; D005759:Gastroenteritis / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology* / Q000821:virology; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007443:Intussusception / Q000175:diagnosis* / Q000453:epidemiology* / Q000821:virology; D007558:Italy / Q000453:epidemiology; D008297:Male; D010351:Patient Discharge / Q000706:statistics & numerical data; D012008:Recurrence; D012189:Retrospective Studies; D012307:Risk Factors; D012401:Rotavirus / Q000302:isolation & purification; D012400:Rotavirus Infections / Q000150:complications / Q000175:diagnosis* / Q000453:epidemiology*
keywords: Children; Hospitalization rates; Intestinal invagination; Intussusception; Rotavirus