title: Hospital-based, prospective, multicentre surveillance to determine the incidence of intussusception in children aged below 15 years in Germany.
abstract: BACKGROUND
  A new vaccine against Rotavirus (RV) gastroenteritis was introduced in Germany in 2006. In 1997 the first RV vaccine was withdrawn due to an increased incidence in intussusception (IS). Thus, an accurate estimation of the incidence of IS is important for post-licensure surveillance.
  
  
  METHODS
  IS-Data were obtained from the 'Erhebungseinheit für seltene pädiatrische Erkrankungen Deutschland' (ESPED, German surveillance unit for rare pediatric diseases) collaborations' central register where all cases of intussusception in Germany for the years 2006 and 2007 are collected (n = 1200). In order to obtain an unbiased estimate of the incidence, it is necessary to determine the population under risk out of which these cases originated, and the proportion of real cases not reported to the registry (underreporting). In order to assess underreporting, a random sample of 31 hospitals was re-assessed by an outside reviewer. The estimation of incidence was done using a single Maximum-Likelihood (ML) estimator based on data from both the registry and the sample.
  
  
  RESULTS
  The uncorrected observed incidence was calculated to be 26.6/100,000 child-years for children below 1 year old, 23.8 for those below 2 years old, and 5.2 for those below 15 years old. The review revealed a mean reporting quota of about 41% and the ML approach yielded an incidence of 51.5/100,000 child-years (95%CI [41.7;61.1]) for children below 2 years of age.
  
  
  CONCLUSIONS
  While substantial under-reporting led to very conservative estimates of the IS incidence, the approach described here allows an accurate estimation of IS incidence including corresponding confidence bands. Therefore, ML estimation is a straightforward instrument to derive stable, unbiased estimates in epidemiological studies with incomplete data.
authors: University of Bochum, Fakultät für Mathematik, D-44780 Bochum, Germany.
authors: Nicolai
authors: N
authors: Bissantz
authors: Andreas C
authors: AC
authors: Jenke
authors: Matthias
authors: M
authors: Trampisch
authors: Renate
authors: R
authors: Klaassen-Mielke
authors: Kathrin
authors: K
authors: Bissantz
authors: Hans-Joachim
authors: HJ
authors: Trampisch
authors: Tim
authors: T
authors: Holland-Letz
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D005759:Gastroenteritis / Q000453:epidemiology / Q000517:prevention & control*; D005858:Germany / Q000453:epidemiology; D006801:Humans; D015994:Incidence; D007223:Infant; D007231:Infant, Newborn; D007443:Intussusception / Q000453:epidemiology* / Q000209:etiology*; D008297:Male; D011446:Prospective Studies; D012400:Rotavirus Infections / Q000517:prevention & control*; D022243:Rotavirus Vaccines / Q000008:administration & dosage / Q000009:adverse effects*
chemical_list: D022243:Rotavirus Vaccines