Estimating the Burden of Medically Attended Norovirus Gastroenteritis: Modeling Linked Primary Care and Hospitalization Datasets

Norovirus is the leading cause of community-acquired and nosocomial acute gastroenteritis. Routine testing for norovirus is seldom undertaken and diagnosis is mainly based on presenting symptoms. This makes understanding the burden of medically-attended norovirus-attributable gastroenteritis (MA-NGE) and targeting care and prevention strategies challenging. We used linked population-based health care datasets (Clinical Practice Research Datalink General Practice OnLine Database linked with Hospital Episode Statistics Admitted Patient Care) to model the incidence of MA-NGE associated with primary care consultations or hospitalisations according to age groups in England in the period July 2007 - June 2013. Mean annual incidence rates of MA-NGE were 4.9/1,000 person-years and 0.7/1,000 person-years for episodes involving primary care or hospitalisations, respectively. Incidence rates were highest in children younger than 5 years of age: 34.0 consultations/1,000 person-years and 3.3 hospitalisations/1,000 person-years. MA-NGE hospitalisation rates were second highest in adults aged 65 years and older (1.7/1,000 person-years). In this particular study, the burden of MA-NGE estimated from healthcare datasets was higher than previously estimated in small cohort studies in England. Routinely collected primary care and hospitalisation datasets are useful resources to estimate and monitor the burden of MA-NGE in a population over time.