Diverging Trends in Gastroenteritis Hospitalizations During 2 Decades in Western Australian Aboriginal and Non-Aboriginal Children

Background: Gastroenteritis is a major cause of pediatric morbidity. We describe temporal, spatial and seasonal trends in age-specific gastroenteritis hospitalizations among Aboriginal and non-Aboriginal Australian children during 2 decades, providing a baseline to evaluate the impact of a rotavirus vaccine program begun in 2007. Methods: We conducted a population-based, data linkage study of Aboriginal and non-Aboriginal births in Western Australia, 1983 to 2006, and analyzed gastroenteritis-coded hospitalizations before age 15 years in the cohort of 596,465 births. Hospitalization rates in Aboriginal and non-Aboriginal children and between geographical regions were compared between 1983 to 1994 and 1995 to 2006. Results: Gastroenteritis rates were highest in children 6-11 months of age (Aboriginal: 259.3/1000/annum; non-Aboriginal: 22.7/1000/annum). Rates declined in Aboriginal children between 1983 to 1994 and 1995 to 2006, particularly in those 12-17 months of age (309/1000 to 179/1000). Rates in non-Aboriginal children <5 years increased 10-40%. The disparity for gastroenteritis rates between Aboriginal and non-Aboriginal children <5 years declined from being 15.4 times higher to 7.6 times higher in those aged 12-17 months and from 8.4 to 4.4 in those aged 2-4 years. Rates were highest in rural and remote regions, and diverging temporal trends were seen in different geographical regions. Seasonality varied between Aboriginal and non-Aboriginal children and climatic zones. Conclusions: This is the largest study of gastroenteritis hospitalization trends in children. We found diverging trends of gastroenteritis hospitalization rates in Aboriginal and non-Aboriginal children. Although rates have declined in Aboriginal children, disparity between Aboriginal and non-Aboriginal children continues. Our findings highlight the need to consider age, ethnicity, seasonality and climate when evaluating rotavirus vaccine programs.