Understanding Gastroenteritis in Middle‐aged and Older Australians
Creators: name: Chen, Yingxi
Publisher: name: The Australian National University
Year: 2017
Subjects: Gastroenteritis
Gastrointestinal infections
Epidemiology
Data linkage
Middle-aged and older adults

description: Background: Gastroenteritis is an important cause of morbidity in older adults, resulting in a significant health burden globally. The aims of this thesis were to describe the epidemiology of gastroenteritis in older adults and to investigate factors associated with hospitalisation with all-cause and cause-specific gastroenteritis in a cohort of middle-aged and older Australians. Methods: I used design-based logistic regression and proportional hazards regression to analyse two datasets: (1) a national survey of gastroenteritis in the Australian community conducted in 2008–2009; and (2) a large-scale population-based cohort of middle-aged and older Australians with data linkage to hospitalisations, pharmaceuticals, notifiable diseases and deaths data. Additionally, I conducted a systematic review and meta-analysis of Clostridium difficile infection among people with inflammatory bowel disease. Results: I estimated that 78,356 people aged ≥65 years old visited a doctor due to gastroenteritis in Australia annually, with 157,317 million courses of medication usage in one year from 2008−2009. From population-based cohort data, I demonstrated that the incidence of hospitalisation with gastroenteritis increased with older age; from 2.4 per 1,000 person-years in adults aged 45-54 years old to 9.5 per 1,000 in those aged ≥65 years. Compared to adults aged 45-54 years old, older persons had a higher incidence of hospitalisation with Salmonella infection and C. difficile infection. After adjustment, the risk of hospitalisation with gastroenteritis differed depending on sex and region of residence. Poor self-rated health and use of proton pump inhibitors (PPI) were significantly associated with gastroenteritis hospitalisation. Hospitalisation with C. difficile infection was associated with longer hospital stays, greater in-hospital costs and higher in-hospital deaths compared to hospitalisation without C. difficile infection. In a meta-analysis of six international studies included in the systematic review, C. difficile infection was a significant risk factor for colectomy among patients with inflammatory bowel disease (Odds Ratio: 1.90; 95%CI 1.23-2.93). Conclusions: This thesis demonstrates a significant burden of gastroenteritis in older Australians. Incidence of hospitalisation with all-cause and cause-specific gastroenteritis increases significantly with age. Future efforts should focus on defining and improving preventive measures for gastroenteritis hospitalisation among the elderly. The risk of hospitalisation varies by sex and region of residence, which reflects differences in exposure. PPI use is significantly associated with gastroenteritis hospitalisation. Given the widespread of PPI use, particularly among older people, clinicians should be aware of this potential association when considering PPI therapy. In addition, early recognition and supportive treatment of diarrhoea in older patients with poor self-rated health may prevent subsequent hospitalisation and improve their health outcomes