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 outcome
