IDDF2018-ABS-0034 High age-specific prevalence of inflammatory bowel disease amongst the elderly in the city of canada bay area, sydney: a metropolitan, population-based study

Background Knowledge of Inflammatory Bowel Disease (IBD) prevalence allows health care administrators to understand disease burden and appropriately plan for research and medical care. Young IBD subjects often migrate from rural to urban areas for education and work opportunities, necessitating metropolitan prevalence studies to reduce under-representation. Also, the impact of urbanisation on IBD prevalence requires further exploration. Unlike IBD incidence, where young age-groups dominate, we hypothesised that the elderly age-groups would have the highest IBD prevalence given mortality rates being equivalent to the general population. We aimed to determine the first IBD prevalence rates for New South Wales, Australia. Methods This was an observational, population-based epidemiological study which captured disease information of people living with IBD within the metropolitan City of Canada Bay Local Government Area on the 1st of January 2016. The diagnosis was according to the Copenhagen Criteria. Age-standardisation was according to the WHO Standard Population. Results We identified 330 cases of IBD (49.1% male, median age 47, IQR=27, crude point prevalence rate of 371.5 per 100,000). Full diagnostic confirmation was achieved in 100%. The age-standardised point prevalence rate was 359.2 per 1 00 000. The crude point prevalence rates were 167.8, 158.8 and 45.0 per 1 00 000 for Crohn’s disease (CD), ulcerative colitis (UC) and IBD Unspecified (IBDU), respectively. The age-standardised rates were 171.6, 148.1 and 39.5 per 1 00 000 for CD, UC, and IBDU respectively. IBD prevalence steadily increased with age, peaking at 1061 per 1 00 000 in patients older than 85 years. A trend was observed between prevalence and socioeconomic status between suburbs. Conclusions Sydney exhibited the highest prevalence of IBD in Australasia. The extrapolated estimate for Australia was 89 000 people with IBD. Higher socioeconomic status and urbanisation may be contributing factors. The ageing IBD population accounts for the highest prevalence, peaking at greater than 1000 per 1 00 000. Safer therapies, cancer screening strategies and greater attention towards comorbidities are therefore of increasing importance in managing IBD patients.