Inflammatory bowel disease incidence, prevalence and 12-month initial disease course in Tasmania, Australia.

BACKGROUND: High inflammatory bowel disease (IBD) rates have been reported in Australasia, but no state-wide studies have yet been performed. AIM: This study estimates the 1-year incidence and point prevalence of IBD in the state of Tasmania, Australia. It also reports clinical outcomes after 12 months of diagnosis in an incident cohort. METHODS: A prospective, population-based study was performed collecting prevalent and incident state-wide cases from 1 June 2013 to 31 May 2014. Case data were identified from specialist doctors, pathology databases and hospital records. Age-standardised rates (ASR) were calculated based on World Health Organization 2000 standard population characteristics. Incident cases were followed up 12 months after diagnosis. RESULTS: There were 1719 prevalent cases: ASR for IBD, Crohn disease (CD), ulcerative colitis (UC) and inflammatory bowel disease unclassified (IBDU) prevalence rates were 303.9, 165.5, 131.4 and 6.9 per 100 000 respectively. Prevalent CD cases were younger, with greater immunomodulator/biological use and bowel resections. There were 149 incident cases: ASR for IBD, CD, UC and IBDU incidence were 29.5, 15.4, 12.4 and 1.7 per 100 000 respectively. Incident CD cases were more likely than UC or IBDU to require escalation of medical therapy, hospitalisation and bowel resection, especially among those with penetrating or stricturing disease. They had a longer duration of symptoms prior to diagnosis. CONCLUSION: IBD prevalence and incidence rates are high in Tasmania, comparable to data from other Australasian studies and those from Northern Europe and America. Poorer 12-month clinical outcomes occurred in complicated CD, with greater use of healthcare resources.

Nonsynonymous Polymorphism in Guanine Monophosphate Synthetase Is a Risk Factor for Unfavorable Thiopurine Metabolite Ratios in Patients With Inflammatory Bowel Disease.

Background: Up to 20% of patients with inflammatory bowel disease (IBD) who are refractory to thiopurine therapy preferentially produce 6-methylmercaptopurine (6-MMP) at the expense of 6-thioguanine nucleotides (6-TGN), resulting in a high 6-MMP:6-TGN ratio (>20). The objective of this study was to evaluate whether genetic variability in guanine monophosphate synthetase (GMPS) contributes to preferential 6-MMP metabolizer phenotype. Methods: Exome sequencing was performed in a cohort of IBD patients with 6-MMP:6-TGN ratios of >100 to identify nonsynonymous single nucleotide polymorphisms (nsSNPs). In vitro assays were performed to measure GMPS activity associated with these nsSNPs. Frequency of the nsSNPs was measured in a cohort of 530 Caucasian IBD patients. Results: Two nsSNPs in GMPS (rs747629729, rs61750370) were detected in 11 patients with very high 6-MMP:6-TGN ratios. The 2 nsSNPs were predicted to be damaging by in silico analysis. In vitro assays demonstrated that both nsSNPs resulted in a significant reduction in GMPS activity (P < 0.05). The SNP rs61750370 was significantly associated with 6-MMP:6-TGN ratios ≥100 (odds ratio, 5.64; 95% confidence interval, 1.01-25.12; P < 0.031) in a subset of 264 Caucasian IBD patients. Conclusions: The GMPS SNP rs61750370 may be a reliable risk factor for extreme 6MMP preferential metabolism.

Never underestimate inflammatory bowel disease: High prevalence rates and confirmation of high incidence rates in Australia.

BACKGROUND AND AIMS: Regional variations in inflammatory bowel disease (IBD) rates have been observed. Limited epidemiological data are available from Australasia. IBD prevalence rates have never been assessed in an Australian population-based setting. In addition, there are few historical IBD incidence data to allow assessment of rate changes. The aims were to calculate Australia's first population-based IBD prevalence rates, to reassess local IBD incidence rates, and to establish a population-based inception cohort. METHODS: An observational, prospective population-based epidemiological study was performed to assess IBD prevalence and incidence rates from July 2010 to June 2011 in a geographically defined Australian population (Barwon, Victoria). RESULTS: There were 1011 prevalent IBD cases identified, representing a crude point prevalence rate of 344.6 per 100,000 on June 30, 2011. Crohn's disease was the most common prevalent subtype. Seventy-one incident cases of IBD were identified, with a crude incidence rate of 24.2 per 100,000. Crohn's disease was again more common. Local incidence rates have not changed between 2007 and the present study. All incident cases were successfully incorporated into an inception cohort. CONCLUSION: The burden of IBD in our local region is high. Demographic similarities allow these results to be applied to the broader Australian community. We propose that the number of existing and new cases each year in Australia has been previously underestimated. These revised figures will be important when planning the provision of health resources for these patients in the future and when assessing need for research funding priorities.

Health Care Cost Analysis in a Population-based Inception Cohort of Inflammatory Bowel Disease Patients in the First Year of Diagnosis.

BACKGROUND: There are limited prospective population-based data on the health care cost of IBD in the post-biologicals era. A prospective registry that included all incident cases of inflammatory bowel disease [IBD] was established to study disease progress and health cost. AIM: To prospectively assess health care costs in the first year of diagnosis among a well-characterised cohort of newly diagnosed IBD patients. METHOD: Incident cases of IBD were prospectively identified in 2007-2008 and 2010-2013 from multiple health care providers, and enrolled into the population-based registry. Health care resource utilisation for each patient was collected through active surveillance of case notes and investigations including specialist visits, diagnostic tests, medications, medical hospitalisation, and surgery. RESULTS: Off 276 incident cases of IBD, 252 [91%] were recruited to the registry, and health care cost was calculated for 242 (146 Crohn's disease [CD] and 96 ulcerative colitis [UC] patients). The median cost in CD was higher at A$5905 per patient (interquartile range [IQR]: A$1571-$91,324) than in UC at A$4752 [IQR: A$1488-A$58,072]. In CD, outpatient resources made up 55% of all cost, with medications accounting for 32% of total cost [15% aminosalicylates, 15% biological therapy], followed by surgery [31%], and diagnostic testing [21%]. In UC, medications accounted for 39% of total cost [of which 37% was due to 5-aminosalicylates, and diagnostics 29%; outpatient cost contributed 71% to total cost. CONCLUSION: In the first year of diagnosis, outpatient resources account for the majority of cost in both CD and UC. Medications are the main cost driver in IBD.

Prospective population-based cohort of inflammatory bowel disease in the biologics era: Disease course and predictors of severity.

BACKGROUND AND AIM: We have previously found high incidence of inflammatory bowel disease (IBD) in Australia. A population-based registry was established to assess disease severity, frequency of complications, and prognostic factors. METHODS: Incident cases were prospectively identified over 4 years. Early disease severity was assessed according to need for hospitalization and resective surgery and medication use. RESULTS: We report on the early outcomes (median 18 months, range 12-60 months) for 252 patients comprising 146 with Crohn's disease (CD), 96 with ulcerative colitis (UC), and 10 IBD undifferentiated. Eighty-seven percent of CD patients had inflammatory disease at diagnosis, and this reduced to 73% at 5 years (n = 38). Immunomodulators were prescribed in 57% of CD patients and 19% with UC. A third of all CD patients were hospitalized, the majority (77%) in the first 12 months. Risk factors for hospitalization included penetrating, perianal, and ileocolonic disease (P < 0.05). Twenty-four percent of UC patients were hospitalized, most within the first 12 months. Intestinal resection rates were 13% at 1 year in CD and 26% at 5 years. Risk factors include penetrating and stricturing disease (P < 0.001) and ileal involvement (P < 0.05). Colectomy rates in UC were 2% and 13% at 1 and 5 years. High C-reactive protein (CRP) at diagnosis was associated with colectomy. CONCLUSIONS: A high rate of inflammatory disease, frequent immunomodulator use in CD, and a low rate of surgery in both CD and UC were identified. In CD, ileal involvement and complex disease behavior are associated with a more severe disease course, while in UC a high CRP predicted this outcome.

Environmental risk factors in inflammatory bowel disease: a population-based case-control study in Asia-Pacific.

OBJECTIVE: The rising incidence of inflammatory bowel disease in Asia supports the importance of environmental risk factors in disease aetiology. This prospective population-based case-control study in Asia-Pacific examined risk factors prior to patients developing IBD. DESIGN: 442 incident cases (186 Crohn's disease (CD); 256 UC; 374 Asians) diagnosed between 2011 and 2013 from eight countries in Asia and Australia and 940 controls (frequency-matched by sex, age and geographical location; 789 Asians) completed an environmental factor questionnaire at diagnosis. Unconditional logistic regression models were used to estimate adjusted ORs (aOR) and 95% CIs. RESULTS: In multivariate model, being breast fed >12 months (aOR 0.10; 95% CI 0.04 to 0.30), antibiotic use (aOR 0.19; 0.07 to 0.52), having dogs (aOR 0.54; 0.35 to 0.83), daily tea consumption (aOR 0.62; 0.43 to 0.91) and daily physical activity (aOR 0.58; 0.35 to 0.96) decreased the odds for CD in Asians. In UC, being breast fed >12 months (aOR 0.16; 0.08 to 0.31), antibiotic use (aOR 0.48; 0.27 to 0.87), daily tea (aOR 0.63; 0.46 to 0.86) or coffee consumption (aOR 0.51; 0.36 to 0.72), presence of hot water tap (aOR 0.65; 0.46 to 0.91) and flush toilet in childhood (aOR 0.71; 0.51 to 0.98) were protective for UC development whereas ex-smoking (aOR 2.02; 1.22 to 3.35) increased the risk of UC. CONCLUSIONS: This first population-based study of IBD risk factors in Asia-Pacific supports the importance of childhood immunological, hygiene and dietary factors in the development of IBD, suggesting that markers of altered intestinal microbiota may modulate risk of IBD later in life.

Incidence and phenotype of inflammatory bowel disease based on results from the Asia-pacific Crohn's and colitis epidemiology study.

BACKGROUND & AIMS: Inflammatory bowel diseases (IBD) are becoming more common in Asia, but epidemiologic data are lacking. The Asia-Pacific Crohn's and Colitis Epidemiology Study aimed to determine the incidence and phenotype of IBD in 8 countries across Asia and in Australia. METHODS: We performed a prospective, population-based study of IBD incidence in predefined catchment areas, collecting data for 1 year, starting on April 1, 2011. New cases were ascertained from multiple overlapping sources and entered into a Web-based database. Cases were confirmed using standard criteria. Local endoscopy, pathology, and pharmacy records were searched to ensure completeness of case capture. RESULTS: We identified 419 new cases of IBD (232 of ulcerative colitis [UC], 166 of Crohn's disease [CD], and 21 IBD-undetermined). The crude annual overall incidence values per 100,000 individuals were 1.37 for IBD in Asia (95% confidence interval: 1.25-1.51; 0.76 for UC, 0.54 for CD, and 0.07 for IBD-undetermined) and 23.67 in Australia (95% confidence interval: 18.46-29.85; 7.33 for UC, 14.00 for CD, and 2.33 for IBD-undetermined). China had the highest incidence of IBD in Asia (3.44 per 100,000 individuals). The ratios of UC to CD were 2.0 in Asia and 0.5 in Australia. Median time from symptom onset to diagnosis was 5.5 months (interquartile range, 1.4-15 months). Complicated CD (stricturing, penetrating, or perianal disease) was more common in Asia than Australia (52% vs 24%; P = .001), and a family history of IBD was less common in Asia (3% vs 17%; P < .001). CONCLUSIONS: We performed a large-scale population-based study and found that although the incidence of IBD varies throughout Asia, it is still lower than in the West. IBD can be as severe or more severe in Asia than in the West. The emergence of IBD in Asia will result in the need for specific health care resources, and offers a unique opportunity to study etiologic factors in developing nations.