Incidence and prevalence of inflammatory bowel disease in Devon, UK

Abstract

Background and aims: We sought to define temporal changes in prevalence of inflammatory bowel disease (IBD) in East Devon, UK, in order to facilitate service planning over the next 5 years.

Methods: Multiple primary and secondary care databases were used to identify and verify cases. Point prevalence and incidence of IBD were reported in April 2017 and from 2008 to 2016, respectively. Future prevalence and healthcare activity requirements were estimated by linear regression.

Results: Prevalence of ulcerative colitis (UC), Crohn's disease (CD) and inflammatory bowel disease unclassified (IBDU) were 479.72, 265.94 and 35.34 per 100 000 persons, respectively. In 2016, the incidence rates of UC, CD and IBDU were 15.4, 10.7 and 1.4 per 100 000 persons per year, respectively. There were no significant changes in the incidence of CD (p=0.49, R=0.26) or UC (p=0.80, R=0.10). IBD prevalence has increased by 39.9% (95% CI 28.2 to 53.7) in the last 10 years without differences in the rate of change between UC and CD. Overall, 27% of patients were managed in primary care, a quarter of whom were eligible but not receiving endoscopic surveillance. Outpatient clinics, MRI and biologic use, but not helpline calls, admissions, or surgeries increased over and above the change in IBD prevalence.

Conclusions: We report one of the highest prevalence and incidence rates of IBD from Northern Europe. Overall, IBD incidence is static, but prevalence is increasing. We estimate that 1% of our population will live with IBD between 2025 and 2030.

Keywords: epidemiology; inflammatory bowel disease; primary care.

Figure 1

Flow diagram showing the total number of cases at each stage in the search, excluded cases, subsequent primary and secondary care management breakdown. Patients were considered to be managed in secondary care if they had an outpatient appointment with gastroenterology, IBD nurses or surgeons in the last 3 years, without being expressly discharged from clinic, or had ongoing endoscopy in the last 3 years. GP, general practice; IBD, inflammatory bowel disease; IBS, irritable bowel syndrome; OPA, outpatient appointment; RDE, Royal Devon and Exeter Foundation NHS Trust.

Figure 2

(A) Age/sex pyramid of IBD versus Devon and UK background populations. Units given are percentages of the population group. (B) Age/sex pyramid of IBD by phenotype. Units given are percentages of the IBD cohort as a whole. IBD, inflammatory bowel disease.

Figure 3

Incidence per 100 000 of background population against time for UC (green) and Crohn’s disease (red). Mean incidence of UC was 17.7 (95% CI 15.8 to 19.6) per 100 000 background population per year, and the mean incidence of Crohn’s disease was 10.1 (95% CI 7.2 to 12.9) per 100 000 background population per year. Incident cases were defined as patients who lived within our catchment at the date of diagnosis. IBD, inflammatory bowel disease; UC, ulcerative colitis.

Figure 4

Age at diagnosis of IBD by disease and sex represented as density plot. Mean age at diagnosis for Crohn’s disease was 31 years (95% CI 22.0 to 46.8) and for ulcerative colitis was 37.8 years (95% CI 27.0 to 52.5). IBD, inflammatory bowel disease.

Figure 5

Prevalence of IBD 2008–2025, using linear regression model of historic and predicted future prevalence of all IBD, ulcerative colitis and Crohn’s disease. Shaded ribbon intervals represent 95% CIs taking into account incident rate, migration into area, migration out of area and death rate, respectively. IBD, inflammatory bowel disease.