Incidence and prevalence of inflammatory bowel diseases in gastroenterology primary care setting.

Background: The incidence of inflammatory bowel diseases (IBDs) has markedly increased over the last years, but no epidemiological study has been performed in gastroenterology primary care setting. We describe the epidemiology of IBD in a gastroenterology primary care unit using its records as the primary data source.

Methods: Case finding used predefined read codes to systematically search computer diagnostic and prescribing records from January 2009 to December 2012. A specialist diagnosis of Ulcerative colitis (UC), Crohn's disease (CD), inflammatory bowel disease unclassified (IBDU) or segmental colitis associated with diverticulosis (SCAD), based on clinical, histological or radiological findings, was a prerequisite for the inclusion in the study. Secondary, infective and apparent acute self-limiting colitis were excluded.

Results: We identified 176 patients with IBD in a population of 94,000 with a prevalence 187.2/100,000 (95% CI: 160.6-217.0). Between 2009 and 2012 there were 61 new cases. In particular, there were 23 new cases of UC, 19 new cases of CD, 15 new cases of SCAD, and 4 new cases of IBDU. The incidence of IBD was 16.2/100,000 (95% CI 12.5-20.7) per year. The incidence per year was 6/100,000 (95% CI 3.8 to 8.9) for UC, 5/100,000 (95% CI 3.0-7.7) for CD, 4/100,000 (95% CI 2.3-6.5) for SCAD, and 1/100,000 (95% CI 0.3-2.6) for IBDU.

Conclusions: We assessed for the first time which is the prevalence and incidence of IBD in a gastroenterology primary care unit. This confirms that specialist primary care unit is a key factor in providing early diagnosis of chronic diseases.