Risk factors for intestinal ischaemia among patients registered in a UK primary care database: a nested case-control study.

BACKGROUND: Intestinal ischaemia, including ischaemic colitis and acute mesenteric ischaemia, causes significant morbidity and mortality. Few population-based studies have estimated incidence and potential risk factors for this disease. AIMS: To estimate the incidence of intestinal ischaemia and identify the associated risk factors in cohorts: (i) patients with irritable bowel syndrome and/or chronic constipation (IBS/CC/both), (ii) individuals free of these conditions. METHODS: Population-based case-control analysis nested in a cohort of patients with first ever recorded diagnosis of IBS/CC/both and a cohort free of these conditions from general population using the General Practice Research Database. RESULTS: Of 78 cases of intestinal ischaemia, 71 were from general population, seven from the IBS/CC/both cohort. Incidence rate of intestinal ischaemia in IBS/CC/both patients vs. general population was 4.49:1.09 per 100,000 person-years; age- and gender-adjusted incidence rate ratio (95% CI) was 2.7 (1.2-5.9). Inflammatory bowel disease and heart failure showed an association with ischaemic colitis [OR (95% CI): 4.2 (0.5-38.4) and 5.6 (2.2-14.1)], but none with acute mesenteric ischaemia. Diabetes and prior cardiovascular surgery were associated with higher risk of acute mesenteric ischaemia, but showed no association with ischaemic colitis. CONCLUSIONS: Results suggest that different risk factors are associated with acute mesenteric ischaemia and ischaemic colitis. However, due to small number of patients, associations should be carefully interpreted.