An observational study of cognitive function in patients with irritable bowel syndrome and inflammatory bowel disease.

BACKGROUND: Irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) are associated with several risk factors for developing cognitive impairment. These include altered cytokine levels, concurrent mood disorders, and the presence of chronic pain. This observational study aimed to explore the cognitive profile of patients with these conditions. METHODS: Participants completed the Cardiff Cognitive Battery, a series of computerized neuropsychological performance tests that examine a range of cognitive function including psychomotor speed, memory, and intelligence. A progressive analysis of covariance model was used with demographic details, anxiety and depression scores entered as covariates. Fecal calprotectin levels were measured in IBD patients to determine disease activity. KEY RESULTS: In total 231 participants were recruited (150 IBD patients, 40 IBS patients, and 41 healthy controls). IBD patients had significantly lower scores on fluid (p = 0.01) and crystalline intelligence tests (p = 0.028) compared to healthy volunteers, however, this reflected differences in concurrent mood disorder and level of education. When these factors were added as covariates, there was no significant difference between the groups. Duration and activity of disease did not affect cognitive function in IBD patients. Severity of symptoms had no impact on cognition in patients with IBS. CONCLUSIONS & INFERENCES: The results of this observational study do not support the hypothesis that IBS or IBD have an intrinsic disease process that is associated with cognitive dysfunction. It is possible that concurrent mood disorders, in particular depression, may affect the cognitive performance of patients with IBD in specific tasks.

Symptoms of irritable bowel syndrome in patients with inflammatory bowel disease: examining the role of sub-clinical inflammation and the impact on clinical assessment of disease activity.

BACKGROUND: Symptoms compatible with irritable bowel syndrome (IBS) are frequently present in patients with inflammatory bowel disease (IBD); however, the cause of this phenomenon is unclear. AIM: To determine the different contributions of 'true IBS' and sub-clinical inflammation in producing IBS-type symptoms in IBD patients, and to ascertain the impact these symptoms have on the clinical assessment of IBD activity. METHODS: In this cross-sectional study, 169 IBD patients completed questionnaires to assess disease activity, presence of IBS-type symptoms, and levels of anxiety and depression. Stool samples were collected for analysis of faecal calprotectin (FC). RESULTS: IBS-type symptoms were significantly more common in female patients (OR = 4.64, 1.55-13.88) and were associated with higher levels of anxiety (OR = 1.11, 1.01-1.21). There was no statistical difference between the FC levels of patients in clinical remission with IBS-type symptoms compared with those without (median values = 111 µg/g vs. 45.5 µg/g respectively, P = 0.171). The prevalence of IBS-type symptoms in patients with a normal FC level was 31%. CONCLUSIONS: A substantial number of IBD patients with normal faecal calprotectin level experience IBS-type symptoms. These patients exhibit similar features to people diagnosed with IBS in the general community, suggesting that the conditions are not mutually exclusive and may coexist in a considerable number of IBD patients. A systematic diagnostic approach is required to assess IBD patients with IBS-type symptoms as sub-clinical inflammation may play a role in a proportion of cases.