Cognitive impairment in adult inflammatory bowel disease: a systematic review and meta-analysis

Abstract Background People living with inflammatory bowel disease (IBD) are exposed to multiple risk factors for cognitive impairment and frequently report cognitive difficulties. However, the presence of cognitive impairment in IBD has not been systematically evaluated. Methods Following PRISMA guidelines, we performed a systematic multi-database search for cross-sectional- and longitudinal studies comparing adults with IBD versus healthy controls for domain-specific cognitive function, or scores on multi-domain cognitive screening tools. For any domain reported by 3 or more studies, we conducted random-effects meta-analysis to calculate the standardised mean difference (SMD) between groups; lower scores reflected poorer performance. Between-study heterogeneity was assessed using the I2 statistic and study quality assessed using an IBD-modified Newcastle-Ottawa scale. Results Of 8302 articles screened, 12 studies (n=687) were included in the qualitative synthesis and 11 in meta-analyses. All studies were cross-sectional. Studies generally excluded people with active IBD and older adults. Despite no significant differences on multi-domain screening tools such as the MMSE (-0.27 [95% confidence interval -0.68, 0.08], p=0.14), people with IBD showed significant deficits compared to healthy controls in attention (SMD -0.36 [-0.60, -0.12], p=0.003, I2=0%), executive function (SMD -0.45 [-0.77, -0.13, p=0.005, I2=42.5%), and specifically in working memory (SMD -0.58 [-0.85, -0.30], p Conclusions People with IBD show deficits in attention and executive function, particularly in working memory, suggesting that cognitive impairment is a potential extraintestinal manifestation of IBD.