Cognitive impairment in Crohn’s disease is associated with systemic inflammation, symptom burden and sleep disturbance

Abstract

Background: Patients with Crohn’s disease (CD) frequently complain of cognitive difficulties such as problems with concentration and clouding of thought, yet this has scarcely been objectively defined and underlying mechanisms remain unknown. Objective: The objective of this article is to objectively measure cognitive impairments in patients with CD compared with healthy controls, and if present, to identify potentially modifiable, contributing factors associated with cognitive impairment. Methods: CD patients and healthy age-/sex-matched controls completed surveys encompassing clinical, demographic, psychiatric, fatigue and sleep parameters. Contemporaneously, disease activity assessment with serum CRP, faecal calprotectin, Harvey–Bradshaw Index and the Subtle Cognitive Impairment test (SCIT) were performed, with the primary measure of response time (SCIT-RT) compared between groups. Multiple linear regression assessed for factors associated with slower SCIT-RT, denoting subtle cognitive impairment. Results: A total of 49 CD and 31 control individuals participated, with median age 44 years (range 22–65) and 43 years (21–63), respectively. Compared to controls, SCIT-RT was slower across all timepoints in CD patients (ANOVA p < 0.001). In multivariate analysis, serum CRP (standardised beta coefficient 0.27, 95% CI (0.02, 0.51)), abdominal pain (0.43 (0.16, 0.70)), plasma haemoglobin (1.55 (1.42, 1.68)), and concurrent fatigue (0.56 (0.25, 0.88)) were each independently associated with slower SCIT-RT in CD (each p < 0.05), with a trend for poorer sleep quality 0.54 (−0.03, 1.11) (p = 0.06), yet conversely, higher faecal calprotectin titres were associated with faster SCIT-RT (−1.77 (−1.79, −1.76), p < 0.01). Conclusions: Patients with CD demonstrated subtle cognitive impairment utilising the objective SCIT, correlating with systemic inflammation and other disease burden measures, although higher faecal calprotectin titres were unexpectedly associated with less cognitive impairment.