Cognitive Impairment in Patients with Ankylosing Spondylitis

Background: Little is known about the potential systemic effects of ankylosing spondylitis (AS) on the nervous system. We designed a study aiming to assess the frequency and clinical predictors of cognitive impairment in AS patients. Methods: We carried out a cross-sectional case-control study composed of consecutive patients with AS. Trained and blinded interviewers registered clinical-epidemiological data and applied a standardized neurological assessment for each subject of the study. At baseline, functional limitations were characterized using the Health Assessment Questionnaire. Cognitive impairment was evaluated with the Brief Cognitive Screening Battery, the Montreal Cognitive Assessment, and the Clinical Dementia Rating, while neuropsychiatric symptoms were investigated with the Hospital Anxiety and Depression Scale. Healthy controls were matched for age, educational attainment, sex, and comorbidities. We compared the neurological outcomes between case and controls, and we determined the clinical predictors of cognitive decline. Results: We included 40 patients (mean: 49.3 years) with AS and 40 healthy controls (mean: 48.8 years) in our study. In Brief Cognitive Screening Battery, patients with AS presented a statistically significant poor performance in the clock drawing test and in the verbal fluency. The mean Montreal Cognitive Assessment (MoCA) scores were significantly lower in AS subjects compared to the control group. Also, the prevalence of subjects classified as cognitively impaired according to MoCA was significantly higher in the AS group (90.0% vs. 57.5%, p = 0.02). Moreover, neuropsychiatric symptoms were more prevalent in AS patients. Worse functional limitations were associated with poor cognitive performance as well. Conclusions: Patients with AS might be more vulnerable to cognitive decline.