ABSTRACT: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.

BACKGROUND Ankylosing spondylitis (AS) is a chronic, progressive and inflammatory disease that commonly affects the vertebrae and the sacroiliac joints, causing pain and loss of mobility. Extra-articular manifestations vary widely in terms of both frequency and severity. In addition, recent studies have suggested that neurological manifestations might be more frequent than expected in autoimmune rheumatological diseases. Little is known about the potential systemic effects of AS on the nervous system. MATERIALS AND METHODS A cross-sectional and case-control study was performed including consecutive AS patients seen in a rheumatology outpatient clinic of referral tertiary hospital. The control group included 33 healthy subjects. We registered clinical and demographic data including age, sex, level of education, time of disease, time of diagnosis, drugs in use, cardiovascular risk factors and other comorbidities. Functional capacity was assessed using the Health Assessment Questionnaire (HAQ). Neurological appraisal was made with standardised questionnaires: Brief Cognitive Screening Battery (BCSB), Montreal Cognitive Assessment (MoCA), Clinical Dementia Rating (CDR) and the Hospital Anxiety and Depression (HAD). Analysis of the data was performed using qui-square and t-tests and a multivariate analysis (SPSS 22.0). Significance level was set as <0.05. RESULTS We included 35 patients (17 were female) with a mean age of 53.1 (±13.9) years; among these patients, almost all were under biologic therapy. The mean age of AS diagnosis was 41.9 (±13.9) years. In both univariate and multivariate analysis, compared to the control group, patients with AS presented significant lower BCSB, MoCA and CDR scores (p<0.05). Surprisingly, adjusting for level of education, just 12 and 8 patients presented normal BCSB and MoCA scores (p<0.01), respectively. The most affected domains were attention, delayed recall and executive functions. Cognitive decline was associated with higher HAQ scores (functional outcome due to AS) (p<0.05) but not with prolonged time of disease. No correlation was found between sex, disease-modifying antirheumatic drugs, HLA-B27, C-reactive protein and levels and the neurological impairment. The mean HAD score was 12.4 (±8.7) and anxiety and depression were more prevalent in AS patients than in control group (p<0.01). CONCLUSION This is the first study that evaluates cognitive impairment and neuropsychiatric effects of AS. Clinicians must be aware that patients with AS may have neurological manifestations of the disease. Further studies are encouraged to clarify the bond between the brain and AS.