Patients with ankylosing spondylitis (AS) have a significantly higher prevalence of overall dementia and Alzheimer dementia compared with the general population, according to the results of a nationwide, population-based, retrospective, longitudinal cohort study published in PLoS One.

Data in the study were obtained from the Korean National Health Insurance System (K-NHIS). The investigators sought to evaluate the association between dementia and AS using an extensive dataset from the K-NHIS. A total of 14,193 participants were selected as the AS group and 70,965 individuals were chosen as the age- and gender-matched control group. Researchers assessed patient demographics, household incomes, and comorbidities, including diabetes, dyslipidemia, and hypertension.

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The prevalence of overall dementia and Alzheimer dementia in the AS group (1.37% and 0.99%, respectively) was significantly higher than in the control group (0.87% and 0.63%, respectively). The adjusted hazard ratio (aHR) for overall dementia (1.758; 95% CI, 1.496-2.065) and the aHR for Alzheimer dementia (1.782; 95% CI, 1.474-2.154) in the AS group also demonstrated statistical significance. In contrast, the prevalence of vascular dementia did not differ significantly between the AS group and the control group (aHR, 1.409; 95% CI, 0.89-2.23).

In subgroup analyses, the following risk factors for dementia were reported in the AS group: age >65 years, male gender, fair household income (>20% of the median household income), no hypertension, no diabetes, and urban residency.

A major limitation was that risk factor analysis for AS and dementia was incomplete because certain detailed clinical variables in the K-NHIS dataset were not evaluated, including smoking status, alcohol consumption, family history of psychiatric illness, and body mass index. Additionally, information on the status of AS-related inflammation was not available.

The investigators concluded that comprehensive patient evaluation could help prevent the occurrence of dementia among patients with AS.

Reference

Jang HD, Park JS, Kim DW, et al. Relationship between dementia and ankylosing spondylitis: a nationwide, population-based, retrospective longitudinal cohort study. PLoS One. 2019;14(1):e0210335.