Relationship between dementia and ankylosing spondylitis: A nationwide, population-based, retrospective longitudinal cohort study

Abstract

Among a variety of comorbidities of ankylosing spondylitis (AS), the association between dementia and AS by using an extensive dataset from the Korean National Health Insurance System was evaluated in this study. We extracted 15,547 newly diagnosed AS subjects among the entire Korean population and excluded wash-out patients (n = 162) and patients that were inappropriate for cohort match (n = 1192). Finally, 14,193 subjects were chosen as the AS group, and through 1:5 age- and sex-stratified matching, 70,965 subjects were chosen as the control group. We evaluated patient demographics, household incomes, and comorbidities, including hypertension, diabetes, and dyslipidemia. The prevalence of overall dementia (1.37%) and Alzheimer’s dementia (AD) (0.99%) in the AS group was significantly higher than in the control group (0.87% and 0.63%), respectively. The adjusted hazard ratio of the AS group for overall dementia (1.758) and AD (1.782) showed statistical significance also. On the other hand, the prevalence of vascular dementia did not differ significantly between the two groups. Subgroup analyses revealed the following risk factors for dementia in the AS group: male gender, greater than 65 years in age, fair income (household income greater than 20% of the median), urban residency, no diabetes, and no hypertension. From the nationwide, population-based, retrospective, longitudinal cohort study, AS patients showed a significantly higher prevalence of overall dementia and Alzheimer’s dementia. Comprehensive patient assessment using our subgroup analysis could help to prevent dementia in patients suffering from AS.

Ankylosing spondylitis is associated with an increased risk of dementia: A systematic review and meta‐analysis

“…Two studies were conducted in Europe 16,17 and the other 2 were conducted in Asia. 18,19 All studies used administrative databases to identify AS and dementia. All of them were of good quality reflected by a Newcastle-Ottawa score of at least 7.…”

“…Second, there was a high statistical heterogeneity in this meta-analysis which could be due to dissimilarity of study methodology (cohort vs case-control studies) and background population from each study. Interestingly, patients with AS in the study by Jang et al 18 had a significantly higher prevalence of comorbidities such as hypertension, diabetes mellitus, dyslipidemia and depression, which are known to be risk factors of dementia and may play roles as confounders. 13,[40][41][42] Finally, the small number of included studies could limit the ability to interpret the funnel plot.…”

“…Jang et al 18 Chen et al 19 Diagnosis of dementia Presence of the codes for Alzheimer's disease (ICD-10 F00 or G30), vascular dementia (ICD-10 F01.0, F01. ation.…”

“…Moreover, patients with AS could have limited physical activity which is another risk factor of dementia 14,15 . However, specific data on the relationship between AS and dementia are still conflicting 16‐19 . This systematic review and meta‐analysis was conducted in order to identify all relevant studies and summarize the results to further characterize the relationship between these 2 conditions.…”

Cognitive Impairment in Patients with Ankylosing Spondylitis

“…The only previous similar evidence that refers to a recent nationwide cohort study found that the prevalence of dementia in the AS group was significantly higher than those of the control group. 24 Also, cerebral functional deficits in patients with AS have already been observed in fMRI. 11 There are several possible explanations for cognitive impairment in patients with AS.…”