Role of rheumatoid arthritis flare in the risk of Alzheimer's disease and related dementias: a population-based cohort study.

OBJECTIVE

Several studies have reported an association between rheumatoid arthritis (RA) disease activity and the risk of Alzheimer's disease and related dementias (AD/ADRD). We examined the role of RA flares on the risk of AD/ADRD.

METHOD: This population-based study was conducted on an inception cohort of RA patients aged ≥ 50 years, who were residents of Minnesota, USA (1988-2014). RA-related flare/remission status was ascertained via medical record review. In definition 1, flares were considered to start on the day of documentation and resolve halfway to the next visit. In definition 2, 'acute flares' were defined as lasting for 6 weeks. Incident dementia was defined by the presence of two ICD-9/10 codes for AD/ADRD ≥ 30 days apart. Cox models were used to assess the association of RA flares with AD/ADRD.

RESULTS

We included 774 patients with RA. During a median follow-up of 7.8 years, 79 patients (10%) developed AD/ADRD. During a total of 12 437 medical visits, patients were flaring at 3407 visits (27.4%) and in remission at 2900 visits (23.3%). Using definition 1, we found no significant evidence of a higher risk of incident AD/ADRD when in RA flare versus remission [hazard ratio (HR) 1.11, 95% confidence interval (CI) 0.63-1.96]. Using definition 2, patients with RA flare had an estimated 1.8-fold increased risk of AD/ADRD (HR 1.82, 95% CI 0.82-4.06) versus remission, which was not statistically significant.

CONCLUSION

We found that RA flares are common. A detrimental effect of active flares on cognitive status cannot be excluded.