Abstract 6 — Are Disease-Modifying Antirheumatic Drugs: for Rheumatoid Arthritis Associated with a Lower Risk of Dementia? A Systematic Review with Meta-Analysis

Background Dysregulation of several inflammatory cytokines including tumor necrosis factor (TNF) in dementia patients has also been identified as a key factor in the pathogenesis of rheumatoid arthritis (RA). We aimed to investigate the association of disease-modifying anti-rheumatic drugs (DMARDs) therapy for RA with risk of incident dementia. Methods Electronic database searches of PubMed, EMBASE and Cochrane Library were performed. Observational studies that assessed the association of dementia with DMARDs in RA were included. Pooled risk ratios (RRs) with 95% confidence intervals (CIs) were used as summary statistic. The certainty of evidence using the GRADE system. Results Fourteen studies involving 940,442 patients with RA were included. Pooled RR for developing dementia was 0.76 (95%CI 0.72-0.80) in patients taking biological DMARDs overall versus those taking conventional synthetic DMARDs, with 24% for TNF inhibitors (RR 0.76, 95%CI 0.71-0.82), 24% for non-TNF biologics (RR 0.76, 95%CI 0.70-0.83), separately. There was a significant subgroup effect among different types of TNF inhibitors (RR 0.58, 0.65, 0.80 for etanercept, adalimumab, infliximab, respectively; P-value between groups=0.002). However, compared with nonusers of DMARDs or investigative treatment, no significant effect on dementia incidence was observed in those receiving conventional synthetic DMARDs overall (RR 0.84, 95%CI 0.59-1.20), methotrexate (RR 0.78, 95%CI 0.54-1.12), hydroxychloroquine (RR 0.95, 95%CI 0.63-1.44), except for sulfasalazine (RR 1.27, 95%CI 1.06-1.50). Conclusions Biological DMARDs for RA are associated with decreased dementia risk, while protective effect is not observed in conventional synthetic DMARDs. Controlled clinical trials on TNF inhibitors is necessary to test their neuroprotective potentials.