Disease-Modifying Antirheumatic Drugs and Dementia Prevention: A Systematic Review of Observational Evidence in Rheumatoid Arthritis

Background: Many observational studies have examined the association of disease-modifying antirheumatic drugs (DMARDs) with dementia risk, but the evidence has been mixed, possibly due to methodological reasons. This systematic review (PROSPERO: CRD42023432122) aims to assess existing observational evidence and to suggest if repurposing DMARDs for dementia prevention merits further investigation.

Methods: Four electronic databases up to October 26, 2023, were searched. Cohort or case-control studies that examined dementia risk associated with DMARDs in people with rheumatoid arthritis were included. Risk of bias was evaluated using the Cochrane Collaboration's Risk of Bias in Nonrandomized Studies of Interventions (ROBINS-I) criteria. Findings were summarized by individual drug classes and by risk of bias.

Results: Of 12,180 unique records, 14 studies (4 case-control studies, 10 cohort studies) were included. According to the ROBINS-I criteria, there were 2 studies with low risk of bias, 1 study with moderate risk, and 11 studies with serious or critical risk. Among studies with low risk of bias, one study suggested that hydroxychloroquine versus methotrexate was associated with lower incident dementia, and the other study showed no associations of tumor necrosis factor (TNF) inhibitors, tocilizumab, and tofacitinib, compared to abatacept, with incident dementia.

Conclusion: Studies that adequately addressed important biases were limited. Studies with low risk of bias did not support repurposing TNF inhibitors, tocilizumab, abatacept or tofacitinib for dementia prevention, but hydroxychloroquine may be a potential candidate. Further studies that carefully mitigate important sources of biases are warranted, and long-term evidence will be preferred.