DMARDSs do not reduce the risk for Parkinson disease in rheumatoid arthritis patients

The findings of a nested case-control study published in the journal of Neurology have concluded that the use of disease-modifying antirheumatic drugs (DMARDs) does not confer any protection against Parkinson disease (PD) among individuals with rheumatoid arthritis (RA).

The nationwide case-control study included 315 PD patients and 1571 control subjects enrolled from the Finnish PD (FINPARK) cohort. The enrolled subjects had RA > 3 years prior to their initial PD diagnosis. The mean age of the subjects was 73.1 years, with an increased predominance of female study participants. The Finnish Care Register for Health Care and Special Reimbursement Register was adopted for the identification of RA. Each individual with PD and RA was matched with up to 7 control subjects based on the sex, age, region, and duration of RA. The DMARDs were categorized into 5 classes, and the conditional logistic regression was used to evaluate the association after adjusting for confounders.

The median duration of RA noted in patients with PD was 12.6 years, as opposed to 11.6 years among control individuals. The study did not find any association between DMARDs, namely sulfasalazine, methotrexate, gold preparations, immunosuppressants, or corticosteroid use, and risk for PD. Whereas, chloroquine/hydroxychloroquine demonstrated a reduced risk for PD (adjusted odds ratio 0.74; 95% CI, 0.56-0.97).

Certain previous epidemiological studies have suggested an association between RA and PD, and some researchers have hypothesized that the DMARDs may interfere with immune responses noted in PD patients. In contrast, the present study findings suggest that the use of DMARDs does not explain the reduced risk for PD noted in RA patients. Moreover, it is necessary to further investigate the possible association between chloroquine/hydroxychloroquine and the lower risk of PD.

References: Paakinaho A, Koponen M, Tiihonen M, Kauppi M, Hartikainen S, Tolppanen AM. Disease-Modifying Antirheumatic Drugs and Risk of Parkinson Disease: Nested Case-Control Study of People With Rheumatoid Arthritis [published online ahead of print, 2022 Jan 21]. Neurology. 2022;10.1212/WNL.0000000000013303.