According to Korean insurance claims data, individuals with seropositive rheumatoid arthritis (RA) had an almost twofold increased chance of developing Parkinson’s disease (PD) during a median follow-up period of approximately 4 years. This retrospective cohort study was published in the journal JAMA Neurology.
Dr. Jihun Kang and colleagues observed that the diagnosis rate of Parkinson’s disease in patients with RA and autoantibodies commonly associated with the disease was 1.2%, compared to 0.6% in non-RA controls (adjusted hazard ratio [HR] 1.95). Among the 328,080 individuals investigated (803 controls and 290 with RA), a total of 1,093 people with PD were identified. The risk of PD was 1.74 times higher in participants with RA compared to controls. Patients with seropositive RA had a higher risk of developing PD (adjusted HR 1.95) than those with seronegative RA (adjusted HR 1.20). The seropositive RA group had a greater risk of developing PD compared to the seronegative RA group (adjusted HR 1.61). This study establishes a link between RA and an increased risk of PD, with RA seropositivity further elevating the risk of developing PD.
A study conducted in 2022, which utilized data from four population-based studies and one Mendelian randomized study, contradicts the findings of the current study regarding the risk of PD in patients with RA. The combined data from these studies revealed that individuals with RA had a significantly lower risk of PD compared to those without the disease (risk ratio [RR] = 0.74, P = 0.034). Factors such as gender, age, area, follow-up period, and study design did not appear to have a noticeable impact on the risk of PD. Additionally, the Mendelian randomization analysis demonstrated a strong negative association between RA and PD (genetic correlation: 0.10, P = 0.0033), indicating that an increased risk of RA was linked to a lower chance of developing PD.
These results suggest that physicians should promptly refer patients to a neurologist upon the onset of early motor symptoms of PD in the absence of synovitis, and they should also be aware of the heightened risk of PD in individuals with RA. However, further research is necessary to comprehensively understand the underlying molecular mechanisms that contribute to the relationship between these two disorders.
References
- Kang J, Eun Y, Jang W, Cho MH, Han K, Jung J, Kim Y, Kim GT, Shin DW, Kim H. Rheumatoid Arthritis and Risk of Parkinson Disease in Korea. JAMA Neurol. 2023 May 1. doi: 10.1001/jamaneurol.2023.0932. Epub ahead of print. PMID: 37126341.
- Li D, Hong X, Chen T. Association between rheumatoid arthritis and risk of Parkinson’s disease: a meta-analysis and systematic review. Frontiers in Neurology. 2022;13.