Central nervous system demyelination associated with biological agents used in the treatment of rheumatologic diseases: a retrospective cohort study.

Objective: To evaluate the annual incidence rate and clinical characteristics of central nervous system (CNS) demyelinating disease in patients who receive biologic agents for rheumatic diseases.

Methods: Patients who received biologic agents due to rheumatic diseases were identified in a retrospective manner and data of the patients who developed CNS demyelinating disease were recorded.

Results: 4838 out of 5926 patients who attended regular follow-up visits, were included in the study. CNS demyelinating disease was observed in 7 patients for 19.391 patient-years. 4 of 7 were diagnosed with multiple sclerosis (MS). 6 out of 7 were under anti-TNF therapy and mean duration was 13 months under causative drugs. While annual incidence rate of CNS demyelinating disease was 36.1/100000 (95% CI: 17-75), annual multiple sclerosis incidence rate in rheumatologic patients exposed to biologic agents was 19.6/100000 (95% confidence interval 7-52).

Conclusion: When compared with the data obtained in our cohort with annual incidence rates of multiple sclerosis in Europe, it is possible to conclude that there is an increase in the incidence of demyelinating events. Therefore, clinicians must be aware of neurological signs and symptoms in patients who receive biologic agents.