Treatment of rheumatoid arthritis (RA) with disease-modifying anti-rheumatic drugs (DMARDs), either synthetic (sDMARDs) or biologic agents (bDMARDs) has significantly improved disease outcome. However, the impact of therapy-related adverse events (AEs), mild, moderate or serious, on disease outcome is under debate. The purpose of the study was to test the hypothesis that AEs, including infections, are rather common in patients receiving bDMARDs than in those receiving sDMARDs.
Analysis of the medical records of patients followed in a single outpatient clinic was performed. In total, 1403 adults (295 men, 1108 women) were included in the analysis (969 treated with sDMARDs only, 434 with bDMARDs). All AEs and infections were recorded and their severity was graded according to international criteria. Incident rates were calculated and Kaplan-Meier plots as well as Cox proportional-hazards models were performed to examine the association of treatment groups with the risk of any AE.
The risk of any AE, irrespective of severity, was significantly higher in patients with bDMARDs with the adjusted hazard ratio being 1.98 (95% CI: 1.64 to 2.39). Patients in the biologic group treated initially with infliximab or adalimumab had a higher risk of AE compared to patients receiving etanercept or other biologic agents. Among patients treated with methotrexate, those receiving a dose below 10 mg had a higher risk of any AE when compared to those receiving higher doses.
The risk of any AE among RA patients treated with bDMARDs was significantly higher compared to those treated with sDMARDs.