Infections in patients with rheumatoid arthritis treated with biologic agents

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Arthritis Rheum. 2005 Nov;52(11):3403-12.

Infections in patients with rheumatoid arthritis treated with

biologic agents.

Listing J, Strangfeld A, Kary S, Rau R, von Hinueber U, Stoyanova-

Scholz M, Gromnica-Ihle E, Antoni C, Herzer P, Kekow J, Schneider M,

Zink A.

German Rheumatism Research Centre, Schumannstrasse 21/22, D-10117

Berlin, Germany. Listing@...

OBJECTIVE: To estimate the incidence rates of serious and nonserious

infections in patients with rheumatoid arthritis (RA) who start

treatment with a biologic agent, and to compare these rates with

those in patients with RA who receive conventional treatment.

METHODS: Patients enrolled in the German biologics register between

May 2001 and September 2003 were included. Treating rheumatologists

assessed adverse events and serious adverse events. All adverse

events and serious adverse events experienced within 12 months after

study entry were analyzed. Propensity score methods were applied to

estimate which part of a rate increase was likely to be attributable

to differences in patient characteristics. RESULTS: Data were

available for 512 patients receiving etanercept, 346 patients

receiving infliximab, 70 patients receiving anakinra, and 601 control

patients treated with disease-modifying antirheumatic drugs. The

total number of adverse events per 100 patient-years was 22.6 (95%

confidence interval [95% CI] 18.7-27.2) among patients receiving

etanercept, 28.3 (95% CI 23.1-34.7) among patients receiving

infliximab, and 6.8 (95% CI 5.0-9.4) among controls (P < 0.0001).

Significant differences in the rate of serious adverse events were

also observed. For patients receiving etanercept, those receiving

infliximab, and controls, the total numbers of serious adverse events

per 100 patient-years were 6.4 (95% CI 4.5-9.1), 6.2 (95% CI

4.0-9.5), and 2.3 (95% CI 1.3-3.9), respectively (P = 0.0016). After

adjusting for differences in the case patient mix, the relative risks

of serious adverse events were 2.2 (95% CI 0.9-5.4) for patients

receiving etanercept and 2.1 (95% CI 0.8-5.5) for patients receiving

infliximab, compared with controls. CONCLUSION: Patients treated with

biologic agents have a higher a priori risk of infection. However,

our data suggest that this risk is increased by treatment with tumor

necrosis factor inhibitors.

PMID: 16255017 [PubMed - in process]