[Infections in Patients With Rheumatoid Arthritis Undergoing Anti-TNFα Drug Therapy].

Infections are more frequent in patients with rheumatoid arthritis (RA). The capacity of the anti-TNF drugs (infliximab, etanercept, and adalimumab) to increase the risk of infections has been a motive of discussion during the past years. Only in two of the trials that have allowed the marketing of the infliximab and adalimumab more serious infections were observed. TB was not observed in the trials. Nevertheless, later they have been published not controlled studies that show infections and TB in patients with RA that receive anti-TNFα drugs. The disagreement between the trials and the not controlled studies has been the motive of the accomplishment of metaanalysis which study the frequency of infections in patients with RA that receive anti-TNFα drugs. The three metaanalysis published show an increase of the risk of infections in patients with AR in treatment with infliximab and with adalimumab, specially when they administer high doses. This risk does not seem to increase with etanercept, probably due to the fact that doses superior to the recommended ones have not been used in the analyzed trials. Increased risk of infections was not detected in the trials, but the metaanalysis increases the statistical power and allow demonstrating increased risk of infections. A causal relation exists between the administration of anti-TNFα and the development of infections, fulfilling all the criteria of causality.