Infection and Malignancy Risk in Patients Treated with TNF Inhibitors for Immune-Mediated Inflammatory Diseases

Background: Infectious and malignant events are responsible for morbidity and mortality in patients with Immune-Mediated Inflammatory Diseases (IMIDs). Anti-tumor necrosis factor (Anti-TNF) agents appear to have an impact, however the individual effect of these agents in the different conditions is still unclear. Objective: The aim of this study is to estimate the Incidence Rates (IR) of infections and malignancies in patients treated with anti-TNFs across different IMIDs, as well as potential risk factors. Methods: IR/100 patient-years were evaluated in adult patients treated for any IMID with an anti-TNF between January 2000 and December 2014. Predictors were tested with bivariate and multivariate statistical analysis. Results: The IR/100 patient-years of serious infections was 4.02 (95% CI 3.20-5.04) with significant differences across IMIDs and anti-TNF agents. The most frequent site of serious infection was the gastrointestinal system. Five cases [IR of 0.28 (95% CI 0.12-0.66) /100 patient-years] of tuberculosis were diagnosed, exclusively in patients treated with monoclonal antibodies. Three (60%) of those were extrapulmonary. The IR/100 patient-years of malignancy was 1.75 (95% CI 1.24-2-47). Conclusion: There is significant variability in the IR of infections across indications and agents. Thus, physicians should be thoughtful when generalizing data from literature regarding the use of an anti-TNF agent in a specific IMID. Further studies are necessary to clear aspects regarding the safety of individual anti-TNF biologics and to clarify their impact in the different IMIDs.