RESUMEN
BACKGROUND: The safety profile of biologic drugs might present substantial regional differences. Since 2009, the Brazilian Society of Rheumatology has maintained BIOBADABRASIL (Brazilian Registry for Biologic Drugs), a registry for monitoring of biologic therapies in rheumatic diseases. OBJECTIVES: The aim of this study was to verify the incidence rate (IR) of serious infections in rheumatoid arthritis (RA) and spondyloarthritis (SpA) patients on biologic drugs. METHODS: BIOBADABRASIL prospectively included patients with rheumatic diseases who started the first biologic drug or a synthetic disease-modifying antirheumatic drug as a parallel control group. This study focuses on serious infectious adverse events (SIAEs) in RA and SpA patients on biologic drugs compared with controls, from January 2009 to June 2015. Time of exposure was set from initiation of the drug to the date of last administration or censorship. Serious infectious adverse events IR was calculated per 1000 patient/years with 95% confidence interval (CI). RESULTS: A total of 1698 patients (RA, 1121; SpA, 577) were included, 7119 patient/years. Serious infectious adverse events were more common among patients on tumor necrosis factor inhibitors (TNFi's) than controls (adjusted IR ratio, 2.96 [95% CI, 2.01-4.36]; p < 0.001). Subsequent TNFi was associated with a higher SIAEs incidence when compared with first TNFI (adjusted IR ratio, 1.55 [95% CI, 1.15-2.08]; p = 0.004). Serious infectious adverse events were associated with age and corticosteroids intake. Serious infectious adverse events were more frequent in the respiratory tract in all subgroups. CONCLUSIONS: In BIOBADABRASIL, biologic drugs, especially the subsequent TNFi, were associated with a higher risk of serious infections compared with synthetic DMARDs. Corticosteroid intake and age represented risk factors for SIAEs. Constant monitoring is required to follow the safety profile of drugs in the clinical setting of rheumatic conditions in Brazil.