Background The Tumour Necrosis Factor alpha antagonists therapy (anti-TNFa) and new molecules such as abatacept and rituximab, have dramatically changed the treatment of rheumatoid arthritis (RA). Previous research work has shown that the anti-TNFatherapy combined with traditional Disease Modifying AntiRheumatic Drugs (DMARDs) has increased the number of infections compared to placebo. The use of selected populations inhibited the extrapolation of the results to the global RA patients. Also, there are few clinical studies presenting safety results data comparing traditional DMARDs and Biological DMARDs (BioDMARDs) therapy.
Objectives The objective of the current study is to characterize and compare the relative risk of infection in patients undergoing therapeutic with traditional DMARDs and/or BioDMARDs, using data from the portuguese databases BioreportAR and RegistAR.
Methods The population considered for this study was extracted from the BioreportAR database, which registered all the patients undergoing BioDMARDs, and a sample from RegistAR database which registered patients undergoing solely traditional DMARD therapy, but limited to those followed in the Rheumatology Service of CHLO. A logistic regression model was applied, where the presence of infection was the independent variable. Pearson and Fisher tests were used to verify the association between categorical variables. The statistic analysis was performed using STATA 12.0.
Results The population was composed by 283 patients, which were split into two groups, one with 83 patients undergoing BioDMARD therapy and the other with 200 patients undergoing DMARDs therapy. Their average age was 62.5 years, and 80% were female with an average RA duration of 8.43 years. Of this population, 81% were undergoing a prednisone dose of 5 to 10mg/day, 94% were undergoing traditional DMARDs for an average of 5.3 years, and 23% were undergoing BioDMARDs for an average of 4.3 years. A total of 133 infections occurred in 28% of the patients (40% respiratory tract, 37% urinary tract, 14% skin), of which only 7% were considered serious, leading to hospitalization. Comorbilities were identified in 45% of the patients, where Diabetes Mellitus (DM) and smoke addiction were the most frequent. Both groups presented significant differences in age, RA disease duration, DMARD therapy duration, and number of infected patients. The analysis indicated that DMARD and DM increased the relative risk of infection, but without significant difference between both groups. The steroids therapy didn’t have direct effect on the relative risk of infection. The BioDMARD therapy increased the relative risk of infection by 49,7%, and exposure time to therapy also showed direct impact on the former variable.
Conclusions The analysis performed on the population sample extracted from the portuguese RA database, indicated that The BioDMARD therapy increased the relative risk of infection, and the direct role of DMARD in also increasing such risk. Surprisingly, the steroids therapy did not have any effect on infection risk, most likely due to the low dosage (prednisone <15mg/day). The heterogeneity of the population disables the possibility for any generalization or extrapolation of the results.
Disclosure of Interest None Declared