Background The risk of infections, especially severe infections (SI), remains of particular interest in rheumatoid arthritis (RA), both defective immune response and therapeutic immunosuppression being responsible.
The RABBIT Risk Score (RRS), an instrument developed and validated for RA in the German Biologics Register RABBIT and replicated in other RA settings (British Register), allows the estimation of SI occurring during 12 months according to patient characteristics, based on data from similar risk profiles.
Objectives To evaluate the RSS reliability in a Romanian RA cohort under different biologics, considering the agreement between observed and expected rates of SI at 12 months.
Methods Longitudinal study on 272 consecutive RA with moderate-to-severe active disease, starting their biologic according to local guidelines, enrolled between 2008 and 2016 in a single academic center.
Along with disease activity and therapeutic response, baseline RRS (http://www.biologika-register.de/en/home/risk-score/)was applied for each case, based on multiple risk factors for infections including age, functional status, chronic lung and renal comorbidities, previous SI, number of treatment failures, current biologic (TNF or non-TNF inhibitors), mean corticosteroid dose.
The predictive value of RRS was considered by comparing the number and rate of expected versus reported SI in the first year of biologics (ROC curve, p<0.05), assessing the number of adverse events per year and per 100 patient-years, cases with at least one infection.
Statistical analysis (univariate, multivariate) was stratified according to different predictors of infection, patients being classified in two groups based on their recruitment before (2008–2012) and after (2013 up to date) implementation of national biologic register RRBR.
Results The performance of RSS was previously established in a pilot study on 181 RA. Currently, the RSS was considered in 144 RA recruited to the first group and 128 to the second. The prescription pattern significantly changed (p<0.05) for patients enrolled in last years: RA were more likely to receive earlier bDMARD, for lower activity and functional status; moreover, lower corticosteroids (dose, duration) and fewer synthetic DMARDs before starting biologics were reported (p<0.05).
24.63% RA developed SI (a total of 67 episodes, 1.47% fatal outcomes). Irrespective of RA settings and scenarios, history of biologics, specific drug administered (TNF or non-TNF), RRS indicated an outstanding agreement between the observed and expected SI rates (p>0.05).
In addition, the rate of SI was lower in RA recruited after 2013 (p<0.05), while RRS has better predictive significance in the second cohort (p<0.05).
Conclusions The RABBIT Risk Score is a consistent tool, able to predict serious infections in Romanian RA receiving biological therapy (TNF and non-TNF drugs), optimizing the selection of appropriate medication based of individual infectious risk profile in routine practice.
Disclosure of Interest None declared