OP0284 OUTCOME OF COVID-19 IN PATIENTS WITH RHEUMATIC AND INFLAMMATORY DISEASES TREATED WITH RITUXIMAB: DATA FROM DE FRENCH RMD COVID-19 COHORT
Authors: J. Avouac, E. Drumez, E. Hachulla, R. Seror, S. Georgin-Lavialle, S. El Mahou, E. Pertuiset, T. Pham, H. Marotte, A. Servettaz, F. Domont, P. Chazerain, M. Devaux, P. Claudepierre, V. Langlois, A. Mekinian, A. Maria, B. Banneville, B. Fautrel, J. Pouchot, T. Thomas, R. M. Flipo, C. Richez
Journal: Annals of the Rheumatic Diseases (2021)

Background: Various observations have suggested that the course of the COVID-19 infection may be less favorable in patients with inflammatory rheumatic and musculoskeletal diseases (iRMD) receiving rituximab (RTX). Objectives: To investigate whether treatment with RTX is associated with severe infection and death. Methods: We performed an observational, multicenter, French national cohort study querying the French RMD COVID-19 cohort, including highly suspected/confirmed iRMD-COVID-19 patients. The primary endpoint was to assess the severity rate of COVID-19. Severe disease was defined by hospitalization in intensive care unit or death. The secondary objectives were to analyze death rate and length of hospital stay. Two control groups were considered for comparison with RTX treated patients: a first group including all non-RTX treated iRMD patients and a second consisting on RTX untreated iRMD patients with diseases for which RTX is a recognized therapeutic option. Adjusting on potential confounding factors was performed by using inverse probability of treatment weighting (IPTW) propensity score method. Results: We collected a total of 1090 records. Patients were mainly females (67.3%, 734/1090) with a mean age of 55.2±16.4 years, and 51.1% (557/1090) were over the age of 55. Almost 70% of the population had at least one comorbidity (756/1090). A total of 63 patients were treated with RTX, mainly for rheumatoid arthritis (RA) (31/63, 49.2%). RTX treated patients were more likely to be males, with older age, higher prevalence of comorbidities and corticosteroid use. The control population consisted on 1027 non-RTX treated iRMD patients, and 495 RTX untreated iRMD patients with diseases for which RTX is a recognized therapeutic option. Of the 1,090 patients, 137 developed severe disease (12.6%). After adjusting on potential confounding factors (age, sex, arterial hypertension, diabetes, smoking status, body mass index, interstitial lung disease, cardiovascular diseases, cancer, corticosteroid use, chronic renal failure and the underlying disease), severe disease was confirmed to be observed more frequently in patients receiving RTX compared to all RTX untreated iRMD patients (effect size, ES 3.26, 95% confidence interval, CI 1.66 to 6.40, p&lt;0.001) and the subgroup of untreated RTX patients with diseases eligible for RTX therapy (ES 2.62, 95% CI 1.34 to 5.09, p=0.005). Patients who developed a severe disease had a more recent rituximab infusion compared to patients with mild or moderate disease. Indeed, the time between the last infusion of rituximab and the first symptoms of COVID-19 was significantly shorter in patients who developed a severe form of COVID-19 (Figure 1). Figure 1. Distribution (Tukey’s box plot) of Lag time between last infusion of Rituximab according to disease severity. P-Values for comparison between disease severity with Kruskal Wallis test are reported; P-Value&lt;0.001 for either post-hoc comparison of severe disease group with moderate or mild disease group (calculated using Dunn’s test). Eighty-nine patients in our cohort died, resulting in an overall death rate of 8.2%. Death rate was numerically higher in RTX treated patients (13/63, 20.6%) compared to all RTX untreated iRMDs patients (76/1027, 7.4%) and the subgroup of untreated RTX patients with diseases eligible for RTX therapy (49/495, 9.9%). After considering the previously described confounding factors, the risk of death was not significantly increased in patients treated with RTX compared to all RTX untreated iRMDs patients (ES 1.32, 95% CI 0.55 to 3.19, p=0.53) (Table 2) and the subgroup of untreated RTX patients with diseases eligible for RTX therapy (ES 1.48, 95% CI 0.68 to 3.20, p=0.32). In line with a more severe COVID-19 disease, the length of hospital stay was markedly longer in patients treated with RTX compared to both untreated RTX patient groups. Conclusion: RTX therapy is associated with a more severe COVID-19 infection. RTX will have to be applied with particular caution in patients with iRMDs. Acknowledgements: Muriel Herasse played a major role in collecting the missing data of the cohort. We thank Julien Labreuche (biostatistician, CHU-Lille) for the help in the statistical analysis. Disclosure of Interests: None declared