(A1110) Demographic and Clinical Risk Factors for CRS Development Following Rituximab Use

Introduction: While conditions such as ANCA-associated vasculitis are linked to both rituximab use and chronic rhinosinusitis (CRS), the impact of other demographic and clinical factors on CRS development in this setting remains poorly understood. This study examines demographic and clinical risk factors for CRS and the need for endoscopic sinus surgery (ESS) after rituximab therapy.

Methods: Data were retrospectively collected from all Mayo Clinic sites using the Mayo Data Explorer. Patients with a history of rituximab use and subsequent CRS diagnosis were included. Demographics, clinical characteristics, and indications for rituximab use were collected.

Results: Among 1,105 patients (mean age 60.7 years ±16.1, M:F ratio 1.1:1), the primary indications for rituximab were non-Hodgkin lymphoma (NHL, 46.2%), chronic lymphocytic leukemia (CLL, 14.9%), and rheumatoid arthritis (RA, 11.0%). The mean duration of therapy was 29.1 months (±42.7), with a mean delay of 30.5 months (±36.2) between rituximab discontinuation and CRS diagnosis. ESS was performed in 149 patients (13.5%), with an average delay of 40.2 months (±47.9) after rituximab discontinuation. ESS rates were 27.4% for ANCA-associated vasculitis, 20.9% for immune thrombocytopenia, 14.0% for RA, 13.9% for CLL, and 11.0% for NHL. Surgical patients had significantly longer rituximab courses than non-surgical patients (38.4 vs 27.7 months, p = 0.007).

Conclusions: CRS development and the need for ESS are influenced by the underlying indication for rituximab use and the duration of therapy. Longer courses of rituximab were significantly associated with the need for surgical intervention, highlighting the importance of monitoring patients with prolonged rituximab exposure to identify those at increased risk for CRS development and ESS.