Najmi, Natasha

Abstract Objective Rituximab causes B‐cell depletion and hypogammaglobulinemia, increasing risk for infections. This study aims to determine the incidence of chronic rhinosinusitis (CRS) in patients following rituximab therapy. Study Design Retrospective cohort study using chart review of patients prescribed rituximab between January 2019 and January 2025. Setting Multisite study across Mayo Clinic Enterprise locations in Arizona, Florida, Minnesota, and Wisconsin. Methods Patients with documented rituximab use were included; those with pre‐existing CRS were excluded. Demographic and clinical data—including timing and duration of rituximab therapy, CRS diagnosis, comorbidities (asthma, allergic rhinitis, GERD), and need for sinus surgery—were collected. Descriptive statistics summarized patient characteristics. Group comparisons were performed using t ‐tests, Mann‐Whitney U , and chi‐square tests. Analyses were conducted using SPSS v28. Results Among 17,851 patients prescribed rituximab (median age 64.0 years, M:F ratio 1.1:1), 1105 (6.2%) developed CRS, with an annual incidence of 1.03% (1032 cases per 100,000 person‐years). The median duration of rituximab therapy for those diagnosed with CRS was 5.9 months (IQR, 0.5‐42.6). Most CRS cases occurred after rituximab discontinuation (62.7%, n = 693) compared to during active treatment (37.3%, n = 412). The median delay between rituximab discontinuation and CRS diagnosis was 17.0 months (IQR, 4.3‐41.7). Conclusions This study demonstrates an annual incidence of 1.03% for CRS diagnoses following rituximab. While prior studies report varying CRS incidences in the general population (0.25%‐0.73%), our findings suggest increased risk among rituximab users. Most CRS diagnoses occurred after rituximab discontinuation, emphasizing the need for a comprehensive medication history review during CRS evaluation.

Background A substantial proportion of patients with chronic rhinosinusitis (CRS) remain partly controlled or uncontrolled despite endoscopic sinus surgery (ESS) and maximal medical therapy. For these difficult-to-treat cases, topical antibiotic irrigations have been proposed as an adjunctive therapy, particularly when delivered via large-volume, low-pressure systems that enhance sinus penetration post-ESS. Evidence on their efficacy and prescribing patterns in this population remains limited. Objective This study aims to evaluate the use and outcomes of topical antibiotic irrigations in patients with difficult-to-treat CRS. Methods A retrospective, multi-site cohort study was conducted across tertiary academic medical centers. Adult patients with persistent CRS symptoms despite bilateral full-house ESS and conventional postoperative medical management were included. Patients with cystic fibrosis or granulomatosis with polyangiitis were excluded. Demographic, clinical, and treatment data were collected. Primary outcomes were infection resolution at 8 weeks and changes in Sino-Nasal Outcome Test-22 (SNOT-22) scores. Results Sixty-seven patients met inclusion criteria. Mupirocin (41.8%), tobramycin (23.9%), and gentamicin (17.9%) were the most commonly prescribed agents. After 8 weeks, 62.7% of patients achieved infection clearance. Among 44 patients with SNOT-22 data, scores improved significantly from 34.8 ± 20.2 to 21.8 ± 14.7 ( P < .001). Improvement in SNOT-22 scores was more pronounced in patients who cleared the infection compared to those who did not. Conclusion Large-volume topical antibiotic irrigations were associated with high infection resolution rates and clinically meaningful SNOT-22 improvements in patients with difficult-to-treat CRS. These findings support their potential utility as an adjunctive therapy in select postsurgical patients and warrant further prospective investigation.