A32-25 Small Airway Involvement in Rhinitis and Sinusitis: A Functional Assessment Using Impulse Oscillometry

Abstract Rationale Sinusitis and rhinitis are frequent upper airway syndromes encountered in daily clinical practice, with a reported U.S. prevalence of 10-30% for the latter. If untreated, they are a known risk factor for developing comorbidities, including pulmonary affections, which could lead to small airway disease (SAD). This study aimed to determine the prevalence of SAD in patients with rhinitis and sinusitis. Methods A descriptive, cross-sectional study was conducted on patients presenting with upper respiratory symptoms of recent onset, including cough, dyspnea, or chest tightness, between May 2024 and August 2025. PulmoScan Fot Oscillometry was used following ERS guidelines; R5-R20 0,07 kPa/(L/s) and Z-score 1.645 defined SAD; X5, AX, and Fres parameters were also analyzed. Descriptive analyses were performed using frequency and percentage, applying both parametric and nonparametric statistical methods. Differences in paired proportions were evaluated using McNemar’s test, and the chi-square test was applied for group comparisons. Data were analyzed using SPSS v30, and a p-value 0.05 was considered statistically significant. Results A total of 72 patients were enrolled in the study, of whom 67.12% (n = 49) were female. The mean age was 35,33 (SD 22,49) years, and the mean BMI was 24.71 kg/m² (SD 5,62). The overall mean R5-R20 was 0.76 (SD 1.56) kPa/(L/s), and X5 was -1.51 (SD 0.06). The prevalence of SAD, measured using the R5-R20 cut-off, was 51.39% (n = 37). Abnormal X5 values were found in 77,78% (n = 56), AX in 90,28% (n = 165) and Fres 56,94% (n = 41). When applying the R5-R20 Z-score, the prevalence of SAD was lower at 29,17% (n = 21), which was statistically significant (p 0,001). Accordingly, the proportion of abnormal AX values decreased to 45,83% (n = 33) and Fres to 11,11% (n = 8), both of which were relevant (p 0,001). The X5 values did not differ significantly when analyzed using Z-scores. Conclusion Abnormal oscillometric findings have been observed in patients with rhinitis or sinusitis presenting with lower airway symptoms, revealing a high prevalence of small airway dysfunction (SAD). Fixed cut-off values identified a greater number of SAD cases than the Z-score criteria, with statistically significant differences for R5-R20, AX, and Fres. These results highlight the importance of including oscillometry in lung function assessment in this patient population. This abstract is funded by: None