Small airway evolution of a Brazilian severe asthmatic cohort (BRASASP): 10 years follow up

Introduction: After an extensive clinical, functional and inflammatory evaluation of a cohort of patients with severe asthma, which began more than 10 years ago, we can move forward in understanding and investigating the evolution of variables related to the small airways over time. Methodology: Reassessment of a cohort of 61 patients with severe asthma with at least 10 years of treatment and systematic follow-up. Functional parameters related to the small airway were measured and compared through plethysmography, and correlated with impulse oscillometry measures. Evolution analysis of clinical control and inflammatory/functional profile of this cohort was sent to ATS 2020. Results: Variables from 50 patients who are still under regular follow-up were compared. The mean TLC remained the same (109%), while the previous mean RV (170%) was increasing to 188% predicted, without differences. However, the median of the predicted ratio RV / TLC increased statistically significant from 159% to 205%. (Figure) It was also observed a statistically significant correlation (R=0,38) between ratio RV/ TLC and current oscillometry measures (5-20 Hz). Conclusion: After 10 years of regular follow-up with appropriate treatment, we observed a greater obstruction in a small airway in patients in our cohort of severe asthmatics, with a positive correlation between RV/TLC measurements on plethysmography and on impulse oscillometry.