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Real-World Evidence of Severe Asthma Outcome Using 15-Year-Follow-Up Database

      Rationale

      Severe asthma is a chronic refractory airway disease, but the real-world characteristics and unmet needs of severe asthmatics are barely understood.

      Methods

      An integrated database was established, including 2,037 asthmatics (649 severe and 1,388 nonsevere asthmatics) who had been regularly monitored for 15 years. Demographic and clinical characteristics, lung function trajectories, exacerbation rates, and patterns of the medications of severe and nonsevere asthmatics were analyzed.

      Results

      Severe asthmatics had older age (41.8 ± 14.0 years vs. 35.1 ± 17.8 years, P < 0.001) and a higher female proportion (63.1% vs. 56.3%, P = 0.006). Baseline FEV1(%) and FEV1/FVC ratio were significantly lower in severe asthmatics (85.4 ± 19.6% vs. 94.2 ± 18.6%, FEV1; 80.8 ± 10.4 vs. 85.0 ± 9.2, FEV1/FVC; both P < 0.001). Severe asthmatics had more exacerbations (1.41-3.21 times per year) and higher medication requirements, including systemic steroids (72.4% vs. 41.8%, P < 0.001). The trajectory analysis for 15 years demonstrated a progressive decline of FEV1(%), persistent blood/sputum eosinophilia, and higher sputum neutrophil counts in severe asthmatics, while no decline of FEV1(%) and lower blood neutrophil counts were observed in nonsevere asthmatics (4,756.7 ± 2,568.5/μL vs. 4,198.4 ± 1,961.8/μL, P < 0.001, blood neutrophil count).

      Conclusions

      This is the first real-world evidence of severe asthma outcome, demonstrating the driving role of persistent eosinophilia and progressive lung function decline despite regular anti-inflammatory medications. The role of neutrophilia and further unmet needs have to be pursued for better outcome of severe asthma.