Relationships between Chronic Cough and Asthma Control and Quality-of-Life in Patients with Severe Asthma: A 6-Month Longitudinal Analysis.

Background: The prevalence and clinical implications of chronic cough (CC) in patients with severe asthma receiving asthma treatment remain relatively unknown.

Objective: This study aimed to evaluate the relationships between CC and asthma control and quality-of-life (QoL) in patients with severe asthma through longitudinal analysis.

Methods: Baseline and 6-month follow-up data from the Korean Severe Asthma Registry were analyzed. CC was defined as a cough visual analog scale (VAS) score of ≥40 at both baseline and 6-months. Demographic parameters and clinical outcomes were compared between patients with severe asthma and CC and those without CC. Generalized estimating equation (GEE) analysis was performed to identify associations of CC with asthma control and QoL scores.

Results: Of the total 286 participants with severe asthma, 116 (40.6%) were defined as having CC. Patients with CC had higher baseline cough and wheeze severity VAS scores (all P<0.001), poorer asthma control (P<0.001), and worse QoL (Severe Asthma Questionnaire [SAQ] and Euro-QoL 5-dimension [EQ-5D] index, all P<0.001), compared to those without CC. During follow-up, patients with CC were more frequently exposed to oral corticosteroids (58.6% vs. 38.6%, P=0.010) and experienced more frequent asthma exacerbations (48.3% vs. 28.6%, P=0.009) than those without CC. GEE analysis revealed that CC was independently associated with poor asthma control, lower SAQ scores, and lower EQ-5D index after adjusting for confounders.

Conclusion: The presence of CC was associated with worse asthma control and QoL in patients with severe asthma. Further studies are warranted to better evaluate and manage CC in these patients.