Characteristics of different asthma phenotypes associated with cough: a prospective, multicenter survey in China.

BACKGROUND: Asthma is a heterogeneous disease with variable symptoms, which presents with cough either as the sole or predominant symptom with or without wheezing. We compared the clinical and pathophysiological characteristics of cough predominant asthma (CPA), cough variant asthma (CVA) and classic asthma (CA) in order to determine any differential phenotypic traits. METHODS: In 20 clinics across China, a total of 2088 patients were finally recruited, including 327 CVA, 1041 CPA and 720 CA patients. We recorded cough and wheezing visual analogue scale, Leicester cough questionnaire (LCQ) and asthma control test scores. Fractional exhaled nitric oxide (FeNO), induced sputum cell counts, and capsaicin cough challenge were also measured and compared. RESULTS: CPA patients more frequently presented with cough as the initial symptom, and laryngeal symptoms (p < 0.001), had less symptoms related with rhinitis/sinusitis and gastroesophageal reflux (p < 0.05) than CA patients. Comorbidities including rhinitis and gastroesophageal reflux were similar, while the proportion of COPD and bronchiectasis was higher in CA patients. There were no differences in FeNO levels, sputum eosinophil and neutrophil counts, FEV1 (%pred) decreased from CVA to CPA to CA patients (p < 0.001). Cough sensitivity was higher in CVA and CPA compared to CA (p < 0.001), and was positively correlated with LCQ scores. CONCLUSIONS: CVA, CPA and CA can be distinguished by the presence of laryngeal symptoms, cough sensitivity and airflow obstruction. Asthma-associated chronic cough was not associated with airway inflammation or comorbidities in our cohort. Trial registration The Chinese Clinical Trial Registration Center, ChiCTR-POC-17011646, 13 June 2017.

Diagnostic utility of fractional exhaled nitric oxide in prolonged and chronic cough according to atopic status.

BACKGROUND: Cough-variant asthma (CVA) and cough-predominant asthma (CPA) are the major causes of persistent cough in Japan. The utility of fractional exhaled nitric oxide (FeNO) measurement in the differential diagnosis of persistent cough has been reported, but the influence of atopic status, which is associated with higher FeNO levels, on the diagnostic utility of FeNO has been unknown. METHODS: We retrospectively analyzed 105 non-smoking patients with prolonged and chronic cough that were not treated with corticosteroids and anti-leukotrienes. RESULTS: CPA was diagnosed in 37 patients, CVA in 40, and non-asthmatic cough (NAC) in 28. FeNO levels were significantly higher in the CPA [35.8 (7.0-317.9) ppb] and CVA [24.9 (3.1-156.0) ppb] groups than in the NAC group [18.2 (6.9-49.0) ppb] (p < 0.01 by Kruskal-Wallis test). The optimal cut-off for distinguishing asthmatic cough (AC; CPA and CVA) from NAC was 29.2 ppb [area under the curve (AUC) 0.74, p < 0.01]. Ninety-one percent of subjects with FeNO levels ≥29.2 ppb had AC. Meanwhile, 40% of AC patients had FeNO levels <29.2 ppb. Stratified cut-off levels were 31.1 ppb (AUC 0.83) in atopic subjects vs. 19.9 ppb (AUC 0.65) in non-atopic subjects (p = 0.03 for AUC). CONCLUSIONS: Although high FeNO levels suggested the existence of AC, lower FeNO levels had limited diagnostic significance. Atopic status affects the utility of FeNO levels in the differential diagnosis of prolonged and chronic cough.

Retrospective Analysis of the Starting Dose of Combined ICS/LABA for Cough-variant Asthma and Cough-predominant Asthma.

BACKGROUND/AIM: Although the usefulness of inhaled corticosteroids and long-acting ß2 agonists (ICS/LABA) in cough-variant asthma and cough-predominant asthma has been reported, there is no consensus on its starting dose. The aim of this study is to find the optimal dose of ICS/LABA for cough-variant asthma and cough-predominant asthma. PATIENTS AND METHODS: We analysed 112 patients who visited our clinic from January 2009 to December 2012 with the chief complaint of cough that had continued for more than 3 weeks. Cough-variant asthma (n=30) and cough-predominant asthma (n=7) were treated with ICS/LABA. RESULTS: There was no significant difference in cough duration time from starting ICS/LABA in cough-variant asthma and cough-predominant asthma between medium and high doses (14.3% versus 10.9%, respectively) (p=0.192). Moreover, there was no significant difference in cough duration time from starting ICS/LABA in cough-variant asthma between medium and high doses (13.2% versus 11.5%, respectively) (p=0.433). CONCLUSION: The medium starting dose of ICS/LABA is sufficient for treating cough-variant asthma.

Retrospective Study of the Effects of Post-nasal Drip Symptoms on Cough Duration.

BACKGROUND/AIM: The aim of this study was to elucidate the significance of allergic rhinitis and post-nasal drip symptoms in patients with cough-variant and cough-predominant asthma. PATIENTS AND METHODS: We conducted a retrospective analysis of 91 patients who had cough-variant or cough-predominant asthma and first visited the Nakajima Medical Clinic in Japan between June 2012 and July 2015. RESULTS: Post-nasal drip symptoms were reported in 58 (63.7%) patients. The patients with post-nasal drip symptoms (19.5±8.3 days) had a significantly longer time until cough disappearance than those without post-nasal drip symptoms (11.0±4.8 days) (p=0.000034). Multivariate analysis showed that post-nasal drip symptoms are independent prolonged factors of cough duration. CONCLUSION: Post-nasal drip symptoms may affect cough control in patients with cough-variant and cough-predominant asthma.