Tuberc Respir Dis.  2020 Jan;83(1):31-41. 10.4046/trd.2019.0018.

Clinical Characteristics of Chronic Cough in Korea

• An TJ
• Kim JW
• Choi EY
• Jang SH
• Lee HY
• Kang HS
• Koo HK
• Lee JM
• Kim SK
• Shin JW
• Park SY
• Rhee CK
• Moon JY
• Kim YH
• Lee H
• Kim YH
• Kim JH
• Lee SH
• Kim DK
• Yoo KH
• Kim DG
• Jung KS
• Kim HJ
• Yoon HK
• on behalf of the Cough Study Group of the Korean Academy of Tuberculosis and Respiratory Diseases

• KMID: 2466618
• DOI: http://doi.org/10.4046/trd.2019.0018

Abstract

BACKGROUND
Chronic cough is defined as a cough lasting more than 8 weeks and socio-economic burden of chronic cough is enormous. The characteristics of chronic cough in Korea are not well understood. The Korean Academy of Tuberculosis and Respiratory Diseases (KATRD) published guidelines on cough management in 2014. The current study evaluated the clinical characteristics of chronic cough in Korea and the efficacy of the KATRD guidelines.
METHODS
This was a multi-center, retrospective observational study conducted in Korea. The participants were over 18 years of age. They had coughs lasting more than 8 weeks. Subjects with current pulmonary diseases, smokers, ex-smokers with more than 10 pack-years or who quit within the past 1 year, pregnant women, and users of cough-inducing medications were excluded. Evaluation and management of cough followed the KATRD cough-management guidelines.
RESULTS
Participants with chronic cough in Korea showed age in the late forties and cough duration of more than 1 year. Upper airway cough syndrome was the most common cause of cough, followed by cough-variant asthma (CVA). Gastro-esophageal reflux diseases and eosinophilic bronchitis were less frequently observed. Following the KATRD cough-management guidelines, 91.2% of the subjects improved after 4 weeks of treatment. Responders were younger, had a longer duration of cough, and an initial impression of CVA. In univariate and multivariate analyses, an initial impression of CVA was the only factor related to better treatment response.
CONCLUSION
The causes of chronic cough in Korea differed from those reported in other countries. The current Korean guidelines proved efficient for treating Korean patients with chronic cough.

Keyword

Cough; Cohort Studies; Epidemiology; Guideline; Diagnosis; Disease Management

MeSH Terms

Asthma
Bronchitis
Cohort Studies
Cough*
Diagnosis
Disease Management
Eosinophils
Epidemiology
Female
Gastroesophageal Reflux
Humans
Korea*
Lung Diseases
Multivariate Analysis
Observational Study
Pregnant Women
Retrospective Studies
Tuberculosis

Figure

• 

  Figure 1 Flow diagram of study. Overall 633 patients were screened. Current smoker and ex-smoker (quit within the past 1 year or more than 10 pack-years) were excluded. Angiotensin-converting enzyme (ACE) inhibitor users were excluded. Participants who were not more than 8 weeks of cough or 18 years old were excluded also. Four patients were lost during follow up. Finally, 427 participants were included in this study.

• 

  Figure 2 Treatment outcomes according to medication. For the treatment of upper airway cough syndrome (UACS), the combination of an antihistamine with a nasal decongestant had a better response than that by treatment with an antihistamine alone (p=0.03). For the treatment of cough-variant asthma (CVA), there was no significant difference in treatment outcome between an inhaler alone, such as inhaled corticosteroid (ICS) or ICS/long-acting β-agonist (LABA), and the combination of an inhaler with leukotriene receptor antagonist (LTRA) or oral corticosteroid (OCS) or LTRA plus OCS. Cough improved in the overall eosinophilic bronchitis (EB) group. There was no significant difference in gastro-esophageal reflux disease (GERD) treatment according to the proton-pump inhibitor (PPI) dose. *Antihistamine vs. antihistamine plus nasal decongestant (p<0.05).

• 

  Figure 3 Consistency between the initial impression and final diagnosis of chronic cough. All etiologies showed a high consistency between the initial impression and final diagnosis of chronic cough. Of those with and those without an initial impression of upper airway cough syndrome (UACS), 83% and 21.6%, respectively, were ultimately diagnosed with UACS. The final diagnosis was the same (86.2%) between those with an initial impression of cough-variant asthma (CVA) and those with an initial impression of eosinophilic bronchitis (EB). In contrast, the final diagnosis was not gastro-esophageal reflux disease (GERD) in 23.2% of those with an initial impression of GERD.

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