Gun-Woo Kim, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Woo-Jung Song, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Yoon-Seok Chang, MD, PhD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea
Shoaib Faruqi
,
Centre for Cardiovascular and Metabolic Research, Hull York Medical School, Castle Hill Hospital, East Yorkshire, United Kingdom
Ju-Young Kim, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Mingyu Kang, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Chungbuk National University Hospital, Seoul, South Korea
Sujeong Kim, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, South Korea
Eun-Jung Jo, MD
,
Pusan National University Hospital, Busan, South Korea
Min-Hye Kim, MD
,
Internal Medicine, Ewha Womans University, School of Medicine, Seoul, South Korea
So-Hee Lee, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Sun-Sin Kim, MD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Seoung-Eun Lee, MD
,
Pusan National University Hospital, Busan, South Korea
Jana Plevkova
,
Department of Pathophysiology & Simulation Centre, Jessenius Faculty of Medicine, Comenius University, Martin, Slovakia
Heung Woo Park, MD, PhD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Sang-Heon Cho, MD, PhD
,
Division of Allergy and Clinical Immunology, Department of Internal Medicine, Seoul National University Hospital, Seoul, South Korea
Alyn Morice, MD
,
Centre for Cardiovascular and Metabolic Research, Respiratory Medicine, Hull York Medical School, University of Hull, East Yorkshire, United Kingdom
Background: Lately, the evidence shows a huge epidemiological burden of chronic cough in general populations. However, the definitions of chronic cough varied, and no definitions were validated for clinical relevance. We examined existing epidemiological definitions in detail and investigated the operational characteristics.
Methods: A systematic literature review was conducted for the epidemiological studies that reported the prevalence of chronic cough in general adult populations, which were published in the peer-reviewed journals during the years 1980 to 2013. The operational characteristics of the most common definition were examined by meta-analyses of the male-to-female ratio in chronic cough prevalence.
Results: The systematic review included 70 studies. The most common definition was cough ≥ 3 months (12-month prevalence) without specification of phlegm (n=50), which conflicts with the criteria in clinical guidelines of cough ≥ 8 weeks.
Meta-analyses were conducted for the male-to-female ratio of chronic cough among 28 studies that reported sex-specific prevalence using the most common definition; however, the pooled male-to-female odds ratio was 1.26 (95% confidence interval 0.92–1.73) with significant heterogeneity (I2=96%, P<0.001), which was in contrast to previous clinical observations of female predominance in cough clinics.
Conclusions: This study indicates two important issues in defining chronic cough in further epidemiological studies. A conflict between epidemiological and clinical definitions in duration criteria needs to be resolved. Another unexpected difference in the gender preponderance between the community and clinics warrants clinical validation of the existing definition.
