The global epidemiology of chronic cough in adults: a systematic review and meta-analysis

Cough is an essential defence mechanism [1]. However, chronic cough is a significant cause of morbidity, seriously impairing quality of life [2]. Previously, chronic cough was considered a consequence of various diseases, such as asthma/eosinophilic bronchitis, rhinitis and gastro-oesophageal acid reflux disease [3, 4]. Recent evidence, however, suggests that chronic cough is a clinical syndrome with distinct intrinsic pathophysiology characterised by neuronal hypersensitivity [5–7]. Here, we estimated the worldwide epidemiological burden of chronic cough irrespective of putative diagnosis in general adult populations using a comprehensive systematic literature review. Chronic cough has a high global epidemiological burden. A standard definition would facilitate further studies. We gratefully acknowledge the help of GlaxoSmithKline (UK) in providing data translation assistance. We also wish to acknowledge the statistical advice from Soyeon Ahn (Division of Statistics, Medical Research Collaborating Center, Seoul National University Bundang Hospital, Seongnam, Korea).