Prevalence and associated factors of cough syncope in patients with chronic cough: a multicentre prospective study.

BACKGROUND: Cough syncope is a clinically significant complication of coughing, yet its epidemiology in patients with chronic cough remains poorly characterised. This study aimed to estimate the prevalence, and identify associated factors for cough syncope among patients with chronic cough. METHODS: Data were analysed from the Korean Chronic Cough Registry, a multicentre prospective observational study. Adults with newly referred chronic cough were followed for 1 year. Cough syncope was defined based on patient self-report at enrolment and the 1-year follow-up visit. We compared clinical characteristics between patients with and without cough syncope and performed multivariable logistic regression to identify independent associated factors. RESULTS: Among 682 eligible participants, cough syncope was identified in 13 (1.9%, 95% CI 1.0-3.2%). Patients with cough syncope were predominantly male (69.2% versus 31.1%; p=0.014) and had a higher median body mass index (30.5 versus 23.8 kg·m-2; p=0.001) compared to those without. They also exhibited a higher rate of refractory chronic cough (RCC) (84.6% versus 46.2%; p=0.006) and reported greater cough severity and hypersensitivity at 1 year, despite more frequent use of neuromodulators and opiates. Multivariable analysis identified obesity (adjusted (a)OR 4.65, 95% CI 1.24-17.47), RCC (aOR 4.08, 95% CI 1.09-15.23) and male sex (aOR 3.66, 95% CI 1.06-12.68) as independently associated with cough syncope. CONCLUSION: Cough syncope affects ∼2% of patients with chronic cough and is associated with male sex, obesity and refractory chronic cough, defining a distinct high-risk phenotype that warrants targeted risk stratification and prevention.