Cough persisting ≥ 2 weeks at a respiratory specialist clinic: a 4-year retrospective analysis of 860 patients

Abstract

Appropriate diagnosis and treatment of chronic cough are important to improve quality of life and reduce healthcare-related costs; however, comprehensive data on the diagnosis and treatment of persistent cough in respiratory specialist clinics are limited. This study aimed to identify the clinical characteristics, diagnostic distribution, and treatment practices among patients with persistent cough managed at a respiratory specialist clinic. This retrospective observational study included 860 patients with cough lasting ≥ 2 weeks, treated at a respiratory specialist clinic from January 2021 to December 2024. Patient characteristics, cough duration, final diagnosis, lung function results, medication use, and coronavirus disease (COVID-19) history were all analyzed. Patients were categorized according to cough duration at the initial visit into the 2-week (256 patients), 3–7-week (367 patients), and ≥ 8-week (237 patients) groups. The diagnoses of the 860 enrolled patients (62.0% female patients, mean age 41.7 ± 14.5 years) were as follows: cough variant asthma (CVA), 466 patients (54.2%); bronchial asthma, 168 patients (19.5%); bronchitis/post-infectious chronic cough, 94 patients (10.9%); and atopic cough (AC), 41 patients (4.8%). Complex diagnoses were made in 44 patients (5.1%), with CVA-associated conditions identified in 505 patients (58.7%). In the 2-week group, CVA was identified in 120 patients (46.9%) and AC in 10 patients (3.9%), indicating that treatable airway diseases were already common after 2 weeks of cough. The rate of complex diagnoses increased significantly with longer cough duration. Refractory rates differed according to cough duration at the initial visit, ranging from 0% in the 2-week group to 11.1% in the ≥ 8-week group ( p < 0.001). The overall prevalence of refractory cough was 5.0%. Patients with COVID-19 history ( n = 76, 8.8%) showed no increase in treatment resistance (refractory rate, 1.8% vs. 5.3%, p = 0.343). Treatable airway diseases, particularly cough variant asthma, were already common among patients presenting to a respiratory specialist clinic with cough persisting for ≥ 2 weeks. A history of COVID-19 was not associated with refractory cough. These findings highlight the clinical value of evaluating treatable airway diseases in patients with persistent cough. Not applicable.