Prevalence of refractory and unexplained chronic cough in adults treated in cough centre

Background Refractory and unexplained chronic cough (RCC; UCC) pose significant clinical challenges, impairing patients’ quality of life; however, defining RCC precisely remains elusive. Hence, this study aimed to assess RCC and UCC prevalence among patients referred to our cough centre and to analyse RCC prevalence relative to its definition.

Methods This prospective cohort study included all patients who were diagnosed at a cough clinic between 2018–2022. The response to therapy was measured based on the reduction in cough severity (via the Visual Analogue Scale [VAS]) and improvement in cough-related quality of life (via the Leicester cough questionnaire [LCQ]). RCC was defined as persistent cough severity, with none or minimal improvement (ΔVAS<30 mm) after ≥2 treatment attempts and cough severity ≥40/100 mm (VAS).

Results Of 201 patients treated for chronic cough, only three (1.5%) were diagnosed with UCC. Among 166 patients monitored for therapy response, 71 (42.8%) experienced a cough severity reduction in VAS ≥30 mm, while 100 (60.2%) showed an improvement in LCQ ≥1.5 points.

Based on the basic RCC definition, 51 of 166 patients (30.7%) were diagnosed. If applying stricter criteria (persistent severe cough ≥40 mm [VAS], insufficient therapy response <30 mm reduction [VAS], and <1.5 point improvement [LCQ]), RCC would be diagnosed in 45 subjects (27.1%).

Conclusions RCC is common in patients referred to cough clinics. The prevalence of RCC differs slightly depending on the diagnostic criteria. Therefore, it is necessary to clarify the definition of RCC used in routine practice.