Exploring the concept of disease control in chronic cough.

Background: Disease control in chronic diseases is an overarching concept that reflects the degree to which the goals of therapy are met. However, to date, there is no consensus on the definition of disease control in chronic cough. This study aimed to provide a conceptual exploration of patient-reported cough control in chronic cough. Methods: This research is comprised of two subanalyses. First, patients with chronic cough receiving care at referral clinics were evaluated. Correlation analyses were performed between patient-reported cough control (a 5-point Likert scale), cough-specific patient-reported outcomes (PROs) and generic health PRO scores. Second, a survey was conducted among patients with refractory chronic cough and physicians to identify factors pertinent to cough control. Results: The analysis of 341 patients (mean age: 55.5±15.1 years; female: 66.6%) revealed that cough control rating was moderately correlated with cough severity visual analogue scale and Leicester Cough Questionnaire scores, while demonstrating weaker correlations with cough-associated throat symptoms, cough-related complications or general health-related quality of life (QoL). In the survey of patients and physicians, both groups considered certain factors, such as cough frequency, severity and impact on QoL, to be relevant to the concept of cough control. However, patients rated "need for cough rescue drug" notably higher than physicians. Conclusion: Patient-reported cough control was associated with cough severity or impact on QoL; however, cough control may not be fully captured by conventional cough PRO measurement tools. Further studies are warranted to define the consensus and tools to measure disease control in chronic cough.