Reliability and validity of a Korean version of the leicester cough questionnaire

Purpose: There are no specific tools for measurement of the severity of chronic cough in Korea. We developed a Korean version of the Leicester Cough Questionnaire (LCQ) and tested its scaling and clinical properties. Methods: The LCQ was adapted for Korean conditions following a forward- backward translation procedure. All patients referred to chronic cough clinics at 5 university hospitals between May 2011 and October 2013 completed 2 questionnaires, the LCQ and the Short-Form 36 (SF-36), upon presentation and completed the LCQ and the Global Rating of Change (GRC) upon follow-up visits after 2 or 4 weeks. Concurrent validation, internal consistency, repeatability, and responsiveness were determined. Results: For the concurrent validation, the correlation coefficients (n=202 patients) between the LCQ and SF-36 varied between 0.42 and 0.58. The internal consistency of the LCQ (n=207) was high for each of the domains with a Cronbach's alpha coefficient of 0.82-0.94. The repeatability of the LCQ in patients with no change in cough (n=23) was high, with intra-class correlation coefficients of 0.66-0.81. Patients who reported an improvement in cough (n=30) on follow-up visits demonstrated significant improvement in each of the domains of the LCQ. Conclusions: The Korean version of the LCQ is a valid and reliable questionnaire for measurement of the severity of cough in patients with chronic cough.