Cough Severity Index: Validation in Brazilian Portuguese.

ABSTRACT

OBJECTIVE: To develop a validity profile for the cough severity index in the Brazilian Portuguese language (CSI-Br). METHODS: The study sample consisted of 100 participants divided into Chronic Cough Group (CG; 50 individuals with a mean age of 46.4; standard deviation [SD] 11.7) and Healthy Control Group (HCG; 50 individuals with a mean age of 33.0 [SD 12.3]). The data collection procedures were as follows (a) application of CSI-Br for all participants; (b) application of the Voice Handicap Index (VHI)-10 and the Newcastle Laryngeal Hypersensitivity Questionnaire (LHQ-Br) in the CG; (c) application of CSI-Br for test-retest reliability with an interim of between 2-14 days. The CSI-Br validation was composed of five stages construct validity, reliability, reproducibility, convergent validity, and discriminant validity. RESULTS: In construct validity, the instrument identified two factors and explained 67.6% of the total variance. The reliability had a value of a=0.914. Reproducibility showed an ICC value of 0.909. CSI-Br showed a negative correlation with VHI-10 and a positive correlation with LHQ-Br in convergent validity. In discriminant validity, all items and factors differentiated participants in the CG from those in the HCG. CONCLUSION: The ten-item CSI-Br with two factors is reliable and valid for analyzing the severity of chronic cough symptoms in Brazilian individuals.