Sensitivity, specificity, and cutoff points of the Cough Severity Index (CSI-Br) and the Newcastle Laryngeal Hypersensitivity Questionnaire (LHQ-Br) in individuals with chronic refractory cough.

Abstract

Purpose: To establish cutoff points and evaluate the discriminative accuracy of the self-perception instruments Cough Severity Index (CSI-Br) and Newcastle Laryngeal Hypersensitivity Questionnaire (LHQ-Br) in identifying symptoms related to chronic refractory cough (CRC) in adults.

Methods: This is a cross-sectional, observational, quantitative study with a sample of 157 participants (111 females and 46 males), with a mean age of 44.92 years. They were divided into two groups based on the presence or absence of CRC: Group with CRC (CRC-G) with 110 participants (31 males and 79 females), with a mean age of 48.67 (SD: 16.04) years; The study included a healthy control group (CG) with 47 participants (15 males and 32 females), with a mean age of 36.34 (SD: 14.31) years. Data were collected in person at the outpatient clinics of the participating hospitals and online via Google Forms. Participants answered the CSI-Br and LHQ-Br. Analysis was performed using SPSS 29.0 software, employing ROC curves to determine cutoffs and performance metrics.

Results: For the LHQ-Br, the area under the curve (AUC) was 0.753, with a cutoff of 5.8, sensitivity of 70%, and specificity of 73.4%. The CSI-Br had an AUC of 0.894 in the total score, with a cutoff of 4.5, sensitivity of 84.9%, and specificity of 83%.

Conclusion: Based on the established cutoffs, both questionnaires proved to be sensitive and specific, with greater robustness for CSI-Br.