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.
Camila Moura Menezes, Rodrigo Dornelas, Mara Behlau and 1 others
The Cough Severity Index (cutoff 4.5, sensitivity 84.9%, specificity 83.0%) is a good screening tool for chronic refractory cough; the Laryngeal Hypersensitivity Questionnaire (cutoff 5.8, sensitivity 70.0%, specificity 73.4%) is moderate and should not confirm hypersensitivity alone.
Both now have Brazilian cutoff points.
Key findings
1The CSI-Br total score discriminated between individuals with and without chronic refractory cough with an AUC of 0.894 (95% CI 0.827–0.960); at the suggested cutoff of 4.50, sensitivity was 84.9% and specificity 83.0%.
2The LHQ-Br total score discriminated between the two groups with an AUC of 0.753 (95% CI 0.666–0.841); at the suggested cutoff of 5.8, sensitivity was 70.0% and specificity 73.4%.
3The authors stress that the two instruments measure different constructs (cough severity and life impact versus laryngeal hypersensitivity sensations) and that their similar sensitivity/specificity values should not be read as equivalence.
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What it does not show
The reference standard was the patient's own self-report of chronic refractory cough, not an objective physiological or laryngeal measure, so the accuracy figures reflect agreement with a subjective criterion rather than a gold standard. The two groups were very uneven (110 vs. 47), which the authors acknowledge may reduce the precision of the specificity estimate. The sample was exclusively individuals with a CRC diagnosis, while the LHQ-Br is intended for a broader laryngeal hypersensitivity population; generalisability to other laryngeal conditions is untested. The Brazilian LHQ-Br has a different structure (12 items, one factor, score by averaging) from the original English version (14 items, three factors, score by summing factor averages), so the cutoff is not directly comparable to the international one. The study was conducted in a context where objective diagnostic technologies for cough frequency and intensity are not commercially available, which may limit how the findings transfer to settings where those tools exist.
Declared interests
Funded by CAPES/CNPq (grant 88887.843759/2023-00), a Brazilian government research funding body. No industry sponsorship or author conflicts of interest were declared.
The easy way to misread this
Do not use the LHQ-Br cutoff of 5.8 alone to confirm laryngeal hypersensitivity in a patient. The authors state explicitly that its performance is 'acceptable and complementary' and should not be used in isolation to confirm symptoms. In addition, the reference standard throughout the study was the patient's own self-report of chronic refractory cough rather than an objective laryngeal or physiological measure, so the accuracy figures reflect how well the questionnaires match a subjective criterion, not a gold-standard diagnosis.
Summarised by AI from the full paper, without a clinician reviewing it. Check it against the source before it changes what you do. Read it on PubMed →