The McMaster Cough Severity Questionnaire (MCSQ): a cough severity instrument for patients with refractory chronic cough

Elena Kum; Gordon H Guyatt; Rayid Abdulqawi; Peter Dicpinigaitis; Lieven Dupont; Stephen K Field; Cynthia L French; Peter G Gibson; Richard S Irwin; Faye Johnston; Lorcan McGarvey; Robert Newman; Nada Popovic; Jaclyn A Smith; Woo-Jung Song; Paul M O'Byrne; Imran Satia

doi:10.1183/13993003.01565-2024

The McMaster Cough Severity Questionnaire (MCSQ): a cough severity instrument for patients with refractory chronic cough

Eur Respir J. 2024 Oct 3:2401565. doi: 10.1183/13993003.01565-2024. Online ahead of print.

Authors

Elena Kum^{1

2}, Gordon H Guyatt^{1

2}, Rayid Abdulqawi³, Peter Dicpinigaitis⁴, Lieven Dupont⁵, Stephen K Field⁶, Cynthia L French⁷, Peter G Gibson⁸, Richard S Irwin⁷, Faye Johnston⁹, Lorcan McGarvey¹⁰, Robert Newman⁹, Nada Popovic⁹, Jaclyn A Smith¹¹, Woo-Jung Song¹², Paul M O'Byrne^{2

13}, Imran Satia^{14

13}

Affiliations

¹ Department of Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada.
² Department of Medicine, McMaster University, Hamilton, Ontario, Canada.
³ King Faisal Specialist Hospital and Research Centre and College of Medicine, Alfaisal University, Riyadh, Saudi Arabia.
⁴ Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, NY, USA.
⁵ Department of Respiratory Diseases, University Hospital Leuven, Katholieke Universiteit Leuven, Leuven, Belgium.
⁶ Department of Medicine, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada.
⁷ Division of Pulmonary, Allergy, and Critical Care Medicine, Department of Medicine, UMass Memorial Medical Center, Worcester, MA, USA.
⁸ Priority Research Centre for Asthma and Respiratory Diseases and Hunter Medical Research Institute, Faculty of Health and Medicine, The University of Newcastle, Callaghan, NSW, Australia.
⁹ Chronic Cough Canada, Canada.
¹⁰ Centre for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, Belfast, UK.
¹¹ Division of Infection, Immunity and Respiratory Medicine, University of Manchester, Manchester, UK.
¹² Department of Allergy and Clinical Immunology, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Korea.
¹³ Firestone Institute for Respiratory Health, St. Joseph's Healthcare, Hamilton, Ontario, Canada.
¹⁴ Department of Medicine, McMaster University, Hamilton, Ontario, Canada [email protected].

PMID: 39362666
DOI: 10.1183/13993003.01565-2024

Abstract

Background: Cough severity represents an important endpoint to assess the impact of therapies for patients with refractory chronic cough (RCC).

Objective: To develop a new patient-reported outcome measure addressing cough severity in patients with RCC.

Methods: Phase 1 (item generation): A systematic survey, focus groups, and expert consultation generated 51 items. Phase 2 (item reduction): From a list of 51 items, 100 patients identified those they had experienced in the previous year and rated their importance on a 5-point scale. The MCSQ included items reported to occur most frequently and that had the highest importance scores. Patient feedback on the MCSQ led to elimination of redundant items. Another 100 patients completed the MCSQ, from which we performed an exploratory factor analysis and a Rasch analysis to further refine items on the MCSQ.

Results: Phase 2 led to selection of 15 items from the initial 51. Patient feedback on the 15 items led to elimination of 5 redundant items. An exploratory factor analysis of the 10-item MCSQ led to selection of two domains, elimination of one item that demonstrated cross-loading, and another that had high inter-item correlations. A Rasch analysis of the 8-item MCSQ confirmed that the response options functioned in a logically progressive manner and that no items exhibited differential item functioning. The final 8-item MCSQ has a one-week recall period and includes two domains (intensity and frequency). The 8-item MCSQ had high internal consistency (Cronbach's alpha, 0.89), proved able to distinguish different levels of cough severity (Pearson separation index, 0.89), and demonstrated high cross-sectional convergent validity (Pearson's correlation, 0.76 [95% CI 0.66 to 0.83]) with the 100-mm cough severity visual analogue scale.

Conclusion: Initial evidence supports the validity of the MCSQ, an 8-item instrument measuring cough severity in patients with RCC. Future studies should evaluate its properties in measuring change over time.