Abstract
Background: The Leicester Cough Questionnaire (LCQ) is a valid, reproducible, responsive self-reported cough-specific health status measure. It has been used to assess overall efficacy of treatments for cough, but its threshold for clinical significance, or patient importance, is unknown. The aim of this study was to determine the minimal important difference (MID) of the LCQ for patients with chronic cough; this is the smallest change in quality-of-life score considered to be clinically meaningful.
Methods: The LCQ MID was first estimated by a multidisciplinary panel of experts who reviewed two cases of chronic cough. It was subsequently determined using a standardized method. Fifty-two patients with chronic cough of more than 8 weeks' duration attending a respiratory outpatient clinic were recruited. Participants completed the LCQ at initial evaluation and repeated the LCQ with four Global Rating of Change Questionnaires (GRCQ) more than 2 months later. The LCQ total score ranges from 3 to 21 and from 1 to 7 for physical, psychological and social domains; a higher score indicates a better health-related quality of life. The GRCQ, a 15-point scale scored between +7 (a great deal better) and −7 (a great deal worse), was used to record patient ratings of change in cough symptoms. The MID was defined as the change in LCQ health status corresponding to a small change in the GRCQ score.
Results: The mean (standard deviation) LCQ MID corresponding to a small change in the GRCQ score was 1.3 (3.2); the MIDs for domains were as follows: physical 0.2 (0.8), social 0.2 (1.1) and psychological 0.8 (1.5). This MID for LCQ total score was similar to that determined by the expert panel. The global rating of change scores correlated significantly with the change in LCQ total and domain scores (r = 0.4−0.5; p < 0.005).
Conclusion: We have demonstrated that the LCQ MID is 1.3. The LCQ MID should aid clinicians and researchers to make meaningful interpretations of healthrelated quality-of-life data relating to chronic cough.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsPreview
Unable to display preview. Download preview PDF.
References
Beaton DE, Boers M, Wells GA (2002) Many faces of the minimal clinically important difference (MCID): A literature review and directions for future research. Curr Opin Rheumatol 14: 109–114
Birring SS, Prudon B, Carr AJ et al (2003) Development of a symptom specific health status measure for patients with chronic cough: Leicester cough questionnaire (LCQ). Thorax 58:339–343
Brightling CE, Ward R, Goh VV et al (1999) Eosinophilic bronchitis is an important cause of cough. Am J Respir Crit Care 160:406–410
Decalmer S, Webster D, Kelsall A, McGuinness K, Woodcock A, Smith A (2007) Chronic cough: How do cough reflex sensitivity and subjective assessments correlate with objective cough counts during ambulatory monitoring? Thorax 62:329–334
French CT, Irwin RS, Fletcher KE et al (2002) Evaluation of a cough-specific quality-of-life questionnaire. Chest 121:1123–1131
Guyatt GH, Berman LB, Townsend M et al (1987) A measure of quality of life for clinical trials in chronic lung disease. Thorax 42:773–778
Guyatt GH, Nogradi S, Halcrow VV et al (1989) Development and testing of a new measure of health status for clinical trials in heart failure. J Gen Intern Med 4:101–107
Guyatt GH, Norman GR, Juniper EF, Griffith LE (2002a) A critical look at transition ratings. J Clin Epidem 55:900–908
Guyatt GH, Osoba D, Wu AW, Wyrwich KW, Norman GR (2002b) Methods to explain the clinical significance of health status measures. Mayo Clin Proc 77:371–383
Jaeschkle R, Singer J, Guyatt GH (1989) Measurements of health status: Ascertaining the minimally clinically important difference. Control Clin Trials 10:407–415
Jones PW (2002) Interpreting thresholds for a clinically significant change in health status in asthma and COPD. Eur Respir J 19:398–404
Jones PW, Quirk FH, Baveystock CM (1991) The St George's Respiratory Questionnaire. Respir Med 85:25–31
Juniper EF, Guyatt GH, Willan A et al (1994) Determining a minimal important change in a disease-specific quality of life questionnaire. J Clin Epidemiol 47:81–87
McGarvey LPA, Heaney LG, MacMahon J (1998) A retrospective survey of diagnosis and management of patients presenting with chronic cough to a general chest clinic. Int J Clin Pract 52:158–161
Morice AH, Menon MS, Mulrennan SA et al (2007) Opiate therapy in chronic cough. Am J Respir Crit Care Med 175:312–315
Redelmeier DA, Guyatt GH, Goldstein RS (1996) Assessing the minimal important difference in symptoms: A comparison of two different techniques. J Clin Epidemiol 49:1215–1219
Wyrwich KW, Tierry WM (2002) Using the standard error of measurement to identify important changes in the asthma quality of life questionnaire. Qual Life Res 11:1–7
Wyrwich KW, Nienaber NA, Tierney WM, Wolinsky FP (1999) Linking clinical relevance and statistical significance in evaluating intra-individual changes in health-related quality of life. Med Care 37:469–478
Author information
Authors and Affiliations
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2009 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Raj, A.A., Pavord, D.I., Birring, S.S. (2009). Clinical Cough IV:What is the Minimal Important Difference for the Leicester Cough Questionnaire?. In: Chung, K.F., Widdicombe, J. (eds) Pharmacology and Therapeutics of Cough. Handbook of Experimental Pharmacology, vol 187. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-540-79842-2_16
Download citation
DOI: https://doi.org/10.1007/978-3-540-79842-2_16
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-79841-5
Online ISBN: 978-3-540-79842-2
eBook Packages: Biomedical and Life SciencesBiomedical and Life Sciences (R0)