Validation of the Clinical COPD Questionnaire as a psychophysical outcome measure in adult laryngotracheal stenosis

Objectives: To validate the Clinical Chronic Obstructive Pulmonary Disease Questionnaire (CCQ), a patient-administered instrument developed for bronchopulmonary disease as a disease-specific psychophysical outcome measure for adult laryngotracheal stenosis. Design: Prospective observational study. Settings: Tertiary/National referral airway reconstruction centre. Participants: Thirty-three tracheostomy-free patients undergoing endoscopic laryngotracheoplasty. Main outcome measures: CCQ and the Medical Research Council (MRC) Dyspnoea scale, a previously validated but more limited scale, were administered to patients 2 weeks before surgery, preoperatively, and 2 weeks after endoscopic laryngotracheoplasty. Pulmonary function was assessed preoperatively. Internal consistency was assessed with Cronbach alpha statistics and test-retest reliability was determined using intraclass correlation. Correlations between CCQ and MRC scale, and pulmonary function were used to assess convergent and divergent validity respectively. Instrument responsiveness was assessed by correlating total and domain-specific CCQ scores with anatomical disease severity and post-treatment effect size. Results: There were 12 males and 21 females. Mean age was 44 +/- 15 years. Cronbach alpha coefficient and intraclass correlation coefficient were 0.88 and 0.95 respectively. Total and domain-specific CCQ scores significantly correlated with the MRC scores (P < 0.001) and significant correlations between CCQ and peak expiratory flow rate and FEV1 were identified (P < 0.03). There were statistically significant changes in total and domain-specific CCQ scores when different stenosis severities were compared. Clinical COPD Questionnaire scores also changed significantly and congruently following surgery (P < 0.05 in both cases). Discussion: Clinical COPD Questionnaire is a valid and sensitive instrument for assessing symptom severity and levels of function and well-being in adult patients with laryngotracheal stenosis and can be used as a patient-centred disease-specific outcome measure for this condition.