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ORIGINAL ARTICLE

Clinical COPD Questionnaire in patients with chronic respiratory disease JANE L. CANAVAN,1 DENIZ DILAVER,2 AMY L. CLARK,2 SARAH E. JONES,1 CLAIRE M. NOLAN,1,2 SAMANTHA S. C. KON1 AND WILLIAM D.-C. MAN1 1

NIHR Respiratory Biomedical Research Unit, Royal Brompton & Harefield NHS Foundation Trust and Imperial College, and 2 Harefield Pulmonary Rehabilitation Unit, Royal Brompton & Harefield NHS Foundation Trust, Middlesex, UK

ABSTRACT Background and objective: The Clinical Chronic Obstructive Pulmonary Disease (COPD) Questionnaire (CCQ) is an easy to complete, health-related quality of life questionnaire which has been well-validated in COPD. The responsiveness of the CCQ in chronic respiratory disease patients other than COPD has not been previously described. The study aims were to determine if the CCQ in chronic respiratory disease correlates with other health related quality of life questionnaires, to assess the responsiveness of the CCQ to pulmonary rehabilitation and to determine the minimum important difference. Methods: The CCQ, COPD Assessment Test (CAT), the Chronic Respiratory Questionnaire (CRQ) and St George’s Respiratory Questionnaire (SGRQ) were measured in 138 chronic respiratory disease patients completing pulmonary rehabilitation. Change in CCQ with pulmonary rehabilitation was correlated with change in the other questionnaires. The minimum important difference of the CCQ was calculated using distribution and anchor-based approaches. Results: The CCQ, CAT, CRQ and SGRQ improved significantly with rehabilitation with effect sizes of −0.43, −0.26, 0.62, −0.37. Change in CCQ correlated significantly with CAT, CRQ and SGRQ (r = 0.53, −0.64, 0.30, all P < 0.0001).The minimum important difference was −0.42 at the population level and −0.4 at the individual level. Conclusions: The CCQ is responsive to pulmonary rehabilitation in chronic respiratory disease patients, with an MID estimated at −0.4 at the individual level. Key words: Clinical Chronic Obstructive Pulmonary Disease Questionnaire, chronic obstructive pulmonary disease, chronic respiratory disease, health-related quality of life, pulmonary rehabilitation. Abbreviations: AUC, area under curve; BMI, body mass index; CAT, COPD Assessment Test; CCQ, Clinical Chronic Correspondence: Jane Canavan, Department of Respiratory Medicine, Harefield Hospital, Hill End Road, Harefield UB9 6JH, UK. Email: [email protected] Received 16 April 2014; invited to revise 11 May 2014; revised 22 May 2014; accepted 22 May 2014 (Associate Editor: Bob Hancox). Article first published online: 14 August 2014 © 2014 Asian Pacific Society of Respirology

SUMMARY AT A GLANCE This paper describes the use of the CCQ in patients with chronic respiratory disease (non-chronic obstructive pulmonary disease (COPD) ) to determine health-related quality of life, the response of the CCQ to pulmonary rehabilitation, and provides an estimate of the minimum important difference at the individual and population level.

Obstructive Pulmonary Disease Questionnaire; CI, confidence interval; COPD, chronic obstructive pulmonary disease; CRQ, Chronic Respiratory Questionnaire; FEV1, forced expiratory volume in one second; FVC, forced vital capacity; GRCQ, Global Rating of Change Question; ISW, incremental shuttle walk; M:F, male : female; MID, minimum important difference; ROC, receiver operating characteristic; SD, standard deviation; SEM, standard error of measurement; SGRQ, St George’s Respiratory Questionnaire.

INTRODUCTION The Clinical Chronic Obstructive Pulmonary Disease Questionnaire (CCQ) is a short, 10-item selfadministered, easy to complete outcome measure (Fig. 1),1 which assesses health-related quality of life. It consists of three domains (symptoms, functional and mental state) and scores for each domain range from 0 (asymptomatic/no limitation) to 6 (extremely symptomatic/totally limited). The overall CCQ total score is calculated by summing the scores from the 10 questions and dividing this by the number of items. This generates an overall COPD clinical control score from 0 (very good control) to 6 (extremely poor control). It was originally developed in patients with chronic obstructive pulmonary disease (COPD) through interviews and focus group discussions to generate relevant items, followed by item reduction by a panel of international clinicians and experts in the management of COPD.1 Subsequent studies have demonstrated that the CCQ is valid, reliable, responsive to change and correlates well with other healthrelated quality of life measures in patients with COPD, Respirology (2014) 19, 1006–1012 doi: 10.1111/resp.12350

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The CCQ in chronic respiratory disease

Figure 1 Weekly version of the Clinical COPD Questionnaire (CCQ). The CCQ is copyrighted. It may not be altered, sold (paper or electronic), traded or adapted for another medium without the permission of T. Van der Molen, Department of General Practice, University Medical Center, Groningen, Postbus 196, 9700 AD Groningen, The Netherlands.

and the minimum important difference (MID) has been estimated to be a 0.4 point change.1–3 The International Primary Care Respiratory Group rated the CCQ highly in the primary care setting due to its simplicity and psychometric properties,4 and indirect evidence suggests that patients find the CCQ easier to complete than other similar measures.5,6 Furthermore, the latest Global Initiative for Chronic Obstructive Lung Disease guidelines suggest the use of the CCQ, the COPD Assessment Test (CAT)7 or the Medical Research Council Dyspnoea scale8 to assess symptom burden and guide the management of patients with COPD.9 Health-related quality of life is frequently measured in the pulmonary rehabilitation setting. Increasing numbers of chronic respiratory disease patients without COPD are referred to rehabilitation, but unlike COPD, there is a paucity of disease-specific healthrelated quality of life questionnaires. We have recently described the use of the CAT in an unselected, nonCOPD, chronic respiratory disease population and shown that it is immediately responsive to rehabilitation and correlates with change in other measures.10 In © 2014 Asian Pacific Society of Respirology

contrast, the CCQ has not been previously used in an unselected chronic respiratory population. The aims of the current study were to determine if: (i) the CCQ correlates with other health-related quality of life measures in a chronic respiratory disease population; (ii) the CCQ is responsive to rehabilitation in chronic respiratory disease patients attending pulmonary rehabilitation; (iii) the change in CCQ with pulmonary rehabilitation correlates with the change in other health-related quality of life questionnaires; (iv) the MID of the CCQ in chronic respiratory disease is similar to estimates in patients with COPD. We hypothesized that the CCQ is a responsive measure in patients with chronic respiratory disease and that change would correlate with changes in other well-established health-related quality of life instruments.

METHODS Participants were recruited from those attending the Harefield Pulmonary Rehabilitation Unit between Respirology (2014) 19, 1006–1012

1008 September 2011 and August 2013. Only those with a primary diagnosis of a respiratory disorder, with no coexisting COPD as determined by a respiratory consultant were included. Data were collected prospectively at the initial and end of course assessments. All participants gave written informed consent, and the study was approved by the West London and the London-Camberwell St Giles Research Ethics Committee. The rehabilitation programme comprised two supervised sessions per week for 8 weeks, with encouragement to complete at least 1 h of unsupervised home exercise each week. Each supervised session consisted of 1 h of exercise and 1 h of education with an emphasis on self-management. Exercise sessions consisted of aerobic exercise including walking and cycle ergometry at an initial prescription of 60–80% predicted VO2max which was increased according to dyspnoea score on the Borg breathlessness scale11 as well as resistance training of the upper and lower limbs. The weekly version of the CCQ was prospectively measured before and after pulmonary rehabilitation. Aerobic exercise capacity was assessed using the incremental shuttle walk (ISW), with the furthest of two walks, separated by at least a 30-min rest, recorded as previously described,12 while health-related quality of life was measured using the St George’s Respiratory Questionnaire (SGRQ), the self-reported Chronic Respiratory Questionnaire (CRQ) and the COPD Assessment Test. Lung function was assessed using a handheld spirometer (EasyOne, Model 2001, NDD Medizintechnik AG, Zurich, Switzerland). After the rehabilitation course, all patients were asked to complete a Global Rating of Change Question (GRCQ) which self-rated the improvement in their overall condition following rehabilitation with one of five responses (1 = I feel much better, 2 = I feel a little better, 3 = I feel no different, 4 = I feel a little worse, 5 = I feel much worse). Patients were blinded to the results of other outcome measures from the end of course assessment until the GRCQ was completed.

Statistical analysis Data analyses were performed using SPSS (version 21, IBM, Armonk, NY, USA) and GraphPad Prism 5 (GraphPad Software, San Diego, CA, USA). Paired t-tests or Wilcoxon signed-rank tests were used to assess data from pre- to post-rehabilitation. Independent t-tests or Mann Whitney U-tests were used to analyse the change in outcome measures with pulmonary rehabilitation. Relationships between baseline variables and the change in CCQ and that of other health outcome measures with pulmonary rehabilitation were calculated using Pearson’s correlation coefficient. Cohen’s d effect sizes were calculated using the mean and standard deviation of data collected at the initial and at the end of course assessment. Cohen suggested that a small effect size is defined as 0.2, medium is 0.5 and large 0.8.13 Data are presented as mean (standard deviation (SD)) or median (25th, 75th percentiles) where variables were not normally distributed. Respirology (2014) 19, 1006–1012

JL Canavan et al.

The minimum important difference (MID) of the CCQ was determined using anchor and distributionbased approaches. For anchor-based approaches, change in external anchor had to correlate significantly with change in CCQ with a correlation coefficient of at least 0.3 as previously described.14 Linear regression analysis was used to calculate the mean (95% confidence interval (CI) ) change in CCQ corresponding to the established minimum important improvement of the anchor (SGRQ: 4-point reduction);15 CAT (2-point reduction),16 CRQ total and CRQ domains (mean 0.5-point increase).17 Mean (95% CI) change in CCQ for those scoring ‘2’ (a little better) on the GRCQ was also calculated. To determine the MID of the CCQ at an individual level, we plotted receiver operating characteristic (ROC) curves to determine the change in CCQ score with the best balance of sensitivity and specificity to identify patients who had ‘improved’ by the established MID of the anchor, as previously described.16,18 For distribution-based methods, we calculated half the (0.5) and the standard error of measurement (SEM)16 assuming that intraclass correlation coefficient for test–retest reliability of the CCQ is 0.94.1

RESULTS Baseline relationships One hundred and thirty-eight patients with chronic respiratory disease completed pulmonary rehabilitation during the study period. Disease classifications were interstitial lung disease (n = 39), asthma (n = 32), bronchiectasis (n = 40), extra-thoracic restriction such as chest wall disease, respiratory muscle weakness or obesity hypoventilation (n = 26) and lung cancer (n = 1). Baseline characteristics are detailed in Table 1. During this time, 51 further patients attended for an initial assessment and did not complete the pulmonary rehabilitation course. Mean (95% CI) CCQ at baseline was 2.9 (1.4) in these patients which was significantly higher than that found in the completers (mean difference (95% CI) 0.37 (0.02 to 0.78), P = 0.043). Correlations between the CCQ total score and other health-related outcome measures at baseline are shown in Figure 2. CCQ was significantly correlated to the CAT, SGRQ and CRQ (r = 0.79, r = 0.69, r = −0.76; all P < 0.0001). These significant correlations persisted when data were analysed stratified to disease category. Response to pulmonary rehabilitation There were statistically significant changes in exercise capacity, CRQ, SGRQ and CAT with pulmonary rehabilitation (Table 1). Mean (95% CI) change in CCQ with rehabilitation was −0.47 (−0.64 to −0.30); P < 0.0001. Effect size for the CCQ, CAT, CRQ and SGRQ were −0.43, −0.26, 0.62 and −0.37, respectively. Correlations between the change in CCQ and the other health-related quality of life measures are reported in Table 2. Minimum important difference (MID) Mean change (95% CI) in CCQ total score according to response to the GRCQ are shown in Figure 3. For those © 2014 Asian Pacific Society of Respirology

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The CCQ in chronic respiratory disease Table 1 Participant characteristics at baseline and response to Pulmonary Rehabilitation Characteristic Age (years) MRC Sex (M : F) Smoking Pack years FEV1 (L) FEV1 (% predicted) FVC (L) FVC (%) FEV1/FVC ratio BMI (kg/m2) CCQ Symptoms CCQ Functional CCQ Mental CCQ Total CRQ Dyspnoea CRQ Fatigue CRQ Emotion CRQ Mastery CRQ Total CAT SGRQ Symptoms SGRQ Activities SGRQ Impact SGRQ Total ISW (m)

Baseline value

Mean (95%CI) change

P-value

67 (12) 3 (1) 72:66 0 (0 to 5) 1.82 (0.7) 71 (22) 2.49 (0.9) 73 (20) 0.7 (0.1) 28.7 (25.3 to 34.2) 2.2 (1.1) 1.9 (1.3) 1.8 (1.5) 2.5 (1.1) 3.3 (1.3) 3.5 (1.3) 4.5 (1.3) 5.0 (1.4) 4.1 (1.8) 18.5 (7.1) 58.05 (22.0) 62.85 (25.1) 32.43 (17.2) 45.94 (17.8) 260 (110 to 380)

−0.38 (−0.57 to −0.20) −0.51 (−0.72 to −0.31) −0.52 (−0.77 to −0.27) −0.47 (−0.64 to −0.30) 0.78 (0.59 to 0.97) 0.56 (0.38 to 0.76) 0.51 (0.34 to 0.68) 0.31 (0.12 to 0.51) 0.55 (0.41 to 0.69) −2.15 (−3.28 to −1.03) −4.59 (−7.53 to −1.65) −7.16 (−10.65 to −3.67) −5.27 (−7.97 to 2.57) −5.71 (−8.23 to −3.20) 80 (60 to 90)

Clinical COPD Questionnaire in patients with chronic respiratory disease.

The Clinical Chronic Obstructive Pulmonary Disease (COPD) Questionnaire (CCQ) is an easy to complete, health-related quality of life questionnaire whi...
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