tests of the responsiveness of the copd assessment test following acute exacerbation and pulmonary...

134

CHEST Original ResearchCOPD

Original Research

COPD health status measurements, such as the St. George Respiratory Questionnaire (SGRQ) 1

and Chronic Respiratory Questionnaire (CRQ), 2 pro-vide complementary information to that obtained from spirometry. Although they have an established place in clinical trials, they have not been incorpo-rated into routine clinical assessment. One factor

may be their length and complexity. The COPD Clin-ical Questionnaire (CCQ) 3 is a shorter instrument that can be used in routine care, but its develop-ment preceded current standards recommended for patient-reported outcome development. 4 The COPD Assessment Test (CAT) was developed to meet the perceived need for a simple instrument that could provide reliable measurement of COPD health status

Background: The COPD Assessment Test (CAT) is an eight-item questionnaire suitable for rou-tine clinical use that shows reliability and validity in stable and exacerbating COPD. Methods: Study 1 assessed CAT responsiveness to changes in health status in 67 patients during an exacerbation (days 1-14). Study 2 assessed CAT responsiveness in 64 patients undergoing pul-monary rehabilitation (days 1-42). Correlations between CAT and other outcome measures were examined. Results: In study 1, mean 14-day improvement in CAT score was 2 1.4 � 5.3 units ( P 5 .03). In patients judged to be responders (clinician defi ned) change in score was 2 2.6 � 4.4; in nonre-sponders it was 2 0.2 � 5.9. In study 2, the mean improvement in CAT score was 2 2.2 � 5.3 ( P 5 .002); the effect size for the change was 2 0.33. Effect size for changes in the Chronic Respi-ratory Questionnaire—Self Administered Standardized (CRQ-SAS) form domain scores ranged from 2 0.02 to 0.34. Change in 6-min walk distance (6MWD) was 41 � 55 m. CAT and CRQ-SAS domain scores correlated at baseline ( r 5 2 0.54 to 2 0.69, P , .0001) and in terms of change fol-lowing pulmonary rehabilitation ( r 5 2 0.39 to 2 0.63, P , .01). Correlations were less strong between change in the CAT and St. George Respiratory Questionnaire for COPD in study 1 ( r , 0.24) and for 6MWD ( r , 0.11) in study 2. Conclusions: These studies indicate that the CAT is sensitive to changes in health status follow-ing exacerbations and is as responsive to pulmonary rehabilitation as more complex COPD health status measures. CHEST 2012; 142(1):134–140

Abbreviations: 6MWD 5 6-min walk distance; ANOVA 5 analysis of variance; CAT 5 COPD Assessment Test; CRQ-SAS 5 Chronic Respiratory Questionnaire—Self-Administered Standardized; ES 5 effect size; GOLD 5 Global Initiative for Chronic Obstructive Lung Disease; MCID 5 minimal clinically important difference; mMRC 5 modifi ed Medical Research Council; PR 5 pulmonary rehabilitation; RPE 5 Borg rating of perceived exertion; SGRQ-C 5 St. George Respiratory Questionnaire for COPD

Tests of the Responsiveness of the COPD Assessment Test Following Acute Exacerbation and Pulmonary Rehabilitation Paul W. Jones , PhD ; Gale Harding , MA ; Ingela Wiklund , PhD ; Pamela Berry , MSc ; Maggie Tabberer , MSc ; Ren Yu , MA ; and Nancy K. Leidy , PhD

Manuscript received February 11, 2011; revision accepted December 9, 2011 . Affi liations: From the Division of Clinical Science (Dr Jones), St. George’s University of London, London, England; the Center for Health Outcomes Research (Mss Harding and Yu and Dr Leidy), United Biosource Corporation, Bethesda, MD; the Center for Health Outcomes Research (Dr Wiklund), United BioSource Corporation, London, England; and Global Health Outcomes (Mss Berry and Tabberer), GlaxoSmithKline, London, England .

Funding/Support: This study was supported by GlaxoSmithKline . Correspondence to: Paul W. Jones, PhD , Division of Clinical Science, St. George’s University of London, Cranmer Terr, London, SW17 0RE, England; e-mail: [email protected] © 2012 American College of Chest Physicians. Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details. DOI: 10.1378/chest.11-0309

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relating to coughing, mucus production, chest tightness, capacity for exercise and activities, confi dence, sleep quality, and energy levels. The scaling range is from 0 to 40. The CAT form is included as e-Appendix 2.

Study 1 (Exacerbation)

At visit 1 (baseline) patients performed spirometry, provided demographic and smoking history, and completed the CAT and the modifi ed Medical Research Council (mMRC) dyspnea scale. 8 They also completed the SGRQ-C, 9 a shortened version of the SGRQ specifi c for COPD. SGRQ-C scores are directly compa-rable to those obtained with the original version and are thus termed SGRQ scores. At visit 2 (day 14), the patients completed the CAT and the SGRQ-C. At this visit, the clinician and patient independently completed global ratings of change in COPD since the last visit; to avoid bias, the patient completed this item prior to meeting with the physician. Change was determined using a six-point single-item instrument classifying change as “much worse,” “worse,” “no change,” “better,” “much better,” or “com-pletely resolved.” Responders were defi ned as having a global rating of change in COPD since last visit of “better,” “much better,” or “completely resolved.” Nonresponders were defi ned as having a global rating of change in COPD since last visit of “no change,” “worse,” or “much worse.”

Study 2 (Rehabilitation)

At visit 1 (baseline), patients performed spirometry; com-pleted the CAT, mMRC dyspnea scale, SGRQ-C, and CRQ-Self Administered Standardized (CRQ-SAS) forms 10 ; and performed a 6-min walk distance (6MWD) test. 11 The Borg scale for breath-lessness 12,13 was administered before and at completion of the 6MWD. The Borg rating of perceived exertion (RPE) 14,15 was administered immediately on completion of the 6MWD test. At visit 2 (day 42 � 7), patients completed the CAT and CRQ-SAS and performed the 6MWD test.

Statistical Analyses

Sociodemographic and clinical characteristics of patients were summarized descriptively. SAS software, version 9.1 (SAS Institute) was used for statistical analysis. Data are reported as mean � SD. The level of statistical signifi cance was set at 0.05 (two-sided). In both studies, changes in measured variables were tested using analysis of covariance. To compare changes in CAT score with changes in other measures, the effect size (ES) (defi ned as mean change/SD at baseline) was calculated for each variable. Construct validity (associations between CAT scores and selected patient-reported and clinical COPD severity measures) were tested using Spearman r and Pearson r as appropriate. Group comparisons were tested using analysis of variance (ANOVA) or t tests.

Results

Study Population

Demographic and clinical characteristics and main-tenance therapies for patients at visit 1 for both studies are shown in Table 1 . The patients’ ages ranged from 42 years (study 1) and 44 years (study 2) to 81 years (both studies), but the average age was similar in both studies (median age: study 1, 66 years; study 2, 69 years). Baseline FEV 1 and mMRC dyspnea scores were similar across the two studies.

in patients within a routine clinical practice setting. 5,6 Initial validation studies demonstrated evidence of good internal validity and a strong correlation ( r 5 0.80) with SGRQ-C score in stable patients. 5 The studies described here were designed to test the responsive-ness of the CAT to changes in COPD health status under two conditions commonly seen in clinical prac-tice: recovery from an exacerbation and response to pulmonary rehabilitation (PR).

Materials and Methods

Patients

Two patient cohorts were investigated in separate studies: Study 1 (changes in COPD health status during recovery from exacerbation; United BioSource Corp study code A2-8397-000) included 67 patients with a clinician-diagnosed exacerbation, recruited from 11 primary care and three pulmonary clinical sites in the United States from February to April 2009. Study 2 (changes in COPD health status following pulmonary rehabili-tation; United BioSource Corp study code A2-8397-001) included 64 patients with stable COPD at the start of their rehabilitation, recruited from six pulmonary rehabilitation sites in Canada and the United States from July to December 2009. A full list of all study sites is provided in e-Appendix 1. Both studies were approved by local ethics review committees and conducted in accordance with the Declaration of Helsinki and Good Clinical Practice guidelines (approval numbers, 455-12-08 for acute patients [Study A2-8397-000] and 462-02-09 for rehabilitation patients [Study A2-8397-001]).

Study 1 (Exacerbation) Entry Criteria

Patients were aged 40 to 80 years with a physician diagnosis of COPD (including emphysema or chronic bronchitis). Disease severity was established according to GOLD (Global Initiative for Chronic Obstructive Lung Disease) guidelines. 7 Recruitment and enrollment were monitored to yield samples of 15% each of patients defi ned as GOLD stages I and IV and 35% each in GOLD stages II and III prior to the exacerbation. The patients were recruited on the day they presented with an acute exacerbation, which was clinician diagnosed and defi ned as the requirement for oral corticosteroids and/or antibiotics in response to increased symptoms for � 2 days, with or without hospitalization. In addi-tion, patients had to be able to read and understand English. Patients not meeting the inclusion criteria or with a primary diagnosis of asthma; other active chronic respiratory disease requiring treatment, intervention, or diagnostics; or any other severe or uncontrolled comorbidities were excluded.

Study 2 (Rehabilitation) Entry Criteria

Inclusion and exclusion criteria (including GOLD stage) were the same as for study 1, except that patients had to be stable and referred for 6 weeks of PR. Additionally, patients were excluded if they were receiving PR for reasons other than COPD or had a history of unstable angina or myocardial infarction during the preceding month, resting heart rate . 120 beats/min, systolic BP . 180 mm Hg, or diastolic BP . 100 mm Hg.

Study Measures and Design

A full description of the CAT has been published previously. 5 Briefl y, it consists of eight items scored from 0 (best) to 5 (worst)


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136 Original Research

improved signifi cantly (mean change 2 1.4, P 5 .03), whereas no signifi cant improvement was observed overall in SGRQ score ( Table 2 ). There was a sig-nificant correlation between patient-rated global response and change in CAT score ( r 5 2 0.35, P 5 .004). In the patient-judged “responders” (n 5 33), the mean change in CAT score was 2 2.8 � 4.6 units. In the nonresponders (n 5 32), the mean change was 0.0 � 5.6 units; the difference between these two change scores was signifi cant ( P 5 .03) ( Fig 1 ). A min-imal clinically important difference (MCID) is yet to be established for the CAT, so to gauge the range of changes in CAT score seen during recovery from an exacerbation, the proportion of patients achieving an improvement of � 1, � 2, or � 3 CAT units was calculated. Within the patient-judged responder group these proportions were 67% ( � 1), 62% ( � 2), and 48% ( � 3 CAT units).

There was a signifi cant correlation between the global ratings of change assessed by patients and cli-nicians ( r 5 0.51, P , .0001). The pattern of change in CAT scores in patients defi ned by clinicians as responders (n 5 34) or nonresponders (n 5 31) was similar: the mean change was 2 2.6 � 4.4 units in clinician-defi ned responders and 2 0.2 � 5.9 units in clinician-defi ned nonresponders; the difference between the two change scores was not signifi cant P 5 .08 ( Fig 1 ). There was a signifi cant correlation between clinician-rated global response and change in CAT score ( r 5 2 0.34, P 5 .006).

The correlation between change in CAT score and change in SGRQ score was not statistically sig-nifi cant ( r 5 0.24, P 5 .06), but the SGRQ change was different between patient-judged responders and non-responders: 2 2.1 � 7.3 units vs 2.8 � 9.1 units; P 5 .022. In comparative terms, the change in CAT score in the patient-judged responders was 7.0% of the scal ing range of the instrument, compared with 2.6% for the SGRQ.

Study 2 (Rehabilitation)

At baseline, the CAT correlated well with CRQ-SAS domains and SGRQ scores ( Table 3 ). Figure 2 shows scatter plots of the significant correlations between CAT scores and the individual domains of the CRQ-SAS. Correlations with Borg scores, 6MWD, and mMRC dyspnea scale grades were weaker but statistically signifi cant ( Table 3 ). There was no signifi cant correlation with FEV 1 expressed as % predicted.

CAT scores improved between days 1 and 42, with a mean change of 2 2.2 � 5.3 units ( P 5 .002). Changes in all measured variables and their associated ES are shown in Table 4 . The ES for CAT change score was similar to that for 6MWD and the fatigue, emotional

Study 1 (Exacerbation)

There was a strong correlation between CAT score and SGRQ score at baseline ( r 5 0.75, P , .0001), and the correlation was similarly strong on day 14 ( r 5 0.73, P , .0001). Over 14 days, the mean CAT score

Table 1— Demographic and Clinical Characteristics of Patients

Characteristics

Study 1, Acute Exacerbation

(N 5 67) a

Study 2, Pulmonary

Rehabilitation (N 5 64)

Demographics Age, y Mean (SD) 64 (9) 67 (8) Sex, female 34 (51) 25 (39) Race/ethnicity White b 60 (90) 58 (91) Other b 8 (12) 6 (9) Current smoker 19 (28) 11 (17) BMI, mean (SD) nr 27.4 (6.0)GOLD stage I mild COPD 7 (10) 10 (16) II moderate COPD 18 (27) 31 (48) III severe COPD 30 (45) 16 (25) IV very severe COPD 10 (15) 7 (11) Missing 2 (3) 0 (0)Pulmonary function, mean (SD) FEV 1 , L 1.3 (0.6) 1.4 (0.6) FEV 1 , % predicted 47 (21) 50 (17) FVC, L 2.4 (0.9) 2.8 (1.0)mMRC dypsnea scale grade c 0 5 (8) 8 (13) 1 29 (43) 24 (38) 2 20 (30) 19 (30) 3 10 (15) 7 (11) 4 3 (5) 0 (0) Missing 0 (0) 6 (9)Exercise capacity Mean 6MWD, m (SD) n/a 271.1 (131.8) Mean modifi ed Borg dyspnea

scale, pre-6MWD (SD)n/a 1.3 (1.33)

Mean modifi ed Borg dyspnea scale, post-6MWD (SD)

n/a 2.9 (1.33)

Mean Borg RPE (SD) n/a 11.6 (2.66)Maintenance therapies b SABA or SAMA 50 (75) 57 (89) LABA or LAMA 41 (61) 41 (64) ICS or LABA 1 ICS 50 (75) 50 (78) OCS 22 (33) 22 (33) LTOT 17 (25) 17 (25)

Data given as No. (%) unless otherwise indicated. 6MWD 5 6-min walk distance; GOLD 5 Global Initiative for Chronic Obstructive Lung Disease; ICS 5 inhaled corticosteroid; LABA 5 long-acting b 2 agonist; LAMA 5 long-acting antimuscarinic agent; LTOT 5 long-term oxygen therapy; mMRC 5 modifi ed Medical Research Council; n/a 5 not applicable; nr 5 not reported; OCS 5 oral corticosteroid; RPE 5 rating of perceived exertion; SABA 5 short-acting b 2 agonist; SAMA 5 short-acting antimuscarinic agent. a Two patients contributed to baseline measurements but did not complete visit 2. b Data are not mutually exclusive. c Data for one patient were missing from study 2.



further evaluation and/or treatment change. In patients who were judged, either by themselves or their cli-nician, to be clinical responders, almost one-half had an improvement of � 3 units.

The size of change in CAT score seen following pulmonary rehabilitation was very similar to that reported in a recently published study. 16 The effect size calculated for the CAT following pulmonary rehabilitation was very similar to those for the fatigue, emotional function, and mastery domains of the CRQ-SAS and the 6MWD. No formal estimate has yet been made of the MCID for the CAT, but since the correlation between CAT and SGRQ is very good, it is reasonable to carry out a mapping exer-cise to estimate the size of difference in CAT score associated with the 4-unit MCID for the SGRQ. This estimate (which would only apply at a group, rather than individual patient, level) is 1.6 CAT units; thus, the measured change with rehabilitation in this study is 1.4 times the currently estimated MCID. These observations suggest that the CAT is a sensitive instru-ment that could be used routinely to evaluate the

function, and mastery domains of the CRQ-SAS, but not for the dyspnea domain, which did not change in this study.

Change in CAT scores correlated signifi cantly with changes in CRQ-SAS domain scores ( Fig 3 , Table 5 ). However, correlations with changes in Borg scores and the 6MWD were nonsignifi cant ( Table 5 ).

Discussion

This study has shown that the CAT is responsive to changes in COPD health status during recovery fol-lowing a COPD exacerbation and in response to PR. It demonstrated good responsiveness in assessing changes to COPD health status during recovery from an exacerbation. The change in CAT score over the fi rst 14 days of recovery from an exacerbation also distinguished between clinical responders and nonresponders, when response was defi ned either by the patient or by the clinician. This is an important observation, since it shows that, in routine practice, an improvement in the CAT score is to be expected within 14 days of treatment of responders; no change or worsening CAT score will suggest the need for

Figure 1. Study 1 (exacerbation): box plots showing change in CAT score on day 14 according to response/nonresponse to treat-ment of exacerbation, based on ratings of COPD change by patient and clinician. Patient responders: n 5 33; nonresponders: n 5 32, difference in mean change 5 2.75, P 5 .03 ( t test). Clini-cian responders: n 5 34; nonresponders: n 5 31, difference in mean change 5 2.4, P 5 .08 ( t test). CAT scaling range 0-40, higher score indicates poorer health. CAT 5 COPD Assessment Test.

Table 3— Correlations Between CAT Scores and Patient/Clinician Assessments at Baseline (Study 2)

Assessment Correlation P Value

Patient completed a CRQ-SAS (n 5 64) Dyspnea 2 0.65 , .0001 Fatigue 2 0.62 , .0001 Emotional function 2 0.54 , .0001 Mastery 2 0.69 , .0001 SGRQ (n 5 64) 0.69 , .0001 Modifi ed Borg dyspnea

scale: pre-6MWD b (n 5 121)0.33 .002

Modifi ed Borg dyspnea scale: post-6MWD b (n 5 121)

0.38 , .0001

Borg RPE b (n 5 117) 0.36 , .0001Clinician completed b FEV 1 , % predicted (n 5 61) 2 0.23 .07 GOLD stage (n 5 64) 0.27 .03 mMRC dyspnea scale (n 5 63) 0.42 .0007 6MWD (n 5 121) 2 0.24 .009 No. exacerbations in past 12 mo (n 5 63) 2 0.12 .3

CRQ-SAS 5 Chronic Respiratory Questionnaire—Self-Administered Standardized. See Table 1 and 2 legends for expansion of other abbreviations. a Pearson correlation unless otherwise indicated. b Spearman rank order correlation unless otherwise indicated.

Table 2— Overall Changes in CAT and SGRQ-C Scores (Study 1)

Assessment Visit 1, Mean (SD) Visit 2, Mean (SD) Change in Score, Mean (SD) t Value, ANOVA P Value, ANOVA Effect Size

CAT (No. 5 65) 21.44 (7.7) 19.9 (7.7) 2 1.4 (5.3) 2 2.20 .03 2 0.19SGRQ (No. 5 64) 55.0 (21.4) 54.9 (20.4) 0.3 (8.5) 0.31 .8 0.016

Two patients contributed to baseline measurements but did not complete visit 2. ANOVA 5 analysis of variance; CAT 5 COPD Assessment Test; SGRQ 5 St. George Respiratory Questionnaire.




This study further extends evidence for the conver-gent validity of the CAT, since it demonstrated good correlations with all domains of the CRQ-SAS both between patients and longitudinally within patients. This is an important observation, because the CAT was designed to provide a measure of overall COPD health status, and the correlations seen with the four domains of the CRQ-SAS suggest that it does capture a wide range of effects of COPD on the patient, from dyspnea to mastery.

impact of rehabilitation programs more easily than the more time-consuming and complex measures that are used currently. The size of change in CAT score seen in the responders in the fi rst 14 days following an exacerbation clearly exceeded the provisional esti-mate of the MCID of the CAT by at least a factor of two. Finally, it should be noted that the changes seen in these two studies may have been greater if the patients had been followed for longer after their exacerbation or had a longer period of rehabilitation.

Figure 2. Study 2 (pulmonary rehabilitation): scatter plot of baseline Pearson correlations between CAT score and the individual domains of CRQ-SAS. All signifi cant at P , .0001. A, Correlation between CAT score and dyspnea domain of the CRQ-SAS ( r 5 2 0.65). B, Correlation between CAT score and fatigue domain of the CRQ-SAS ( r 5 2 0.62). C, Correlation between CAT score and emotion domain of the CRQ-SAS ( r 5 2 0.54). D, Correlation between CAT score and mastery domain of the CRQ-SAS ( r 5 2 0.69). CRQ-SAS 5 Chronic Respiratory Questionnaire—Self-Administered Standardized. See Figure 1 legend for expansion of other abbreviation.

Table 4— Changes in CAT and CRQ-SAS Scores and 6MWD Following Pulmonary Rehabilitation (Day 42, Study 2)

Assessment No. Visit 1 Visit 2 Change in Score t Test P Value Effect Size

CAT 59 17.9 � 6.5 15.7 � 6.9 2 2.2 � 5.3 .002 2 0.33CRQ-SAS 59 Dyspnea … 5.0 � 1.4 5.0 � 1.3 2 0.03 � 1.2 .9 2 0.02 Fatigue … 3.9 � 1.2 4.4 � 1.2 0.4 � 0.8 .0003 0.24 Emotional function … 4.8 � 1.2 5.0 � 1.2 0.3 � 0.8 .007 0.34 Mastery … 4.9 � 1.5 5.3 � 1.3 0.4 � 1.0 .005 0.276MWD, m 57 271.1 � 132.8 321.4 � 121.5 41.1 � 55.3 , .0001 0.31Postexercise Borg dyspnea score 57 2.9 � 1.3 2.8 � 1.6 2 0.04 � 1.5 .9 0.0Borg RPE 53 11.3 � 2.7 10.9 � 2.5 2 0.9 � 2.1 .002 2 0.35

Data are presented as mean � SD unless otherwise noted. FEV 1 , SGRQ, and mMRC dyspnea scale were assessed at the fi rst visit only; therefore, there are no data on changes in these parameters. See Table 1-3 legends for expansion of abbreviations.



makes detection of a signifi cant correlation between changes in score very diffi cult without very large sample sizes. The weak correlation of the baseline CAT score with FEV 1 % predicted in the PR group was expected from earlier reports. 5 However, the low correlation between change in the CAT score and change in 6MWD was less expected, since a slightly higher correlation of 0.31 has been reported recently 16 ; however, in that study the effect size for the 6MWD was 0.71 compared with 0.31 here.

In conclusion, the CAT is a short, reliable, and valid tool for monitoring COPD health status over time. It can quantify COPD health status gain with reha-bilitation and is responsive to recovery from an exac-erbation. The robust methods used in its develop ment should ensure that its measurement properties are consistent across a wide range of disease severity, and the multilingual development processes that were used should ensure that the observations made in this study are generalizable to other countries/lan-guages, provided a properly translated version is used.

Acknowledgments Author contributions: Dr Jones vouches for the veracity and completeness of the data and the data analyses.

Our estimates of the CAT’s responsiveness may be conservative, since it has been shown that full health status recovery takes many weeks. 17 Furthermore, greater responsiveness to rehabilitation may have been observed if the program had been longer and we had been able to follow the patients for longer. There were some fi ndings that warrant discussion. First, the correlation between change in CAT and change in SGRQ score following exacerbation recov-ery was weak. This is unsurprising, since the mean and range of changes in both scores were small, which

Figure 3. Study 2 (pulmonary rehabilitation): scatter plot of Pearson correlation between change in CAT scores and change in the scores of the individual domains of CRQ-SAS. A, Correlation between change in CAT scores and change in dyspnea domain scores of the CRQ-SAS ( r 5 2 0.53, P , .0001). B, Correlation between change in CAT scores and change in fatigue domain scores of the CRQ-SAS ( r 5 2 0.63, P , .0001). C , Correlation between change in CAT scores and change in emotion domain scores of the CRQ-SAS ( r 5 2 0.39, P 5 .002). D, Correlation between change in CAT scores and change in mastery domain scores of the CRQ–SAS ( r 5 2 0.45, P 5 .0003). See Figure 1 and 2 legends for expansion of abbreviations.

Table 5— Correlations Between Change in CAT Scores and Change in Patient/Clinician Assessments Following

Pulmonary Rehabilitation (Day 42, Study 2)

Assessments No.Pearson

Correlation P Value

CRQ-SAS 59 Dyspnea … 2 0.53 , .0001 Fatigue … 2 0.63 , .0001 Emotional function … 2 0.39 .002 Mastery … 2 0.45 .0003Borg dyspnea scale: postexercise 57 0.15 .3Borg RPE 53 0.24 .086MWD 57 2 0.11 .4

See Tables 1 and 3 for expansion of abbreviations.




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4 . Patrick DL , Burke LB , Powers JH , et al . Patient-reported outcomes to support medical product labeling claims: FDA perspective . Value Health . 2007 ; 10 ( suppl 2 ): S125 - S137 .

5 . Jones PW , Harding G , Berry P , Wiklund I , Chen WH , Kline Leidy N . Development and fi rst validation of the COPD Assessment Test . Eur Respir J . 2009 ; 34 ( 3 ): 648 - 654 .

6 . Jones P , Harding G , Wiklund I , Berry P , Leidy N . Improving the process and outcome of care in COPD: development of a stan-dardised assessment tool . Prim Care Respir J . 2009 ; 18 ( 3 ): 208 - 215 .

7 . GOLD executive committee. Global strategy for diagnosis, management, and prevention of COPD. GOLD website. http://www.goldcopd.org . Updated 2009 . Accessed July 1, 2010.

8 . Bestall JC , Paul EA , Garrod R , Garnham R , Jones PW , Wedzicha JA . Usefulness of the Medical Research Council (MRC) dyspnoea scale as a measure of disability in patients with chronic obstructive pulmonary disease . Thorax . 1999 ; 54 ( 7 ): 581 - 586 .

9 . Meguro M , Barley EA , Spencer S , Jones PW . Development and validation of an improved, COPD-specifi c version of the St. George Respiratory Questionnaire . Chest . 2007 ; 132 ( 2 ): 456 - 463 .

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Dr Jones: contributed to developing the study protocol, was a study investigator, interpreted study data, contributed to and reviewed all drafts of the manuscript, and approved the fi nal version of the manuscript. Ms Harding: contributed to developing the study protocol, inter-preted study data, conducted statistical analysis, contributed to and reviewed all drafts of the manuscript, and approved the fi nal version of the manuscript. Dr Wiklund: contributed to developing the study protocol, inter-preted study data, developed the fi rst draft of the manuscript, contributed to and reviewed all drafts of the manuscript, and approved the fi nal version of the manuscript. Ms Berry: contributed to developing the study protocol, inter-preted study data, contributed to and reviewed all drafts of the manuscript, and approved the fi nal version of the manuscript. Ms Tabberer: contributed to developing the study protocol, inter-preted study data, developed the fi rst draft of the manuscript, contributed to and reviewed all drafts of the manuscript, and approved the fi nal version of the manuscript. Ms Yu: contributed to developing the study protocol, interpreted study data, conducted statistical analysis, contributed to and reviewed all drafts of the manuscript, and approved the fi nal ver-sion of the manuscript. Dr Leidy: contributed to developing the study protocol, interpret-ed study data, developed the fi rst draft of the manuscript, contrib-uted to and reviewed all drafts of the manuscript, and approved the fi nal version of the manuscript. Financial/nonfi nancial disclosures: The authors have reported to CHEST the following confl icts of interest: Dr Jones has received consulting fees and speakers honoraria from GlaxoSmithKline. He was not paid for writing the manuscript. Mss Harding and Yu and Drs Wiklund and Leidy are employed by United BioSource Corporation. United BioSource Corporation provides consul-ting and other research services to pharmaceutical, device, gov-ernment, and nongovernment organizations. In this salaried position, they work with a variety of companies and organiza-tions. They received no payment or honoraria directly from these organizations for services rendered and are expressly pro-hibited from engaging in any independent work of this nature Ms Berry has been directly employed or provided consultancy services to the pharmaceutical industry for 15 years and is cur-rently and employee of GlaxoSmithKline. Ms Tabberer has been directly employed or provided consultancy services to the phar-maceutical industry for 10 years and is currently and employee of GlaxoSmithKline . Role of sponsors: GlaxoSmithKline did not place any restric-tions on this study with respect to the decision of the authors to submit this manuscript for publication. Other contributions: Editorial support in the form of develop-ment of draft outline, development of manuscript fi rst draft, edi-torial suggestions to draft versions of this paper, assembling tables and fi gures, collating author comments, copy editing, fact checking, referencing, and graphic services was provided by Geoff Weller, PhD, at Gardiner-Caldwell Communications and was funded by GlaxoSmithKline. COPD Assessment Test and its associ-ated CAT logo is a trademark of the GlaxoSmithKline group of companies. Additional information: The e-Appendixes can be found in the “Supplemental Materials” area of the online article.


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