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Tests of the Responsiveness of the COPD Assessment Test Following Acute Exacerbation and Pulmonary RehabilitationCOPD Assessment Test Responsiveness FREE TO VIEW

Paul W. Jones, PhD; Gale Harding, MA; Ingela Wiklund, PhD; Pamela Berry, MSc; Maggie Tabberer, MSc; Ren Yu, MA; Nancy K. Leidy, PhD
Author and Funding Information

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.

Correspondence to: Paul W. Jones, PhD, Division of Clinical Science, St. George’s University of London, Cranmer Terr, London, SW17 0RE, England; e-mail: pjones@sgul.ac.uk

Financial/nonfinancial disclosures: The authors have reported to CHEST the following conflicts 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 consulting and other research services to pharmaceutical, device, government, and nongovernment organizations. In this salaried position, they work with a variety of companies and organizations. They received no payment or honoraria directly from these organizations for services rendered and are expressly prohibited 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 currently and employee of GlaxoSmithKline. Ms Tabberer has been directly employed or provided consultancy services to the pharmaceutical industry for 10 years and is currently and employee of GlaxoSmithKline.

Role of sponsors: GlaxoSmithKline did not place any restrictions on this study with respect to the decision of the authors to submit this manuscript for publication.

Funding/Support: This study was supported by GlaxoSmithKline.


Funding/Support: This study was supported by GlaxoSmithKline.

Reproduction of this article is prohibited without written permission from the American College of Chest Physicians. See online for more details.


Chest. 2012;142(1):134-140. doi:10.1378/chest.11-0309
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Background:  The COPD Assessment Test (CAT) is an eight-item questionnaire suitable for routine 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 pulmonary 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 −1.4 ± 5.3 units (P = .03). In patients judged to be responders (clinician defined) change in score was −2.6 ± 4.4; in nonresponders it was −0.2 ± 5.9. In study 2, the mean improvement in CAT score was −2.2 ± 5.3 (P = .002); the effect size for the change was −0.33. Effect size for changes in the Chronic Respiratory Questionnaire—Self Administered Standardized (CRQ-SAS) form domain scores ranged from −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 = −0.54 to −0.69, P < .0001) and in terms of change following pulmonary rehabilitation (r = −0.39 to −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 following exacerbations and is as responsive to pulmonary rehabilitation as more complex COPD health status measures.

Figures in this Article

COPD health status measurements, such as the St. George Respiratory Questionnaire (SGRQ)1 and Chronic Respiratory Questionnaire (CRQ),2 provide complementary information to that obtained from spirometry. Although they have an established place in clinical trials, they have not been incorporated into routine clinical assessment. One factor may be their length and complexity. The COPD Clinical Questionnaire (CCQ)3 is a shorter instrument that can be used in routine care, but its development 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 in patients within a routine clinical practice setting.5,6 Initial validation studies demonstrated evidence of good internal validity and a strong correlation (r = 0.80) with SGRQ-C score in stable patients.5 The studies described here were designed to test the responsiveness of the CAT to changes in COPD health status under two conditions commonly seen in clinical practice: recovery from an exacerbation and response to pulmonary rehabilitation (PR).

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 rehabilitation; 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 defined 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 defined as the requirement for oral corticosteroids and/or antibiotics in response to increased symptoms for ≥ 2 days, with or without hospitalization. In addition, 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 Briefly, it consists of eight items scored from 0 (best) to 5 (worst) relating to coughing, mucus production, chest tightness, capacity for exercise and activities, confidence, 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 modified Medical Research Council (mMRC) dyspnea scale.8 They also completed the SGRQ-C,9 a shortened version of the SGRQ specific for COPD. SGRQ-C scores are directly comparable 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 “completely resolved.” Responders were defined as having a global rating of change in COPD since last visit of “better,” “much better,” or “completely resolved.” Nonresponders were defined 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; completed the CAT, mMRC dyspnea scale, SGRQ-C, and CRQ-Self Administered Standardized (CRQ-SAS) forms10; and performed a 6-min walk distance (6MWD) test.11 The Borg scale for breathlessness12,13 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 significance 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) (defined 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 ρ and Pearson r as appropriate. Group comparisons were tested using analysis of variance (ANOVA) or t tests.

Study Population

Demographic and clinical characteristics and maintenance 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 FEV1 and mMRC dyspnea scores were similar across the two studies.

Table Graphic Jump Location
Table 1 —Demographic and Clinical Characteristics of Patients

Data given as No. (%) unless otherwise indicated. 6MWD = 6-min walk distance; GOLD = Global Initiative for Chronic Obstructive Lung Disease; ICS = inhaled corticosteroid; LABA = long-acting β2 agonist; LAMA = long-acting antimuscarinic agent; LTOT = long-term oxygen therapy; mMRC = modified Medical Research Council; n/a = not applicable; nr = not reported; OCS = oral corticosteroid; RPE = rating of perceived exertion; SABA = short-acting β2 agonist; SAMA = 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.

Study 1 (Exacerbation)

There was a strong correlation between CAT score and SGRQ score at baseline (r = 0.75, P < .0001), and the correlation was similarly strong on day 14 (r = 0.73, P < .0001). Over 14 days, the mean CAT score improved significantly (mean change −1.4, P = .03), whereas no significant improvement was observed overall in SGRQ score (Table 2). There was a significant correlation between patient-rated global response and change in CAT score (ρ = −0.35, P = .004). In the patient-judged “responders” (n = 33), the mean change in CAT score was −2.8 ± 4.6 units. In the nonresponders (n = 32), the mean change was 0.0 ± 5.6 units; the difference between these two change scores was significant (P = .03) (Fig 1). A minimal 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).

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

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

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

There was a significant correlation between the global ratings of change assessed by patients and clinicians (ρ = 0.51, P < .0001). The pattern of change in CAT scores in patients defined by clinicians as responders (n = 34) or nonresponders (n = 31) was similar: the mean change was −2.6 ± 4.4 units in clinician-defined responders and −0.2 ± 5.9 units in clinician-defined nonresponders; the difference between the two change scores was not significant P = .08 (Fig 1). There was a significant correlation between clinician-rated global response and change in CAT score (ρ = −0.34, P = .006).

The correlation between change in CAT score and change in SGRQ score was not statistically significant (r = 0.24, P = .06), but the SGRQ change was different between patient-judged responders and nonresponders: −2.1 ± 7.3 units vs 2.8 ± 9.1 units; P = .022. In comparative terms, the change in CAT score in the patient-judged responders was 7.0% of the scaling 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 significant (Table 3). There was no significant correlation with FEV1 expressed as % predicted.

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

CRQ-SAS = 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.

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

CAT scores improved between days 1 and 42, with a mean change of −2.2 ± 5.3 units (P = .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 function, and mastery domains of the CRQ-SAS, but not for the dyspnea domain, which did not change in this study.

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

Data are presented as mean ± SD unless otherwise noted. FEV1, SGRQ, and mMRC dyspnea scale were assessed at the first visit only; therefore, there are no data on changes in these parameters. See Table 1-3 legends for expansion of abbreviations.

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

Figure Jump LinkFigure 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 = −0.53, P < .0001). B, Correlation between change in CAT scores and change in fatigue domain scores of the CRQ-SAS (r = −0.63, P < .0001). C, Correlation between change in CAT scores and change in emotion domain scores of the CRQ-SAS (r = −0.39, P = .002). D, Correlation between change in CAT scores and change in mastery domain scores of the CRQ–SAS (r = −0.45, P = .0003). See Figure 1 and 2 legends for expansion of abbreviations.Grahic Jump Location
Table Graphic Jump Location
Table 5 —Correlations Between Change in CAT Scores and Change in Patient/Clinician Assessments Following Pulmonary Rehabilitation (Day 42, Study 2)

See Tables 1 and 3 for expansion of abbreviations.

This study has shown that the CAT is responsive to changes in COPD health status during recovery following 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 first 14 days of recovery from an exacerbation also distinguished between clinical responders and nonresponders, when response was defined 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 further evaluation and/or treatment change. In patients who were judged, either by themselves or their clinician, 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 exercise 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 instrument that could be used routinely to evaluate the 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 first 14 days following an exacerbation clearly exceeded the provisional estimate 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.

This study further extends evidence for the convergent 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.

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 findings that warrant discussion. First, the correlation between change in CAT and change in SGRQ score following exacerbation recovery was weak. This is unsurprising, since the mean and range of changes in both scores were small, which makes detection of a significant correlation between changes in score very difficult without very large sample sizes. The weak correlation of the baseline CAT score with FEV1 % 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 recently16; 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 rehabilitation and is responsive to recovery from an exacerbation. The robust methods used in its development 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/languages, provided a properly translated version is used.

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

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 final version of the manuscript.

Ms Harding: contributed to developing the study protocol, interpreted study data, conducted statistical analysis, contributed to and reviewed all drafts of the manuscript, and approved the final version of the manuscript.

Dr Wiklund: contributed to developing the study protocol, interpreted study data, developed the first draft of the manuscript, contributed to and reviewed all drafts of the manuscript, and approved the final version of the manuscript.

Ms Berry: contributed to developing the study protocol, interpreted study data, contributed to and reviewed all drafts of the manuscript, and approved the final version of the manuscript.

Ms Tabberer: contributed to developing the study protocol, interpreted study data, developed the first draft of the manuscript, contributed to and reviewed all drafts of the manuscript, and approved the final 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 final version of the manuscript.

Dr Leidy: contributed to developing the study protocol, interpreted study data, developed the first draft of the manuscript, contributed to and reviewed all drafts of the manuscript, and approved the final version of the manuscript.

Financial/nonfinancial disclosures: The authors have reported to CHEST the following conflicts 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 consulting and other research services to pharmaceutical, device, government, and nongovernment organizations. In this salaried position, they work with a variety of companies and organizations. They received no payment or honoraria directly from these organizations for services rendered and are expressly prohibited 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 currently and employee of GlaxoSmithKline. Ms Tabberer has been directly employed or provided consultancy services to the pharmaceutical industry for 10 years and is currently and employee of GlaxoSmithKline.

Role of sponsors: GlaxoSmithKline did not place any restrictions 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 development of draft outline, development of manuscript first draft, editorial suggestions to draft versions of this paper, assembling tables and figures, 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 associated 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.

6MWD

6-min walk distance

ANOVA

analysis of variance

CAT

COPD Assessment Test

CRQ-SAS

Chronic Respiratory Questionnaire—Self-Administered Standardized

ES

effect size

GOLD

Global Initiative for Chronic Obstructive Lung Disease

MCID

minimal clinically important difference

mMRC

modified Medical Research Council

PR

pulmonary rehabilitation

RPE

Borg rating of perceived exertion

SGRQ-C

St. George Respiratory Questionnaire for COPD

Jones PW, Quirk FH, Baveystock CM. The St George’s Respiratory Questionnaire. Respir Med. 1991;85(suppl B):25-31. [PubMed] [CrossRef]
 
Guyatt GH, Berman LB, Townsend M, Pugsley SO, Chambers LW. A measure of quality of life for clinical trials in chronic lung disease. Thorax. 1987;42(10):773-778.
 
van der Molen T, Willemse BW, Schokker S, ten Hacken NH, Postma DS, Juniper EF. Development, validity and responsiveness of the Clinical COPD Questionnaire. Health Qual Life Outcomes. 2003;1:13.
 
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.
 
Jones PW, Harding G, Berry P, Wiklund I, Chen WH, Kline Leidy N. Development and first validation of the COPD Assessment Test. Eur Respir J. 2009;34(3):648-654.
 
Jones P, Harding G, Wiklund I, Berry P, Leidy N. Improving the process and outcome of care in COPD: development of a standardised assessment tool. Prim Care Respir J. 2009;18(3):208-215.
 
GOLD executive committeeGOLD executive committee. Global strategy for diagnosis, management, and prevention of COPD. GOLD website.http://www.goldcopd.org. Updated 2009. Accessed July 1, 2010.
 
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.
 
Meguro M, Barley EA, Spencer S, Jones PW. Development and validation of an improved, COPD-specific version of the St. George Respiratory Questionnaire. Chest. 2007;132(2):456-463.
 
Schünemann HJ, Goldstein R, Mador MJ, et al. A randomised trial to evaluate the self-administered standardised chronic respiratory questionnaire. Eur Respir J. 2005;25(1):31-40.
 
Enright PL. The six-minute walk test. Respir Care. 2003;48(8):783-785.
 
Borg GA. Psychophysical bases of perceived exertion. Med Sci Sports Exerc. 1982;14(5):377-381.
 
Martinez JA, Straccia L, Sobrani E, Silva GA, Vianna EO, Filho JT. Dyspnea scales in the assessment of illiterate patients with chronic obstructive pulmonary disease. Am J Med Sci. 2000;320(4):240-243.
 
Borg G. Ratings of perceived exertion and heart rates during short-term cycle exercise and their use in a new cycling strength test. Int J Sports Med. 1982;3(3):153-158.
 
Borg G. Psychophysical scaling with applications in physical work and the perception of exertion. Scand J Work Environ Health. 1990;16(suppl 1):55-58.
 
Dodd JW, Hogg L, Nolan J, et al. The COPD assessment test (CAT): response to pulmonary rehabilitation. A multicentre, prospective study. Thorax. 2011;66(5):425-429.
 
Spencer S, Jones PW GLOBE Study Group GLOBE Study Group. Time course of recovery of health status following an infective exacerbation of chronic bronchitis. Thorax. 2003;58(7):589-593.
 

Figures

Figure Jump LinkFigure 1. Study 1 (exacerbation): box plots showing change in CAT score on day 14 according to response/nonresponse to treatment of exacerbation, based on ratings of COPD change by patient and clinician. Patient responders: n = 33; nonresponders: n = 32, difference in mean change = 2.75, P = .03 (t test). Clinician responders: n = 34; nonresponders: n = 31, difference in mean change = 2.4, P = .08 (t test). CAT scaling range 0-40, higher score indicates poorer health. CAT = COPD Assessment Test.Grahic Jump Location
Figure Jump LinkFigure 2. Study 2 (pulmonary rehabilitation): scatter plot of baseline Pearson correlations between CAT score and the individual domains of CRQ-SAS. All significant at P < .0001. A, Correlation between CAT score and dyspnea domain of the CRQ-SAS (r = −0.65). B, Correlation between CAT score and fatigue domain of the CRQ-SAS (r = −0.62). C, Correlation between CAT score and emotion domain of the CRQ-SAS (r = −0.54). D, Correlation between CAT score and mastery domain of the CRQ-SAS (r = −0.69). CRQ-SAS = Chronic Respiratory Questionnaire—Self-Administered Standardized. See Figure 1 legend for expansion of other abbreviation.Grahic Jump Location
Figure Jump LinkFigure 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 = −0.53, P < .0001). B, Correlation between change in CAT scores and change in fatigue domain scores of the CRQ-SAS (r = −0.63, P < .0001). C, Correlation between change in CAT scores and change in emotion domain scores of the CRQ-SAS (r = −0.39, P = .002). D, Correlation between change in CAT scores and change in mastery domain scores of the CRQ–SAS (r = −0.45, P = .0003). See Figure 1 and 2 legends for expansion of abbreviations.Grahic Jump Location

Tables

Table Graphic Jump Location
Table 1 —Demographic and Clinical Characteristics of Patients

Data given as No. (%) unless otherwise indicated. 6MWD = 6-min walk distance; GOLD = Global Initiative for Chronic Obstructive Lung Disease; ICS = inhaled corticosteroid; LABA = long-acting β2 agonist; LAMA = long-acting antimuscarinic agent; LTOT = long-term oxygen therapy; mMRC = modified Medical Research Council; n/a = not applicable; nr = not reported; OCS = oral corticosteroid; RPE = rating of perceived exertion; SABA = short-acting β2 agonist; SAMA = 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.

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

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

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

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

Data are presented as mean ± SD unless otherwise noted. FEV1, SGRQ, and mMRC dyspnea scale were assessed at the first visit only; therefore, there are no data on changes in these parameters. See Table 1-3 legends for expansion of abbreviations.

Table Graphic Jump Location
Table 5 —Correlations Between Change in CAT Scores and Change in Patient/Clinician Assessments Following Pulmonary Rehabilitation (Day 42, Study 2)

See Tables 1 and 3 for expansion of abbreviations.

References

Jones PW, Quirk FH, Baveystock CM. The St George’s Respiratory Questionnaire. Respir Med. 1991;85(suppl B):25-31. [PubMed] [CrossRef]
 
Guyatt GH, Berman LB, Townsend M, Pugsley SO, Chambers LW. A measure of quality of life for clinical trials in chronic lung disease. Thorax. 1987;42(10):773-778.
 
van der Molen T, Willemse BW, Schokker S, ten Hacken NH, Postma DS, Juniper EF. Development, validity and responsiveness of the Clinical COPD Questionnaire. Health Qual Life Outcomes. 2003;1:13.
 
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.
 
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