Course of COPD assessment test (CAT) and clinical COPD

RES E AR C H Open Access

Course of COPD assessment test (CAT) and

clinical COPD questionnaire (CCQ) scores during

recovery from exacerbations of chronic

obstructive pulmonary disease

Marc Miravitlles

, Patricia García-Sidro

, Alonso Fernández-Nistal

, María Jesús Buendía

María José Espinosa de los Monteros

and Jesús Molina

Abstract

Introduction: COPD exacerbations have a negative impact on lung function, decrease quality of life (QoL) and

increase the risk of death. The objective of this study was to assess the course of health status after an outpatient

or inpatient exacerbation in patients with COPD.

Methods: This is an epidemiological, prospective, multicentre study that was conducted in 79 hospitals and

primary care centres in Spain. Four hundred seventy-six COPD patients completed COPD assessment test (CAT) and

Clinical COPD Questionnaire (CCQ) questionnaires during the 24 hours after presenting at hospital or primary care

centres with symptoms of an exacerbation, and also at weeks 4–6. The scores from the CAT and CCQ were

evaluated and compared at baseline and after recovery from the exacerbation.

Results: A total of 164 outpatients (33.7%) and 322 inpatients (66.3%) were included in the study. The majority

were men (88.2%), the mean age was 69.4 years (SD = 9.5) and the mean FEV1 (%) was 47.7% (17 .4%). During the

exacerbation, patients presented high scores in the CAT: [mean: 22.0 (SD = 7.0)] and the CCQ: [mean: 4.4 (SD = 1.2)].

After recovery there was a significant reduction in the scores of both questionnaires [CAT: mean: -9.9 (SD = 5.1) and

CCQ: mean: -3.1 (SD = 1.1)]. Both questionnaires showed a strong correlation during and after the exacerbation and

the best predictor of the magnitude of improvement in the scores was the severity of each score at onset.

Conclusions: Due to their good correlation, CAT and CCQ can be useful tools to measure health status during an

exacerbation and to evaluate recovery. However, new studies are necessary in order to identify which factors are

influencing the course of the recovery of health status after a COPD exacerbation.

Keywords: COPD, Health status, CAT, CCQ, Exacerbations

Introduction

Chronic Obstructive Pulmonary Disease (COPD) is a

major cause of death in industrialized countries. The

mortality rate of this disease is increasing and it is likely

to become the third leading cause of death worldwide in

2020 [1,2]. COPD is often aggravated by acute periods of

increased symptoms called exacerbations. These are the

most common reason for doctor’s visits, emergency de-

partment visits, hospital admissions and deaths [3].

In addition, numerous studies have shown that exacerba-

tions generate a large impact on health systems [3,4]. For

example, they cause 10-12% of primary care visits, 1-2% of

emergency room visits and 10% of hospitalizations in

Spain [4]. This is why, from an economic standpoint, these

data are of particular relevance since 44% of the annual

cost per patient involving COPD is due to hospital admis-

sions, exacerbations being the most frequent cause [5].

Among many other aspects, exacerbations are a ssoci-

ated to a deterioration in the patients’ quality of life [6].

* Correspondence: mmiravitlles @vhebron.net

Pneumology Department, Hospital Universitari Vall d'Hebron, Ciber de

Enfermedades Respiratorias (CIBERS), Barcelona, Spain

Full list of author information is available at the end of the article

Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and

reproduction in any medium, provided the original work is properly cited.

Miravitlles et al. Health and Quality of Life Outcomes 2013, 11:147

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However, studies that have focused on determining the

evolution of a patient after suffering an exacerbation are

mainly based on investigating functional [7,8] or inflam-

matory changes [9-11].

Certain generic quality-of-life questionnaires such as the

EuroQol Five-Dimensional Questionnaire (EQ-5D) [12],

or respiratory–specific questionnaires such as the St.

George’s Respiratory Questionnaire (SGRQ) [13], may be

useful to assess the recovery of patients who have suffered

an exacerbation. However, the usefulness of the most

widely used short questionnaires, the COPD Assessment

Test (CAT) [14] and the Clinical COPD Questionnaire

(CCQ) [15] to assess the course of moderate or severe ex-

acerbations has not been investigated adequately. These

two questionnaires have the great advantage of simplicity

for the patient, both having a very good correlation with

the SGRQ [14-16], considered the gold standard of spe-

cific health-related quality-of- life (HRQoL) questionnaires

for COPD.

In this work we present the results of the course of CAT

and CCQ scores during the recovery of an acute exacerba-

tion of COPD and the factors associated to the changes in

scores of patients recovering from these episodes, as well as

the comparison and correlation between both instruments.

Method

Study design

The ECO study (Exacerbations and quality of life in

COPD) was an observational, multicentre, prospective

study aimed at evaluating the predictive value of different

HRQoL questionnaires in the long-term course of patients

measured as time to the next exacerbation or death. In

order for the study to be feasible, we selected a population

of patients after recovery from an exacerbation, because

these subjects are more likely to suffer a second episode

during follow-up [17]. Patients were recruited upon pres-

entation at the hospital or at primary care offices with

symptoms of an exacerbation. Those who met inclusion

and exclusion criteria were informed about the study and

were asked to sign an informed consent document. The

physicians in charge collected information upon presenta-

tion or during the first 24 hours after admission. This in-

formation included demographic data, as well as data

related to smoking, medical history and comorbidities.

The cardiovascular risk was assessed according to BMI,

gender and waist circumference [18]. Patients were asked

to fill in COPD assessment test (CAT) and Clinical COPD

Questionnaire (CCQ) quality-of-life questionnaires in

their validated versions in Spanish.

The patients were evaluated again after 4 to 6 weeks

from the initial visit, at which point they filled out both

questionnaires once more. For the study, only those pa-

tients who recovered from the exacerbation during that

time frame were followed up for time to next exacerbation

or for death and they comprise the population of this ana-

lysis. The investigator had to verify clinical recovery; in

addition, patients had to answer “somewhat better” or

“much better” to a question about their health status: “In

relation to the previous visit, how are you?” using a 5-

point Likert scale with the following response options:

“Much worse, worse, same, better, much better. ”Further-

more, the CAT score must have improved by at least 5

units to consider that the patient had recovered from the

exacerbation [19].

Moderate COPD exacerbations were defined as a sud-

den increase in respiratory symptoms that required am-

bulatory treatment with systemic corticosteroids and/or

antibiotics, and exacerbations were considered severe

when the patient required hospitalization.

The study was approved by the ethics committee of

the Hospital Clinic (Barcelona , Spain. Reference num-

ber 2012/5918) and all participants provide d a w ritten

informed consent.

Population

Patients of both genders, aged 40 years or older, were

recruited in the study if they met the following inclusion

criteria: a) COPD demonstrated by spirometry performed

in stable state not more than 12 months before being

recruited in the study with a post-bronchodilator ratio of

FEV1/FVC < 0.7; b) smoker or former smoker of at least

10 pack-years; c) exacerbation defined as an increase in re-

spiratory symptoms that requires treatment with systemic

corticosteroids, antibiotics or both, and/or hospitalisation.

On the other hand, the exclusion criteria in the study

were: (i) patients with another chronic respiratory dis -

ease (e.g. bronc hia l asth ma, cystic fibrosi s, severe bron-

chiectasis , cancer, restrictive lung disease, etc.), (ii)

patients with a COPD exacerbation due to other causes

such as pneumonia , pneumothorax and de compe nsated

congestive heart failure, (iii) patients requiring inva sive

or non-invasive me chanical ventilation (iv) patient s

who, in the opinion of the investigator, did not retain

sufficient cognitive capacity, prese nting sensory or psy-

chiatric disability or language barriers that prevent or

hinder a normal conduction of the study , (v) patient s

participating in another study or clinical trial.

Measurements

The CAT consists of 8 items with scores ranging from 0

to 5 (0 = no impairment). An overall score is calculated

by adding the score from each item with total scores

ranging from 0 to 40, higher scores indicating a more se-

vere health status impairment or a poorer control of

COPD [16]. The CAT’s minimal clinical important dif-

ference (MCID) is not yet established and has been esti-

mated at 3.76 points [20]. The CCQ has three domains:

symptoms (4 items), functional status (4 items) and

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mental state (2 items), graded on a 7-point Likert scale

from 0 to 6 (0 = no impairment) [14]. The MCID has

been established at 0.41 points [21].

For the collection of information, a web-based form

(e-CRF) h as been designed specifically for this study.

Statistical analysis

In order describe the qualitative variables, absolute fre-

quencies and percentages were used; furthermore, for or-

dinal qualitative variables, cumulative frequencies and

percentages were used. The description of quantitative

variables was performed using the mean, standard devi-

ation (SD), median and quartiles. A comparison of qualita-

tive variables between two or more groups was performed

using the chi-square test and/or Fisher’s exact test. A com-

parison of quantitative variables between two groups was

performed using the Mann–Whitney U test or Student’s

t test, depending on the distribution of the data. A com-

parison of quantitative variables between three or more

groups was carried out using the Kruskall Wallis test or

ANOVA, depending on the distribution of the data. The

results of the analysis were adjusted by the techniques of

Oldham and Blomqvist. The correlation between quantita-

tive variables was performed using the Pearson correlation

coefficient; a correlation was considered good when the R

coefficient was higher than 0.7 and acceptable between 0.5

and 0.7.

We developed two regression models to determine the

factors that could best explain the change in score in each

of the questionnaires from the time of exacerbation until

recovery. Due to the non-normal nature of the variable

obtained for change in scores (recovery-exacerbation) for

CAT, it was decided to analyse this variable as categorical

by means of logistic regression analysis, divided into

tertiles of change: improvement of 5–6 points; improve-

ment of 7–12 points and improvement of more than 12

points. A linear regression analysis model for change in

the CCQ was developed taking into account the variable

as quantitative. Univariate analyses were carried out with-

out considering an intercept in the model, since each

intercept would vary depending on the type of each vari-

able (e.g., there is no estimate of a mean population prob-

ability of intensity change in the CAT, but all the

variability depends on the value of the dependent vari-

able). The multivariate model, however, in addition to

adjusting for the variables of the model, includes an inter-

cept. For the analysis we used the SAS Enterprise Guide

4.3. (SAS v.9.2)

Results

Patient population

A total of 675 patients were recruited in the study. Of

these, 45 were lost to follow-up, 39 did not meet inclu-

sion or exclusion criteria, 28 did not recover from the

exacerbation by 4 to 6 weeks and 77 were excluded due

to insufficient information for analysis, leaving 486

(72%) eligible patients. The demographic characteristics

of the patients are show n in Table 1. One hundred sixty-

four (33.7%) were outpatients and 322 (66.3%) were in-

patients. The majority were men (88.2%), the mean age

was 69.4 years (SD = 9.5) and the mean FEV1 (%) was

47.7% (17.4%). Compared with outpatients, inpatients

had a lower BMI, a longer smoking history and a lower

cardiovascular risk. Regarding COPD, these patie nts had

a longer history of the disease, as well as a greater num-

ber of exacerbations reported in the previous year and

more se vere lung function impairment as shown by

spirometry.

Changes in health status

At the time of exacerbation, the patients had high scores

on the CAT: [22.0 (SD = 7.0)], with differences between in-

patients [22.8 (SD = 7.0)], and outpatients [20.4 (SD =

6.9)]. After recovery, there was a significant reduction of

9.9 (SD = 5.1) points. Improvements were significant in

both inpatients and outpatients [8.9 (SD = 4.6) and 10.4

(SD = 5.3) respectively; p < 0.001 for both groups], (Table 2,

Figure 1).

Regarding the CCQ, the patients experienced a statis-

tically significant improvement in the global scale after

recovery, from a score of 4.4 point s (SD = 1.2) at the

time of exace rbation to 3.1 points (SD = 1.1) once stabi-

lized. This improvement occurred similarly in outpa-

tients and inpatient s [1.0 (SD = 0.9) and 1.4 (SD = 1.0),

respectively;p<0.001forbothgroups],andinallareas

of the questionnaire, but particularly in the symptoms score

(difference = −1.6 points (SD = 0.7); p < 0.001) (Table 2,

Figure 2).

Correlation between the questionnaires

Whatever the type of exacerbation (outpatient/inpatient),

there was a good correlation between the CA T scores and

the CCQ scores, both at exacerbation onset (R = 0.748;

p < 0.0001) (Figure 3), and once the patient had reco-

vered (R = 0.780; p < 0.001) (Figu re 4). Fu rthermore,

there wa s an acceptable correlation between the change

(exacerbation-recovery) scores in both questionnaires

(R = 0.594; p < 0.0001) (F igure 5).

Predictors of changes in health status

After performing the logistic regression analysis, it was

observed that the variation in the CAT scoring between

exacerbation onset and recovery wa s greatly dependent

on the score at exacerbation onset. Thus, there was a

greater improvement for patients who began with the

worse initial status [OR (95% CI): 0.84 (0.81 to 0.86),

p < 0.00 1]. In this model, the outcome variable (change in

CAT score) wa s categorised into 3 categories and the

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OR indicates the odds to move from each category to

the next. Nevertheless, the adjusted model can only ex-

plain 32.4% of the variance ( Table 3).

Regarding the CCQ, the resulting model explains

30.8% of the variability. The improvement in CCQ

scores at recovery from exacerbation is greater when:

there is a higher baseline CCQ score [β (95% CI): -0.46

(−0.52 to −0.40); p < 0.001], fewer total exacerbations in

the past year [β (95% CI): 0.04 (0.01 to 0.07); p = 0.007]

and the patient is not living with smokers [β (95% CI): -

0.25 (−0.44 to −0.06); p = 0.01] (Table 4).

Discussion

The results of the current study have demonstrated

there is a severe impairment in the health status of exac-

erbated patients, both in inpa tient and outpatient set-

tings. As expected, scores of both questionnaires were

significantly worse in admitted compared with ambula-

tory patients. The patients who recovered from the acute

episode showed a highly significant improvement in the

scores of the CAT and the CCQ. Furthermore, there was

a good correlation of the scores of both questionnaires

at exacerbation onset and at recovery. The best predictor

of the magnitude of the improvement in scores of both

questionnaires is the score of the given questionnaire at

exacerbation onset. These results suggest that both ques-

tionnaires can be used in a clinical setting to evaluate the

improvement in health status during and/or after the

treatment of a moderate or severe exacerbation of COPD.

The CAT questionnaire has shown to provide signifi-

cantly different scores in stable and exacerbated patients

in cross-sectional studies. Jones et al. [22], in a validation

study, reported a mean score of 17.2 points in stable

COPD patients compared with 21.3 in exacerbated COPD

patients. Agustí et al. [23] obtained a score of 22.4 points

in a group of COPD inpatients compared with 15.8 in

stable patients. Interestingly, we obtained an almost identi-

cal CAT score in our inpatients (22.8 points), which was

significantly reduced to only 12.4 after recovery from the

acute episode. This large improvement in CAT scores after

an admission is similar to the one reported by the previous

group of investigators in patients who claimed to feel

“much better” after recovery from the hospitalization (8.9

units) [13]. When analysing the data in the opposite

Table 1 Demographic and clinical characteristics

Variable Total Ambulatory Hospital p value

N = 486 N = 164 N = 322

Sex, male 432 (88.9) 138 (84.2) 294 (91.3) 0.022

Age, years 69.4 (9.5) 69.5 (9.1) 69.3 (9.7) 0.91

BMI, Kg/m2 27.8 (9.7) 29.4 (14.9) 26.9 (5.1) <0.001

Active smokers 139 (28.6) 49 (29.9) 90 (28) 0.65

Smoking habit, pack/years 54.5 (30.5) 48.9 (28.9) 57.3 (30.9) 0.004

Level of education

No school 117 (24.1) 22 (13.4) 95 (29.5) <0.001

Primary education 245 (50.4) 93 (56.7) 152 (47.2)

Secondary/higher education 124 (25.5) 49 (29.9) 75 (23.3)

Cardiovascular risk

None 123 (25.3) 28 (17.0) 95 (29.5) 0.009

Increased 128 (26.3) 45 (27.4) 83 (25.8)

High 115 (23.7) 39 (23.8) 76 (23.6)

Very high 120 (24.7) 52 (31.7) 68 (21.1)

Diabetes mellitus 127 (26.1) 41 (25.0) 86 (26.7) 0.68

Waist circumference, cm 99.2 (18.7) 101.3 (14.7) 98.1 (20.4) <0.001

Time walking per day, minutes 55.0 (26.0) 68.2 (32.3) 48.08 (24.2) <0.001

Time of COPD evolution, years 9.9 (8.3) 8.6 (7.4) 10.6 (8.6) 0.013

Number of exacerbations previous year 2.9 (2.7) 2.4 (1.9) 3.2 (2.9) 0.002

FVC, mL 2549.1 (795.9) 2930.9 (864.8) 2357.0 (683.0) <0.001

FVC, % 68.1 (17.5) 76.3 (16.1) 64.0 (16.7) <0.001

FEV1, mL 1312.9 (523.8) 1658.9 (534.9) 1138.8 (422.5) <0.001

FEV1, % 47.7 (17.4) 59.3 (16.2) 41.8 (14.9) <0.001

FEV1/FVC, % 51.4 (11.7) 56.9 (9.8) 48.7 (11.6) <0.001

Values are expressed as mean (standard deviation) or frequency (%).

Footnote: BMI Body Mass Index.

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direction (from stable state to exacerbation) MacKay et al.

[19] noted a change from 19.4 to 24.1 points in the CAT

score in a population of outpatients with COPD. This

change was smaller in magnitude to the one observed in

our study, but the health status impairment of those pa-

tients was more severe than that observed in our popula-

tion (CAT = 12.1 at recovery). Another difference is that

return to baseline in the aforementioned study was con-

sidered at 11 days, in contrast to 4 to 6 weeks in our study.

Previous studies using the SGRQ suggested that the health

status may require up to 12 weeks to full recovery [13].

Despite of these results, we have to take into consideration

the fact that CAT has not been validated for determining

the severity of an exacerbation. In fact, some subjects in-

cluded in the Mackay [19] study had a decline in the CAT

score when they suffered an exacerbation, while others

had no significant changes. Questionnaires designed spe-

cifically to assess the changes in health status during exac-

erbations such as the EXAcerbations of Chronic

Obstructive Pulmonary Disease Tool (EXACT) can be

more useful for quantifying the severity of these events

[24].

In addition, it must be noted that due to the design of

the study, we only considered those patients who recov-

ered from the exacerbation and one of the criteria for re-

covery was an improvement of at least 5 points in CAT

scores. Therefore, we cannot analyse the validity of the

questionnaires to identify patients who could fail in the

treatment of an exacerbation. However, only 28 patients

(4.2%) could not be recruited in the study because they

did not reach this thresh old at recovery.

p<0,001

Figure 1 Course of CAT scores following an outpatient or

inpatient exacerbation.

Figure 2 Course of CCQ scores following an outpatient or

inpatient exacerbation.

0123456

CAT Total

CCQ Total

Exacerbation

Hospitalized

Ambulatory

Figure 3 Correlations between CAT and CCQ scores at onset of

exacerbation. Correlation of scores in the global population R =

0.748 (p < 0.0001), in outpatient exacerbations R = 0.788 (p < 0.0001)

and in inpatient exacerbations R = 0.723 (p < 0.0001).

Table 2 Course of health status, CAT and CCQ test scores

Questionnaire Exacerbation Recovery Change (R-E) P value

CAT total

Total 22.0 (7.0) 12.1 (5.9) −9.9 (5.1) <0.001

Outpatient 20.4 (6.9) 11.5 (5.8) −8.9 (4.6) <0.001

Inpatient 22.8 (7.0) 12.4 (6.0) −10.4 (5.3) <0.001

CCQ total

Total 4.4 (1.2) 3.1 (1.1) −1.3 (0.9) <0.001

Outpatient 3.8 (1.2) 2.8 (1.0) −1.0 (0.9) <0.001

Inpatient 4.6 (1.1) 3.2 (1.1) −1.4 (1.0) <0.001

CCQ; symptoms

Total 4.7 (1.3) 3.1 (1.1) −1.6 (0.7) <0.001

Outpatient 4.4 (1.3) 3.1 (1.1) −1.3 (0.9) <0.001

Inpatient 4.9 (1.2) 3.1 (1.1) −1.8 (1.0) <0.001

CCQ: functional

Total 4.1 (1.4) 3.1 (1.3) −1.0 (1.2) <0.001

Outpatient 3.4 (1.3) 2.6 (1.1) −0.8 (0.5) <0.001

Inpatient 4.5 (1.3) 3.3 (1.3) −1.2 (0.7) <0.001

CCQ: mental

Total 4.1 (1.5) 2.9 (1.4) −1.2 (1.1) <0.001

Outpatient 3.6 (1.5) 2.7 (1.3) −0.9 (0.9) <0.001

Inpatient 4.4 (1.5) 3.1 (1.4) −1.3 (1.1) <0.001

Values are expressed as mean points (standard deviation).

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Regarding the CCQ, we noted a mean reduction of −1.3

points at recovery, which was even higher for the symp-

toms scale (−1.6 points) and clearly higher than the sug-

gested clinically significant minimum difference of 0.41

[20]. In a previous cross-sectional study on 3,935 COPD

patients in Spain, the mean value of CCQ was 2.5 and it

was significantly associated to the degree of dyspnoea, the

frequency of previous exacerbations and hospitalizations,

the severity of FEV1 impairment and a low level of educa-

tion and physical activity [25]. However, longitudinal data

of CCQ during recovery from exacerbations is limited. In

contrast, an improvement in total scores of around 0.50

points has been observed after quitting smoking (improve-

ment of 1.02 points in symptoms) [14,26]. The CCQ

scores have been used for monitoring patients to predict

treatment failure or the occurrence of an exacerbation.

Using weekly measurements, an impairment of 0.20 points

had a positive predictive value of 43.5% and a negative

predictive value of 90.8% for the onset of an exacerbation

in the next week [27]. Furthermore, a recent work in

which the patients were monitorised daily during an ex-

acerbation, showed that the absence of improvement in

CCQ symptoms score and impaired lung function were

independent predictors of treatment failure [28]. Concur-

rent with our results, the authors find the rate and pattern

of recovery very similar in outpatients and inpatients [28].

Similarly to CAT, the best predictor of a large im-

provement in CCQ score after re cove ry wa s a worse

score at exacerbation onset. A regression to the mean

effect cannot be ruled out; however, for the improve-

ment in CCQ scores other variables showed a signifi-

cant and independent association with the magnitude of

change. The patient s who experience d fewer exacerba -

tions in the past had a higher improvement in CCQ

scores, as did those who lived with smokers. The rela-

tionship between repeated exacerbations and impair-

ment in HRQoL has been noted in numerous studies

[6,29], and wa s seen consistently with our results; a pre-

vious study demonstrated that patients who suffered re-

peated exacerbations did not revert to the baseline

values of he alth status after an exacerba tion [13]. The

relationship between a higher improvement in CCQ

scores and living with smokers is difficult to account for

and might be related with worse scores at onset be cause

more se vere symptoms as sociat ed to second hand

smoke, but this hypothesis should be tested adequately.

However, only a small part of the variance has been

explained by the variables included in the regression

models. Other factors not addressed in our study may

influence the re covery of these patient s. For instance,

Papaioannou et al. [30] observed that depressive symp-

toms had a negative effect on CAT improvement during

recovery from an exacerbation.

The difference between the predictors of recovery found

for CAT and CCQ can be explained in part by the different

types of analysis; however, there are also some differences

between them. CA T is a one-dimensional questionnaire, in

turn, CCQ has different domains that correlate better with

the corresponding SGRQ domains [20]. Furthermore,

CCQ has been validated to be used at the level of individ-

ual patients [31].

More interesting and unique in our results was the rela-

tionship between the scores of both questionnaires. We

have demonstrated a good correlation of the scores of

CAT and CCQ at exacerbation onset and at recovery and

also an acceptable correlation of the changes in scores ob-

served in both questionnaires after recovery. These results

suggest that both are measuring the same effects and that

both can be used reliably in this context. To the best of

our knowledge, this is the first study to compare the per-

formance of both questionnaires during the recovery of

0123456

CAT Total

CCQ Total

Recovery

Hospitalized

Ambulatory

Figure 4 Correlations between CAT and CCQ scores after

recovery from the exacerbation. Correlation of scores in the

global population R = 0.780 (p < 0.0001), in outpatient exacerbations

R = 0.827 (p < 0.0001) and in inpatient exacerbations

R = 0.760 (p < 0.0001).

-30

-25

-20

-15

-10

-5

-6 -5 -4 -3 -2 -1 0 1 2 3

Change in CAT

Chan

e in CCQ

Correlations of change in CAT and CCQ scores)

Hospitalized

Ambulatory

Figure 5 Correlations between CAT and CCQ changes in scores

between exacerbation and recovery. Correlation of scores in the

global population R = 0.594 (p < 0.001), in outpatient exacerbations R =

0.561 (p < 0.0001) and in inpatient exacerbations R = 0.591 (p < 0.0001).

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outpatient and inpatient exacerbations. The CAT and the

CCQ have also demonstrated a good correlation in

stable COPD; Tsiglian ni et al [20] obser ved a rho = 0.64

between both scores in a group of 90 stable COPD pa-

tients over three repeated measurements. More over, in

a study of severe COPD patients referred for rehabilita-

tion, a correlation of r = 0.77 was shown between the

CAT and the CCQ [32]. These values are similar to

those obtained in our patient population ranging from

r = 0.72 to r = 0.82 for correlations betwe en both ques-

tionnaires e ither at onse t or at re covery from the ex-

acerbation. These result s support the use of either

questionnaire in the clinical assessment of patients with

COPD, a s suggested in re cent guidelines [33,34].

Our study ha s several limitations , we have only

analysed the patients that recovered from an exacerba-

tion and therefore we cannot investigate a different

course of scores ac cording to clinical outcomes. Our re-

sults describe only the course of improvement of health

status after an exacerbation. Another limitation is the

use of a C AT cut-off value of 5 points for defining re-

covery from an exacerbation. Currently, the re is no

well-established MCID for CAT, which is why we also

used the investigator’s clinical judgement and a question

with a Likert scale for the patient to contribute t o the

definition of re covery.

One of the strengths of our study is its obser vational

design in a large sample of patients in different settings ,

which allows for the extrapolation of result s with a high

external validity.

In summary, our results have demonstrated a severe

impairment in the health status of COPD patient s at ex-

acerbation onsets, a s measured by CCQ and CAT

scores. Health status significantly improves during re-

covery. There is a strong correlation between the scores

of both questionnaires at onse t and at re covery and the

best predictor of the magnitude of improvement is the

severity of the score at onset. Both instrument s can be

used to monitor the course of recovery of outpatient or

inpatient COPD exacerbations.

Table 3 Study of univariate and multivariate association of change in CAT score from exacerbation to stable state,

categorized into three categories (5–6 points, 7–12 points, and over 12)

Variable Univariate Multivariate

OR 95% CI P OR 95% CI P

Type of exacerbation (inpatient vs. outpatient RC) 2.3 1.6 to 3.2 <0.001

Gender (men vs. women RC) 2.3 1.6 to 3.3 0.051

Waist circumference 0.994 0.992 to 0.996 <0.001

Smoking status (current vs. former smoker RC) 1.64 1.17 to 2.32 0.004

Exacerbations previous year 0.89 0.85 to 0.93 <0.001

FEV1 (%) 0.99 0.98 to 0.99 <0.001

CAT at inclusion 0.96 0.95 to 0.97 <0.001 0.84 0.81 to 0.86 <0.001

CCQ at inclusion 0.84 0.80 to 0.87 <0.001

Independent variables: waist circumference, exacerbations in the previous year, FEV1 (%) and CAT and CCQ at inclu sion were continuous variables. The strength

of the association is presented by the OR and 95% confidence interval obtained by logistic regression.

OR odds ratio, CI confidence interval, RC Reference category.

Table 4 Study of univariate and multivariate association of change in CCQ score from exacerbation to stable state

Variable Univariate Multivariate

B 95% CI P B 95% CI P

Type of exacerbation (inpatient vs. outpatient RC) −1.44 −1.56 to − 1.32 <0.001

Gender (men vs. women RC) −1.27 −1.38 to − 1.17 <0.001

BMI −0.004 −0.008 to −0.0002 <0.001

Smoking (current vs. former-smoker RC) 1.33 1.57 to 1.09 <0.001

Lives with smokers (yes vs. no RC) 1.44 1.12 to 1.75 <0.001 −0.25 −0.44 to −0.06 0.010

Exacerbations previous year −0.25 −0.28 to −0.22 <0.001 0.04 0.01 to 0.07 0.007

FEV1 (%) −0.023 −0.043 to 0.003 <0.001

CAT at inclusion −0.057 − 0.06 to −0.05 <0.001

CCQ at inclusion 0.84 0.80 to 0.87 <0.001 −0.46 −0.52 to −0.04 <0.001

The CCQ score change has been studied as a continuous variable and the strength of the association occurs through the beta coe fficients obtained by linear

regression. BMI, exacerbations previous year FEV1 (%) and CAT and CCQ at inclusion were continuous variables.

B Beta coefficient, CI confidence interval, RC Reference category.

Miravitlles et al. Health and Quality of Life Outcomes 2013, 11:147 Page 7 of 9

http://www.hqlo.com/content/11/1/147

Competing interests

Marc Miravitlles has received speaker fees from Boehringer Ingelheim, Pfizer,

AstraZeneca, Bayer Schering, Novartis, Talecris-Grifols, Takeda-Nycomed,

Merck, Sharp & Dohme and Novartis, and consulting fees from Boehringer

Ingelheim, Pfizer, GSK, AstraZeneca, Bayer Schering, Novartis, Almirall, Merck,

Sharp &Dohme, Talecris-Grifols and Takeda-Nycomed. Alonso Fernández is a

full time employee of Takeda. The rest of authors have no conflicts of

interest to disclose.

Authors’ contributions

MM, JM and AFN designed the study and directed the data analysis. MM

and AFN drafted the manuscript. PGS, M JB, MJEM, JM participated in data

collection and critical revisión of the data analysis. All authors read and

approved the final manuscript.

Acknowledgments

The study was sponsored by Takeda Farmacéutica España S.A. The authors

thank Dr. Jesús Aparicio (Medical Department, Takeda Farmacéutica España) for

his contribution to the design and execution of the study.

Investigators and study sites are listed below: David De La Rosa (Hospital Plató,

Barcelona), María Magdalena Medinas (Hospital Joan March, Mallorca), Juan Luis

Rodriguez Hermosa (Hospital Clínico San Carlos, Madrid), Luis Perez De Llano

(Hospital Universitario HULA, Lugo), Berta Avilés Huertas (Hospital de Palamós,

Girona), Bernardino Alcázar Navarrete (Hospital De Alta Resolución De Loja,

Granada), Silvia Molina Aguilera (Hospital De Campdevànol, Girona), Javier

Labayen (Hospital de Donostia, Guipuzcoa), Juan Pablo De Torres (Clínica

Universidad De Navarra), Ada Luz Andreu Rodriguez (Hospital Los Arcos Del Mar

Menor, Murcia), Montserrat Vendrell (Hospital Josep Trueta, Girona), Maria Jesus

Buendía Garcia (Hospital Infanta Leonor, Madrid), Maria Victoria Medina Cruz

(Hospital Doctor Negrín, Las Palmas de Gran Canaria), Valentin Cabriada Nuño

(Hospital de Cruces, Bizkaia), Maria Jesus Mena Rodriguez (Hospital La Mancha

Centro, Ciudad Real), José Calvo Bonachera (Hospital de Torrecardenas, Almeria),

Lourdes Lázaro Asegurado (Hospital General Yagüe, Burgos), Jose Manuel Cifrián

Martinez (Hospital Marqués De Valdecilla, Cantabria), Manuel Brufal (Hospital

Virgen De Los Lirios, Alicante), Xavier Vilà (Hospital De Mataró, Barcelona), Ana

Bustamante (Hospital de Sierrallana, Cantabria), Ana Pando Sandoval (Hospital

Universitario Central De Asturias), Salvador Díaz Lobato (Hospital Ramon y Cajal,

Madrid), María Carmen Fernández (Hospital Universitario Reina Sofía, Córdoba),

Felix Del Campo Matías (Hospital Rio Hortega, Valladolid), Graciliano Estrada

(Hospital De Segovia), Agustín Medina (Hospital de La Laguna, Tenerife), Marina

Blanco (C. Universitario A Coruña), Ernesto Centeno (Hospital San Eloy, Bizkaia),

Isaura Parente (Complexo Hospitalario De Ourense), Joan Serra (Hospital General

De Vic, Barcelona), Silvia Fernández Huerga (Hospital De León), Eva Balcells

(Hospital Del Mar, Barcelona), Beatriz Lara (Hospital Universitario Arnau de

Vilanova, Lleida), José Alcázar Ramírez (Clínica Quirón, Málaga), Sagrario

Mayoralas Alises (Hospital Moncloa, Madrid), Rosa Cordovilla Pérez (Hospital

Universitario Salamanca), Ángel Ortega (Hospital General Nuestra Señora Del

Prado, Toledo), Manuel Agustin Sojo (Hospital San Pedro De Alcantara, Cáceres),

Gustavo Villegas (Hospital Torrecardenas, Almería), Gerardo Pérez Chica (Hospital

Ciudad De Jaén), Mª Dolores Aicart Bort (CS Rafalafena, Castellón), Tertuliano

Amat Sotos (CS Acacias. Alicante), Maria Teresa Almela (CS Salvador Pau,

Valencia), Juan Luis Mendía (CS Ondarreta, Guipúzcoa), Isidro López (UAP

Begonte, Lugo), Javier Pérez (CS Calzada 2, Asturias), Maria Angélica Molina

(CS A Ponte, Ourense), Carmen Llorente (CS Villalba-Estación, Madrid), Luisa

Fernanda Sidro Bou (CS De La Vall D’Uixó, Castellón), Francisco Ponce (CS Petrer

I, Alicante), Carmen Vizuete (CAP Montclar, Barcelona), Carlos Ramirez (CS

Salvador Allende, Valencia), Enrique Mascarós (CS Fuente De San Luis, Valencia),

Luis García-Giralda (CS Murcia-Centro, Murcia), Rosario Timiraos (CS de

Culleredo, A Coruña), Jesus Méndez-Cabeza (CS Torrelodones, Madrid), Alvaro

Aguirre De Cárcer (CS La Ventilla, Madrid), Jose Maria Fernandez Rodriguez-

Lacin (CS Natahoyo, Asturias), Albert Brau Tarrida (CAP La Mina, Barcelona),

Tomas Soler López (C.S. Zona VII, Albacete), Javier Amiama (EAP Sodupe,

Bizkaia), José Paredes Saura (CAP Hostalric, Girona), Jose Ignacio Sánchez

(CS Fuente San Luis, Valencia), Ramon Cervera (CS Godella, Valencia), Vicente

Alfonso Corral (UGC Puerto Sur, Cádiz), Araceli Fernandez (CS Delicias Sur,

Zaragoza), Olga Vicente Lopez (CS Las Rozas, Madrid), Mario Bárcena Caamaño

(CS Nóvoa Santos, Ourense), Manuel Angel Gómez (CS La Alamedilla,

Salamanca), Miguel Florido Rodríguez (Consultorio De Playa De Arinaga, Las

Palmas de Gran Canaria), Montserrat Mas Pujol (EAP Chafarinas,

Barcelona), Xavier Flor (CAP Chafarinas, Barcelona), Javier Antón Ortega

(CS Repelega, Bizcaia).

Author details

Pneumology Department, Hospital Universitari Vall d'Hebron, Ciber de

Enfermedades Respiratorias (CIBERS), Barcelona, Spain.

Pneumology Unit,

Hospital De La Plana, Villarreal, Spain.

Medical Department, Takeda

Farmacéutica España S.A, Madrid, Spain.

Pneumology Department, Hospital

Universitario Infanta Leonor, Madrid, Spain.

Pneumology Department,

Hospital Universitario Virgen de la Salud, Toledo, Spain.

Centro de Salud

“Francia”, Fuenlabrada, Madrid, Spain.

Received: 30 April 2013 Accepted: 29 August 2013

Published: 29 August 2013

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doi:10.1186/1477-7525-11-147

Cite this article as: Miravitlles et al.: Course of COPD assessment test

(CAT) and clinical COPD questionnaire (CCQ) scores during recovery

from exacerbations of chronic obstructive pulmonary disease. Health

and Quality of Life Outcomes 2013 11:14 7.

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