Development and validation of the living with chronic obstructivepulmonary disease questionnaire

Stephen P. McKenna • David M. Meads • Lynda C. Doward •

James Twiss • Robin Pokrzywinski • Dennis Revicki •

Cameron J. Hunter • G. Alastair Glendenning

Accepted: 10 January 2011 / Published online: 11 February 2011

� Springer Science+Business Media B.V. 2011

Abstract

Purpose Available patient-reported outcome (PRO) mea-

sures for chronic obstructive pulmonary disease (COPD)

focus primarily on impairment (symptoms) and activities

(functioning). The purpose of the study was to develop a

patient-based PRO measure for COPD that captures the

overall everyday impact of living with COPD from the

patient’s perspective.

Methods LCOPD items (Living with COPD Question-

naire) were generated from qualitative interviews in the UK

and focus groups in the USA. The draft measure was tested

for face and content validity in both countries. Item reduction

and testing for reproducibility and construct validity was

conducted via Rasch and traditional psychometric analyses.

Results The draft LCOPD was found to be relevant and

acceptable to patients in the UK (N = 19) and US (N = 16).

Application of Rasch analysis to data collected in validation

studies (n = 162 in the UK and 145 in US) identified a

22-item scale that measured a single construct in both

countries. Psychometric analyses indicated that this version

was internally consistent and reproducible. Scores on the

measure were related as expected to clinician ratings of

disease severity and patient ratings of COPD severity and

general health.

Conclusions The LCOPD is a new measure examining

the everyday impact of living with COPD. It demonstrates

good scaling properties and may prove valuable in under-

standing treatment benefits.

Keywords Chronic obstructive pulmonary disease �LCOPD � Quality of life � Patient-reported outcomes �Questionnaire

Abbreviations

DIF Differential item functioning

LCOPD Living with COPD Questionnaire

PRO Patient-reported outcome

QoL Quality of life

SGRQ St. George’s Respiratory Questionnaire

Background

Data from National Health and Nutrition Examination

Survey (III) estimated that about 24 million US adults have

evidence of impaired lung function, of whom only 10

million are physician-diagnosed as having COPD [1].

During 2000, COPD was responsible for 8 million physi-

cian office and hospital outpatient visits, 1.5 million

emergency department visits, 726,000 hospitalizations, and

119,000 deaths in the USA [2]. Recently, the BOLD study

estimated the global prevalence of stage II or higher COPD

to be 10.1% [3]. The progression of COPD imposes pro-

found limitation on activities of daily living and gives rise

to symptoms of anxiety and depression. The distressing

S. P. McKenna (&) � D. M. Meads � L. C. Doward � J. Twiss

Galen Research, Manchester, UK

e-mail: smckenna@galen-research.com

R. Pokrzywinski � D. Revicki

Centre for Health Outcomes Research, United BioSource

Corporation, Bethesda, USA

C. J. Hunter

Peterborough District Hospital NHS Trust, Peterborough, UK

Present Address:C. J. Hunter

Royal Hobart Hospital, Tasmania, Australia

G. A. Glendenning

Novartis AG, Horsham, UK

123

Qual Life Res (2011) 20:1043–1052

DOI 10.1007/s11136-011-9850-6

symptoms of breathlessness and fatigue lead to a marked

reduction in health outcomes [4].

Until recently, clinical trials have focussed on clinical

assessments of outcome such as forced expiratory volume

and airway responsiveness. However, there is increasing

evidence that such clinical indicators do not capture fully

the patient’s experience [5–7]. In addition, patients may

experience an improvement in health status that is not

detected by clinical assessments [8, 9]. Given this, it is

important that patients’ heath status and quality of life

(QoL) are assessed in addition to clinical indicators when

evaluating treatment efficacy [10–12].

A comprehensive review of patient-completed health

status and QoL questionnaires available for use in COPD

studies revealed that a significant number of both generic

and disease-specific questionnaires have been employed.

However, the review indicated that most of these patient-

reported outcome measures focus on symptoms and func-

tioning. Where emotional and QoL issues were assessed in

these measures, it is by only a small proportion of the

items. There is scope for a measure capable of assessing

the overall impact of living with COPD on the patient.

Consequently, it was decided to develop a QoL measure

specific to COPD that would capture the overall impact of

the disease from the patient’s perspective. The measure

was required to be unidimensional, to have good psycho-

metric properties and to be suitable for use alongside

existing disease-specific scales that capture the symptom-

atic and functional impact of COPD.

Methods

Ethics approval at each stage of development of the

LCOPD was sought and gained in the UK and USA.

The needs-based model of QoL were employed for the

LCOPD [13]. This model asserts that QoL is dependent on

an individual’s ability to fulfil his or her fundamental needs

and that QoL is good when most needs are met and poor

when they are not.

Development of the LCOPD was undertaken in parallel

in the UK and USA and involved three stages: (1) item

generation, (2) testing for face and content validity and (3)

establishment of its psychometric properties. Stages 2 and

3 were also used for item reduction.

Item generation

Scale content was generated from qualitative, unstructured

interviews conducted with patients with COPD in the UK

and focus groups with patients in the USA. The intervie-

wees and focus group participants were encouraged to talk

at length about their experience of COPD and the impact of

the disease on all areas of their life. Audio recordings were

made of the interviews and focus group discussions. These

were transcribed, and each interview was subjected to

content analysis by at least two experienced qualitative

researchers to identify statements expressing the impact of

LCOPD on patient’s lives. As far as possible, the original

words of the interviewees were maintained in the items to

ensure that they were personal and would feel immediate to

future respondents. Items were included in the UK and US

LCOPD item pools if they were

• applicable to all potential respondents;

• expressed in the first person;

• unambiguous;

• short and simple, and

• reflected a single idea.

The two item pools were then compared, and items cov-

ering common issues were retained in the final item pool.

Cognitive debriefing interviews

The preliminary LCOPD was tested for face and content

validity by means of cognitive debriefing interviews con-

ducted with patients with COPD in both countries. These

face-to-face interviews also examined the practicality and

acceptability of the new questionnaire. Changes in wording

and format suggested by more than one respondent were

evaluated, and changes were made to the LCOPD where

appropriate.

Validation study

For item reduction and to determine the scaling properties,

reliability and construct validity of the LCOPD, larger

samples of patients were required in each country. Patients

were recruited from a district hospital and patient support

groups in the UK and through four US clinics. Patients were

included in the study if they were 18 years or older and had

been diagnosed by a physician as having COPD. Patients

were excluded if they were unable to read and respond to

questionnaires, if they could not provide informed consent or

if they had co-morbidity likely to influence their QoL sig-

nificantly (for example cardiac failure, persistent anaemia,

cancer). Patients were required to complete the LCOPD on

two occasions, 2 weeks apart. UK patients completed the

measure at home and US patients at visits to the clinic. Only a

subset of patients was asked to attend for a second visit in the

USA for the assessment of reproducibility. Patients also

completed demographic questions, questions on perceived

severity of COPD and general health and the St. George’s

Respiratory Questionnaire (SGRQ) [14].

Scaling and item reduction: The study data were sub-

jected to Rasch analysis [15] for final item reduction using

1044 Qual Life Res (2011) 20:1043–1052

123

the Rasch Unidimensional Measurement Model [16]. The

Rasch model assumes that the scale has the basic property

of unidimensionality, with all items reflecting a single

underlying construct—in this instance, the overall impact

of COPD on QoL. Each item and each person is placed

along the continuum or trait being captured, and the dis-

tance between these locations indicates the probability that

a person will endorse an item (for example ‘I have to pace

myself’) as true. The Rasch model is explained in detail

elsewhere (see for example [17]).

The overall fit of the data to the Rasch model was evalu-

ated by means of v2 fit statistics. Non-significant results

indicate that there is no significant deviation between the

observed data and what would be expected by the model.

Due to multiple testing, a significance level of 0.01 was used

to indicate fit to the model. Overall fit of the data is also

investigated by means of item and person residual statistics.

Where data fit the model, item and person fit residuals should

have means and standard deviations of approximately 0 and

1, respectively. Together, these findings indicate whether the

scale is unidimensional. Individual items were also assessed

to see whether they fit the Rasch model. Items were con-

sidered for removal if they showed misfit to the model

(P \ 0.01) or if they had excessive fit residuals ([2.5 or

\-2.5). Highly negative residuals indicate over-fit to the

model (i.e. the item does not add anything extra to the scale

and is duplicating other items). Highly positive residuals

indicate under-fit to the model (i.e. the item does not add

anything to the scale and perhaps violates unidimensionality).

Rasch analysis also allows the assessment of differential

item functioning (DIF) [18]—the extent to which responses to

individual items are affected by factors that are external to the

construct being assessed, such as age and gender. The person

separation index (PSI), or the extent to which the construct can

discriminate among respondents, was also assessed. The

minimum acceptable level for the PSI is 0.70. Finally, infor-

mation about the extent to which the items match the severity

of the respondents and the order of severity of the items was

gained by examining item maps plotting the items and

respondents visually on the same severity continuum. Items

found to be problematic in terms of fit to the model or DIF by

age or gender were considered for removal.

Reliability, reproducibility and construct validity

Following identification of the final version of the LCOPD,

the following traditional psychometric properties of the

scale were assessed:

• Internal consistency: Cronbach’s alpha coefficients

were calculated. A value of 0.70 or above indicates

that individual items provide an adequate contribution

to the overall scale [19].

• Test–retest reliability (reproducibility): Spearman’s rank

correlations were calculated for the LCOPD scores at the

two administrations. A high correlation indicates that the

scale produces an acceptably low level of random

measurement error.

• Convergent validity and divergent validity were evaluated

by assessing the level of association (Spearman rank

correlations) between scores on the LCOPD and those on

the SGRQ.

• Discriminative validity was assessed by relating LCOPD

scores to patient ratings of the overall severity of their

COPD (4-point scale from mild to very severe) and of their

general health (4-point scale ranging from poor to very

good). Clinician rating of the severity of the patient’s

COPD (3-point scale mild to severe) and whether they had

experienced an exacerbation requiring hospitalization or

unscheduled visits to a doctor in the previous week were

also available in the USA. Non-parametric tests for

independent samples (Mann–Whitney U Test for two

groups and Kruskal–Wallis Test for three or more groups)

were employed to test for differences as the questionnaire

data were ordinal in nature.

Results

Demographic information about the different samples used

in the study is shown in Table 1. Missing values are

excluded from the table.

Item generation

Qualitative, unstructured interviews were conducted with

29 UK patients, while 14 US patients took part in two focus

groups. Details of the sample are shown in Table 1.

Interviews lasted between 1 and 3.5 h and focus groups

were 1.5 h in duration. A large initial pool of several

hundred potential items was generated from the interviews

and focus groups, which included all statements identified.

These statements were then categorized into similar themes

with several statements representing each theme. The UK

and US researchers then met to reduce the initial pool by

selecting a subset of the items from each theme producing a

preliminary 37-item measure. The researchers ensured that

the language of the items selected would be acceptable to

future respondents in each country. Small differences in the

wording of items and instructions were necessary to ensure

conceptual equivalence between the two language versions

of the preliminary 37-item LCOPD. Each item had a True/

Not true response option for ease of completion.

It was clear from the interviews that COPD has a con-

siderable adverse impact on many aspects of the lives of

affected individuals. Figure 1 shows the conceptual

Qual Life Res (2011) 20:1043–1052 1045

123

framework for the LCOPD, illustrating how the issues raised

during the interviews relate to needs and quality of life

impact.

Cognitive debriefing interviews

Cognitive debriefing interviews were conducted with

19 patients in the UK and 16 in the USA. Demo-

graphic details of the sample are shown in Table 1. The

questionnaires were well received by participants who

found them relevant, comprehensible, easy and quick to

complete. A few changes to the questionnaire were

required. For example, the item I constantly have to think

about my medication was added as this issue was sug-

gested by several interviewees. The item I never wake up

feeling refreshed was deleted as some interviewees made

a mistake when responding since the response ‘Not true’

represented a double negative. I’m not confident about

going out alone was also deleted as this item was inter-

preted in terms of security rather than physical disability

by some respondents. The resulting draft LCOPD had 33

items.

Table 1 Sample characteristics

Qualitative interviews/focus groups Cognitive debriefing interviews Validation surveys

UK US UK US UK US

Sample size 29 14 19 16 162 145

Number (%) of male 16 (55.2) 6 (42.9) 9 (47.4) 8 (50.0) 71 (43.8) 67 (46.2)

Mean (SD) age (years) 66.5 (9.4) 64.9 (13.6) 65.8 (8.7) 64.4 (9.3) 69.3 (9.3) 71.7 (10.1)

Age range (years) min–max 51.6–91.2 33.0–80.0 52.0–80.0 48.0–77.0 48.3–91.1 45.0–95.0

Mean (SD) time since diagnosis 10.6 (11.3) 12.1 (9.5) 9.7 (14.2) 14.0 (15.0) 12.3 (14.0) 7.5 (6.3)

Perceived severity of COPD

Mild (%) 16 (9.9) 36 (25.2)

Moderate (%) 66 (41.0) 69 (48.3)

Severe (%) 63 (39.1) 28 (19.6)

Very severe (%) 16 (9.9) 10 (7.0)

Perceived general health

Very good (%) 3 (1.9) 7 (5.4)

Good (%) 27 (17.1) 43 (33.1)

Fair (%) 60 (38.0) 51 (39.2)

Poor (%) 68 (43.0) 29 (22.3)

Overall impact on life

COPD

Needs affected

Safety & security needs

Self-actualisationneeds

Independence needs

Self esteem needs Control needs Social and relationship

needs

Loss of spontaneity

Loss of role Fear of future

Panic at helplessness

Fear of going out alone

Trapped in house

Dependent on treatment

Selfconsciousness

Embarrassment

Loss of freedom

Require help

Reduced self-confidence

Controlled by COPD

Let down by body

Restrictedcapacity

Uncertainty – can’t plan for

future

Unable/less desire to socialise

Restrictedactivities

Let down friends and family

Fig. 1 LCOPD conceptual

framework

1046 Qual Life Res (2011) 20:1043–1052

123

Validation study

The preliminary LCOPD was completed by 162 UK and

145 US patients on two occasions, approximately 2 weeks

apart. Sample details are shown in Table 1.

Scaling and item reduction

Rasch analysis was applied separately to the UK and US

data as the scales were intended to be independent mea-

sures. Initially, the draft LCOPD misfit the Rasch model in

both countries (v2, P \ .01). This was caused by individual

items failing to fit the model. For example, patients were

likely to affirm the item I’m embarrassed about my

coughing irrespective of their level of QoL. Consequently,

the item did not discriminate between disease severity

groups and was removed from the scale. Similarly,

respondents over the age of 70 were less likely to affirm the

item I feel older than my years.

The item reduction process was primarily driven by item

fit, residuals, item location and DIF. However, it was

considered important to ensure that the scale retained the

face and content validity established in the cognitive

debriefing interviews. Therefore, the content and meaning

of the items were taken into account before removal due to

redundancy. Items that covered an issue not captured by

other items in the scale were retained.

The item reduction process was an iterative one since

item fit is influenced by the removal of other items. Items

were removed individually, and the analyses re-run. During

this process, 11 items were removed from the UK and US

measures creating final scales with 22-items. This version

of the LCOPD fits the Rasch model (P [ 0.05) in both

countries (Table 2). It was also found that all items in the

UK and US versions fit the Rasch model.

Examples from the final, 22-item version of the LCOPD

are shown in Table 3.

There was a good spread of items on the QoL trait in both

countries (Figs. 2, 3 respectively). The logit (severity) cov-

erage (the distance between most severe and mildest items)

was 5.92 in the UK and 5.60 in the USA. A majority of

respondents in each country fit within the range of QoL

severity measured by the items—indicating that their scores

were valid. The coverage of patient severity by items in the

USA appeared to be marginally better than that in the UK. The

item assessing the greatest impairment of QoL (the most

severe item) in the UK and USA was I rarely go out of the

house (location = 2.41 logits in both countries). The least

QoL impairment (the mildest item) in both countries was I

have to pace myself (UK location = -3.51 logits, US loca-

tion = -3.19 logits). It was encouraging to note that the item

Table 2 Final overall fit statistics

Language Item–trait interaction v2 PSI Item–person interaction

Items Persons

Mean SD Mean SD

UK 0.38 0.91 -0.23 1.08 -0.24 0.73

US 0.43 0.91 -0.36 0.76 -0.25 0.76

Table 3 Example items from the LCOPD

I can’t do things on the spur of the moment

I feel like a prisoner in my own home

My breathing makes me self conscious

I feel dependent on others

My illness frightens me

------------------------------------------------------------------------

Location (Logits) Persons Items -----------------------------------------5.0 |

| | |

ooooooooo | 4.0 |

| | |

oooooooooooo | 3.0 o |

| oooo |

| Xoooooooooooooo |

2.0 o | oooooooooo | X

o | Xooooooooooo |

oooooooooooooo | 1.0 oooooooooooo | XX

| Xooooooooooooo | X

oooo | Xooooooo | XX

0.0 oooo | XXoooo | XX

| Xooooo | X

oooooooo | -1.0 ooooo | XX

| oo |

ooo | | XXX

-2.0 oo | |

oo | |

o | -3.0 ooo |

| |

oo | X|

-4.0 | | |

o | ooooooo |

-5.0 | -------------------------------------------

o = 1 Person X = 1 item

Fig. 2 Final UK LCOPD item map

Qual Life Res (2011) 20:1043–1052 1047

123

ordering, location and overall range of item coverage were

similar in each country.

Traditional psychometric analyses

Scores on the final LCOPD can range from 0 to 22,

depending on the number of items affirmed. A high score

indicates that COPD has a major negative impact on the

QoL of the respondent. Table 4 shows the descriptive

scores for the LCOPD at first administration. It can be seen

that there is a good spread of scores with minimal floor and

ceiling effects. No differences in scores were found on the

basis of demographic factors in either country.

Internal consistency and reproducibility

Alpha coefficients were high for both language versions

(0.92) indicating that the LCOPD has good interrelatedness

of items. Test–retest reliability was also high; 0.89 in the

UK (n = 152) and 0.83 in the US (n = 35).

Convergent validity

Table 5 shows correlations between scores on the LCOPD

and SGRQ. As expected, the LCOPD correlations were

highest in the UK and USA with the SGRQ Impact Scale,

which is more closely related to QoL than, for example, the

SGRQ symptom scale.

Discriminative validity

Figures 4, 5, 6 and Table 6 provide LCOPD scores by

known groups. The measure was able to distinguish

between respondents according to:

-------------------------------------------------------------Location Persons Items-----------------------------------------

5.0 | | | | |

4.0 o | | | |

oooo | 3.0 o |

| ooo |

| Xoooo |

2.0 o | ooo | X

| ooo |

ooooooo | XX 1.0 oo | X

| X oooooooo | X

oooooo | ooooooo | XX

0.0 ooooooo | XXXXX ooooo | XX

oooooooo | | X

oooooooo | -1.0 ooooooooo |

| X oooooo |

oooooooo | X |

-2.0 ooooooooo | | X

oooooo | X |

o | -3.0 oooo |

| X |

oooooooo | |

-4.0 | | |

ooooooooooo | |

-5.0 | ----------------------------------------------

o = 1 Person X = 1 item

Fig. 3 Final US item map

Table 4 Final LCOPD descriptive statistics

Statistic UK USA

n 162 134

Mean 13.5 9.1

Standard deviation 6.2 6.1

Median 15.0 8.5

Inter-quartile range 9–18 4–14

Range 0–22 0–22

% Scoring minimum (0) 4.9 6.7

% Scoring maximum (22) 3.6 0.7

Table 5 Correlations between scores on the LCOPD and those on the

SGRQ

UK LCOPD US LCOPD

SGRQ—symptoms 0.39 0.66

SGRQ—activity 0.59 0.79

SGRQ—impact 0.79 0.85

All correlations significant at the 0.01 level (two-tailed)

0

2

4

6

8

10

12

14

16

18

20

22

Mild Moderate Severe

Mea

n L

CO

PD

sco

re

Severity rating

P < 0.01

Fig. 4 Mean LCOPD scores by clinician ratings of severity (USA)

1048 Qual Life Res (2011) 20:1043–1052

123

• clinician-rated severity of COPD in the USA (Fig. 4),

• patient-rated severity of COPD (Fig. 5),

• perceived general health (Fig. 6),

• whether the patient requires oxygen therapy (Table 6),

• whether respondents had experienced an exacerbation

during the previous week (Table 6),

• whether respondents were working or unable to work

due to their COPD (Table 6)

In all cases, patients reporting more severe COPD or

worse health scored significantly higher on the LCOPD

than those reporting milder COPD or better health.

Discussion

Patient-reported outcome measures cover a range of dif-

ferent types of outcome. The common link between them

is that the information they collect is reported by the

patient without any interpretation from others. This does

not imply that they necessarily measure issues that are of

concern or importance to the patient. The main patient-

reported outcomes measured are impairment, disability

(activity limitation), health-related quality of life (HRQL)

and QoL.

Fig. 5 Mean LCOPD scores by

patient ratings of severity

Fig. 6 Mean LCOPD scores by

patient ratings of general health

Qual Life Res (2011) 20:1043–1052 1049

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The constructs of impairment and disability have been

clearly defined by the World Health Organization [20, 21].

Impairment is any loss or abnormality of psychological,

physiological or anatomical structure or function and

equates to symptoms. This outcome is concerned with

disturbances at the level of the organ and examples include

anxiety, fatigue, breathlessness and problems sleeping.

Thus, impairment is useful for determining the impact of

disease from a clinical viewpoint providing, for example,

an indication of disease severity or the safety of a product.

The importance of assessing this construct in a clinical trial

is clear and rarely questioned. However, the patient may

not be concerned about specific symptoms.

A disability is any restriction or lack of ability to per-

form an activity in the manner or within the range con-

sidered normal for a human. Examples include problems

with dressing, walking or personal care. The assessment of

disability is valuable for planning interventions and reha-

bilitation services. Again, the outcome is not necessarily of

primary interest to the patient who may not be concerned

about restricted mobility or limited social interaction.

Health-related quality of life, as defined by different

authors, equates primarily to a mixture of impairment and

disability outcomes. It has been considered as ‘the capacity

to perform the usual daily activities for a person’s age and

major social role’ [22]. There is general agreement that

HRQL is multidimensional, but no consensus exists on the

domains that should be included [23–25]. The term HRQL

is misleading as it implies that QoL is being measured. In

fact, clear distinctions have been made between HRQL and

QoL [26–28] with the latter seen as going beyond the

measurement of impairment and disability. Bradley [29]

argues that ‘clinicians may be misled into thinking that

findings based on a (HRQL) instrument indicate that

treatments do not damage QoL when all the data reveal is

that treatments do not damage perceived health’.

The consequences of disease and its treatment (as

assessed by HRQL) represent one group of influences on

QoL. However, there are many more including personality,

economic status, environment, social relationships and

culture. The extent to which an impairment or disability

influences QoL is also dependent on these other influences

that cannot be separated from the impact of disease. For

example, the effect of respiratory disease on an individual

depends on the climate, environment, quality of personal

relationships, stage of life, nature of employment and many

other factors. Patients may give up functions that become

problematic, such as those requiring physical activity, and

take up other more passive leisure activities in order to

maintain their QoL.

Several studies have shown that interventions can

influence patient-reported outcomes when they do not

affect traditional outcome parameters [9]. Chavannes and

colleagues argue that investigators have to consider the

need for the evaluation of drugs in terms of patient-

reported outcomes and policy-makers should encourage

this approach [8]. Indeed, improving QoL is considered to

be a major goal in several widely recognized guidelines for

the management of COPD [32–36]. Unfortunately, inves-

tigators often select outcome measures designed for a dif-

ferent purpose. For example, generic measures such as the

SF-36 [37], Nottingham Health Profile [38] and Sickness

Impact Profile, Hospital Anxiety and Depression Scale and

Mood Adjective Check List [39] have been employed in

recent studies. Such generic measures do not measure QoL

but rather address HRQL. Furthermore, they are accepted

as being less sensitive to change than disease-specific

scales [7]. The SGRQ [14] is the most widely used and

probably the best measure available for the assessment of

symptoms and/or activity limitations in COPD. However,

the SGRQ does not cover the construct of QoL in sufficient

detail to be considered a measure of QoL impact.

Quality of life is the primary outcome of relevance and

importance to patients. It should provide a summary of the

impact of disease and its treatment on patients. In this

respect, it is not intended to be an aid to diagnosis or a

guide to the most appropriate intervention for a specific

patient. However, it should be able to determine which of

the alternative interventions is superior for patients as a

whole within the context of a clinical trial. The pharma-

ceutical industry has been collecting patient-reported out-

come data in clinical trials for several years. Partly in

response to this, health authorities are beginning to require

Table 6 Discriminative validity of the LCOPD

Known groups UK USA

N Mean (SD) N Mean (SD)

Gender

Male 71 13.4 (6.0) 64 9.0 (5.8)

Female 88 13.7 (6.3) 66 9.2 (6.5)

P 0.76 0.81

Employment

Working 8 10 (8.1) 22 5.8 (4.6)

Not working due to COPD 52 15.7 (5.1) 18 14.2 (4.9)

P \.01 \.001

Oxygen use

No 91 11.4 (6.7) 85 7.7 (6)

Yes 71 16.3 (4.2) 38 12 (5.4)

P \.001 \.001

Exacerbation in last week?

No – – 114 8.3 (5.9)

Yes – – 19 13.5 (5.9)

P – \.001

1050 Qual Life Res (2011) 20:1043–1052

123

evidence for new products that there are benefits for

patients that go beyond traditional clinical outcomes [30,

31]. Such ‘QoL-type’ data are also required by payers to

justify the high cost of new products. It is likely that good

QoL assessment will be required more frequently in the

future.

This paper describes the development and validation of

a new measure of QoL specific to COPD—the LCOPD.

The measure was designed to assess the overall impact of

COPD and its treatment from the patients’ perspective. Its

content was generated directly from patients by means of

qualitative, unstructured interviews and focus groups,

ensuring that the final measure covered issues of impor-

tance to patients—a fundamental requirement for QoL

measures. The LCOPD is short, quick and easy to complete

and score, making it suitable for inclusion in clinical

studies and trials. To this end, adaptations of the LCOPD

are currently in development for several countries.

The LCOPD is unidimensional, and therefore, it is valid

to add together individual item scores to obtain an overall

score. The measure has good psychometric properties as it

was shown to be reproducible and valid in both the UK and

USA. Floor and ceiling effects in both countries were

small, suggesting the range of coverage of QoL is appro-

priate for such patient groups. An advantage of the

LCOPD, resulting from its unidimensionality, is that it

provides a holistic assessment of the impact of living with

COPD in the form of an index or single number. Such an

index aids the interpretation of the overall outcomes of

clinical trials. The LCOPD can be used in conjunction with

clinical assessments and other measures (such as the

SGRQ) that are familiar to researchers and physicians. This

would allow a wider range of outcomes to be assessed in

clinical studies.

The results reported above confirm the preliminary

validity of the LCOPD. Its potential for use as a simple

assessment tool in clinical practice to assess the impact of

the disease on the patient (for example, in initial assess-

ment in pulmonary rehabilitation) has been established. A

further study is needed to determine whether the scale is

able to measure change in QoL in longitudinal studies and

to collect data that will allow scores (and changes in

scores) to be interpreted in terms of clinical importance.

Such a study should also investigate the relations between

clinical outcomes and QoL in COPD.

Conclusions

The LCOPD is a new QoL measure examining the every-

day impact of living with COPD. It was developed based

on interviews with patients and measures how COPD

affects patients from their own perspective. The LCOPD

demonstrates good scaling properties, convergent/diver-

gent validity, reliability and construct validity and may

prove valuable in understanding treatment benefits.

Acknowledgments The authors would like to acknowledge the help

of all the patients in the UK and USA who participated in the study.

They would also like to thank S Rebecca Crawford for her assistance

with editing of the manuscript and Novartis AG for their financial

support.

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