A short questionnaire for the assessment of quality of life in patients with chronic obstructive pulmonary disease: psychometric properties of VQ11
© Ninot et al.; licensee BioMed Central Ltd. 2013
Received: 21 June 2013
Accepted: 25 September 2013
Published: 25 October 2013
There is a need for a validated short instrument that can be used in routine practice to quantify potential short-term change in Health-Related Quality of Life (HRQoL) in patients with chronic obstructive pulmonary disease (COPD). Our aim is to determine the validity and reliability of the VQ11 questionnaire dedicated to the routine assessment of HRQoL.
181 COPD patients (40–85 yrs, I to IV GOLD stages) completed the VQ11, and several tests. One week later, 49 of these patients completed the VQ11 again.
Confirmatory factor analysis supported the two-level hierarchical structure of the VQ11 with 11 items covering three components and HRQoL at a higher level. The VQ11 showed good internal consistency and good reproducibility (r = 0.88). Concurrent validity showed significant correlations between VQ11 total scores and St George’s Respiratory Questionnaire-C (r = 0.70), Short Form-36 (r = -0.66 for the physical component and -0.63 for the mental component). We obtained significant correlations with MRC Dyspnea Grades (r = 0.59), the Hospital Anxiety and Depression Scale total score (r = 0.62), and the BODE index (r = 0.53).
The VQ11 has good measurement properties and provides a valid and reliable measure of COPD-specific HRQoL. It is ready for use in routine practice.
The study was approved by the University of Montpellier 1 Ethics Committee and the Regional Ethics Committee (authorization number: A00332-53).
KeywordsChronic obstructive pulmonary disease Brief questionnaire Health-related quality of life Validity VQ11
Body mass index
Chronic obstructive pulmonary disease
Chronic respiratory disease questionnaire
Comparative fit index
COPD assessment test
Confirmatory factor analysis
COPD clinical questionnaire
Forced expiratory volume in 1 s
Forced vital capacity
Health-related quality of life
Hospitalization anxiety depression scale
Modified medical research council
Pulmonary function tests
Root mean square error of approximation
Short form chronic respiratory disease questionnaire
Six-minute walk test
St George’s respiratory questionnaire
Visual analog scale
Visual simplified respiratory questionnaire.
Self-administered questionnaires are required in order to estimate global outcomes of COPD . Available disease-specific Health-Related Quality of Life (HRQoL) measures, mainly the St George’s Respiratory Questionnaire (SGRQ) , and the Chronic Respiratory Disease Questionnaire (CRDQ) , are reliable and valid, and widely used in clinical trials. There is increasing evidence that HRQoL questionnaires can also be useful in clinical settings ; however, existing instruments are lengthy and have complex scoring algorithms, making them poorly suited for routine use in clinical practice and repeated assessment. Most patients require short questionnaires (reducing fatigue, eliminating redundancy of items, and facilitating spontaneous responses).
A standardized, patient-centered assessment instrument covering key aspects of COPD HRQoL facilitates information gathering and improves communication between patient and clinician, particularly for general practitioners. An ideal instrument would identify specific areas of greater severity that would serve as focal points for targeted management or the evaluation of management goals, thereby improving both the process and outcome of care. The instrument must be sensitive enough to measure mild-moderate COPD , but also reliable [6, 7], valid for evaluative studies, and useful for determining rehabilitation routines. Previous studies have shown significant changes in quality of life score between three and six months in patients with COPD participating in a rehabilitation program  or, after discharge from a rehabilitation program [9, 10].
Psychometric properties of short HRQoL questionnaires for COPD patients
Functional Psychological Social
Frequency or intensity
Frequency or intensity
Frequency or intensity
0 - 6 (Total)
1 - 14 per dimension
0 - 80
0 - 40
11 - 55
From 77 to 10
From 20 to 8
From 18 to 8
From 21 to 8
From 24 to 11
Confirmative factor analysis
Principal component analysis
Principal component analysis
Structural equation modeling
r Total SGRQ
-.07 to -.28
In practice, the 8-item VSRQ and the 8-item CAT include no subscales. Conversely, the 8-item SF-CRDQ does not provide a total score. The SF-CRDQ, VSRQ and CAT mix answers for frequency and intensity, which could be difficult to distinguish in patients with COPD.
Conceptually, these instruments establish confusions to estimate the impact of COPD between health status and HRQoL. The concept of health status refers to the impact of health on the individual’s ability to perform daily life activities and to benefit from them . HRQoL refers to the three broad dimensions of health: physical (e.g., autonomy, capacity, symptoms), psychological (e.g., pain, self-esteem, and symptoms), and social (e.g., social relationship, family relationship) . Thus, an instrument dedicated to the measure of HRQoL needs to provide 3 dimensions (physical, psychological and social) and an overall total score.
Item coverage of short HRQoL questionnaires for COPD patients
Shortness of breath
Sexual life trouble
Life project limitation
Social support lack
Social life restriction
Psychometrically, for all the above instruments but the CAT and VQ11, the item reduction selection was made by a committee of experts and without the use of statistical analysis such as Confirmatory Factor Analysis. A previous study showed that the VQ11 has good content and internal properties . This study was carried out to verify its construct’s validity and reliability in comparison to other short instruments (Table 1).
Clinical characteristics and HRQoL measures for 181 patients (123 males and 58 females)
Sociodemographic and overall characteristics
Pre-BD FEV1 (ml)
FEV1 (% pred)
Dyspnea 6MWD end
6MWT distance (m)
6MWT distance (% pred)
SGRQ-C Symptoms score
SGRQ-C Activity score
SGRQ-C Impact score
SGRQ-C Total score
VQ11 Functional (3–15)
VQ11 Psychological (4–20)
VQ11 Social (4–20)
VQ11 Total score (11–55)
SF-36 Physical functioning
SF-36 Role physical
SF-36 Role emotional
SF-36 Mental Health
SF-36 Social functioning
SF-36 Bodily pain
SF-36 General health perceptions
SF-36 Physical Component Scale
SF-36 Mental Component Scale
HADS Anxiety score (0–21)
HADS Depression score (0–21)
HADS Total score (0–42)
Physical self-worth (1–6)
Upon recruitment, the following examinations were performed for each participant: a clinical assessment, the collection of cardio-respiratory family history and number of exacerbations for respiratory (or other) reasons, a respiratory function examination (spirometry, blood gas analysis), an electrocardiogram, and a six-minute walk test (6MWT). Participants were also required to complete the experimental questionnaire, the external validity questionnaires (Medical Outcome Survey Short - SF-36, SGRQ-C, Hospitalization Anxiety Depression Scale - HADS, Physical Self-Worth - PSW) and a datasheet on their socio-cultural situation. Appointments were made with participants who were able and willing to undergo a follow-up assessment one week later. Forty-nine participants completed the VQ11 again to test its reproducibility. To ensure uniform assessments in this multicentric study (Montpellier, Paris, Osséja), the medical and scientific committee of the healthcare network developed recommendations and one teaching session for a standard protocol for instrument use and patient assessment.
Completion of questionnaires
The participants completed the battery of self-administered questionnaires, presented in a randomized order, while resting between physical tests. Participants who took part in both sessions were examined by the same researcher on both occasions.
Content and structure of the VQ11 questionnaire and its cross-cultural translation by three native speakers of English
The following sentences express feelings about the consequences of COPD. For each sentence, tick the intensity that best reflects your feeling at this moment (from “not at all” to “extremely”). There are no wrong answers. Each one is personal.
Les phrases suivantes expriment des sentiments sur les conséquences de la BPCO. Pour chacune, cochez l’intensité qui vous correspond le mieux maintenant (de « pas du tout » à « extrêmement »). Aucune réponse n’est juste. Elle est avant tout personnelle.
I suffer from breathlessness
Je souffre de mon essoufflement
I am worried about my respiratory condition
Je me fais du souci pour mon état respiratoire
I feel my entourage (family, friends, etc.) misunderstands me
Je me sens incompris(e) par mon entourage
My respiratory condition prevents me from moving about as easily as I would like
Mon état respiratoire m’empêche de me déplacer comme je le voudrais
I feel sleepy during the day
Je suis somnolent(e) dans la journée
I feel unable to achieve my objectives
Je me sens incapable de réaliser mes projets
I quickly get tired when doing day-to-day activities
Je me fatigue rapidement dans les activités de la vie quotidienne
Physically, I am dissatisfied with what I can do
Physiquement. je suis insatisfait(e) de ce que je peux faire
My respiratory disease disrupts my social life
Ma maladie respiratoire perturbe ma vie sociale
I feel sad
Je me sens triste
My respiratory condition restricts my emotional life
Mon état respiratoire limite ma vie affective
Analyses of respiratory function
The pulmonary function tests (PFTs) included simple screening spirometry, formal lung volume measurement, diffusing capacity for carbon monoxide, and arterial blood gases. We measured the volume-time curve and the flow-volume loop, as well as FVC and FEV1 in order to calculate FEV1/FVC indices .
The 6MWT test was performed twice with more than 30 minutes between tests in order to allow heart rate and dyspnea to return to their initial rest values . A dyspnea score was measured on a 10-cm visual analog scale (VAS) before and immediately after the test.
CFA was used to confirm the theoretical model found during the internal validation (Statistical Software Mplus 5.1). Fit assessment of the CFA models was based on multiple indicators [32–34], including the Chi-square statistic (χ2), comparative fit index (CFI), Tucker-Lewis Index (TLI), root mean square error of approximation (RMSEA), and 90% confidence interval (CI) of the RMSEA. Values greater than 0.90 for CFI and TLI are considered to indicate adequate model fit, although values approaching 0.95 are preferable. Values smaller than 0.08 or 0.06 for the RMSEA indicate acceptable and good model fit, respectively [33, 34]. For the RMSEA 90% CI, values less than 0.05 for the lower bound (left side) and less than 0.08 for the upper bound (right side) or of 0 for the lower bound and less than 0.05 for the upper bound (right side) indicate acceptable and good model fit, respectively . Factor loadings, squared multiple correlations, standard errors and t values were inspected for appropriate sign and/or magnitude.
Concurrent validity was assessed by analyzing Pearson correlation coefficients between the dimensions of the study questionnaire and those of another questionnaire measuring similar concepts. Spearman correlation coefficients were calculated between the VQ11 (total and component scores) and other independent variables. In order to confirm good concurrent validity but no redundancy, the new questionnaire had to show moderate correlation (0.40 to 0.70) with a well-established mea surement tool.
Reliability is the degree to which an instrument is free from random error. It is evaluated by measuring internal consistency reliability and reproducibility. Internal consistency reliability refers to the homogeneity of the items of the scale and was assessed using Cronbach’s alpha. Reproducibility establishes the stability of an instrument over time in a stable population and was tested using a Pearson correlation.
One hundred eighty-one participants completed the study baseline questionnaires and 49 participants completed the follow-up questionnaires. The mean ± SD and range of the physiological and patient-reported outcomes for the study population are summarized in Table 3.
Reproducibility was assessed in terms of the correlations between the measures produced by the 49 COPD patients who were reassessed after a one-week period (42 patients under 10% of variation; 7 patients under 20% of variation). Correlation coefficients were 0.76 for the functional component (p < .01), 0.65 for the psychological component (p < .01), 0.73 for the social component (p < .01), and 0.88 for total VQ11 (p < .01).
Cronbach’s alphas were 0.80 for the functional component, 0.68 for the psychological component, 0.77 for the social component and 0.89 for the whole scale. Alphas computed using the Spearman-Brown formula were 0.91, 0.81 and 0.87, respectively.
The low correlations between VQ11 and FEV1 (functional component, -0.26; total, -0.19) suggest that there are no significant differences between groups classified by grade of severity and VQ11 score.
Clinical characteristics and HRQoL measures by quartiles of VQ11 score
(N = 45)
(N = 51)
(N = 37)
(N = 44)
P value $
Q1 < Q3; Q1 < Q2 < Q4
Pre-BD FEV1 (ml)
Q1 < Q3,Q4
FEV1 (% pred)
Q1 < Q3,Q4
Dyspnea 6MWD end
Q1 < Q4
6MWT distance (m)
Q1,Q2 < Q4
Q1,Q2 < Q4; Q1 < Q2,Q3
Q1 < Q3,Q4; Q2 < Q4
Q1 < Q2 < Q4; Q1 < Q3
Q1 < Q2 < Q3,Q4
Q1 < Q2 < Q3,Q4
Correlation between VQ11 and other variables of interest
FEV1 % pred
MMRC Dyspnea Grade
Dyspnea 6MWD start
Dyspnea 6MWD end
Dyspnea 6MWD difference
6MWT distance (m)
6MWT distance (% pred)
Correlation between VQ11 and other questionnaire scores
General health perceptions
Physical Component Scale
Mental Component Scale
This study examined the validity and reliability of the VQ11, a short, self-administered questionnaire specifically designed for repeated assessment of patients with COPD and for use in routine care. The results show that the VQ11 provides a simple and reliable measure of overall COPD-related HRQoL and physical, psychological, and social components of HRQoL as expected by experts .
The hierarchical structure of a preliminary version of the VQ11 had previously been tested on a sample of 166 COPD patients . Therefore, the initial aim of the present study was to use CFA to verify this factorial structure with a new sample of COPD patients. Our findings demonstrated that the higher-order factor model provided a satisfactory fit to the data and a better fit than the alternative models. These results confirm those from a previous study . The model contains physical, psychological, and social components, in line with guidelines for HRQoL questionnaires [17, 22, 34]. Our analysis showed that these components can be examined separately.
The concurrent validity of the VQ11 was confirmed by the correlation between VQ11 scores (for the individual components and for the total score) and the SF-36 or the SGRQ-C. VQ11 total scores strongly correlated with scores for the physical and mental components of the SF-36, and with scores on the eight scales that make up these components. As expected, the highest correlation was for the physical functioning scale . Also as expected, the highest correlations were between corresponding components of the VQ11 and the SF-36 (VQ11-functional scale and the SF-36 physical component and physical functioning scales; VQ11-psychological scale and SF-36 emotional role, energy/vitality, mental health, general health perceptions and mental component scales; VQ11-social scale and SF-36 social functioning scale). By contrast, the correlation between the component and total scores on the VQ11 and the SF-36 bodily pain scale was not particularly strong. However, because the SF-36 was not designed to measure sleep disturbances and respiratory complaints, this relatively weak correlation does not affect the concurrent validity of the VQ11. As expected, VQ11 total scores correlated well with SGRQ-C scores and three specific domains.
The three components of the VQ11 are disease-specific domains of HRQoL for COPD patients. VQ11 functional scores correlated with dyspnea (MMRC grade and 6MWT distance), BODE index, exercise tolerance (6MWT distance), the activity and impact scores of the SGRQ-C, and the physical functioning and physical components of the SF-36. The items of the VQ11 reflect the main symptoms perceived by patients with COPD, dyspnea , physical limitation  and fatigue [37, 38, 40].
Significant correlations were found between the psychological component of the VQ11 and the HADS anxiety and depression scales, the SGRQ-C impact scale, the emotional role and mental components of the SF36, and physical self-worth (defined as physical self-esteem). This emphasizes that disease-associated anxiety and depression are important HRQoL factors for COPD patients. The degree of anxiety felt by COPD patients has been shown to be related to their degree of pulmonary dysfunction .
The social component of VQ11 correlated with the social functioning and mental components of the SF36. Social relationships are affected by chronic respiratory disease, especially in patients with severe respiratory insufficiency who often depend on close social relationships to manage daily activities . Patients with COPD experience losses in several areas of their lives, and they may feel useless, experience reduced sexual activity, depend on others for their personal care and lose interest in future projects.
The total, functional, psychological, and social components of the VQ11 showed good reliability over a period of one week for patients without clinical change. The correlation coefficient for the psychological component was the lowest. This result can be explained by intra-individual variability in the perception of disease and health status. A recent study noted higher day-to-day instability in self-esteem, which is a major correlate factor of HRQoL for COPD patients compared with healthy adults . Consequently, it would be advisable for clinicians to ask patients to complete the VQ11 every three to six months, in order to assess the stability of patients’ perceptions of their illness, as this perception may be a sign of vulnerability and of the likelihood they will not fully adhere to their treatment.
There were limitations to the study. The sample was relatively homogenous, with all subjects having moderate to severe COPD, the majority being ex-smokers with a significant smoking history. The concept of quality of life and its implications on daily life are different for men and women . We could not validate the new questionnaire separately for men and women due to the small sample size. The VQ11 also needs to be studied in other ethnic populations and cultures for cross-cultural validity. In addition, the responsiveness of the VQ11 to interventions and comparisons with other quality of life questionnaires is also required. Last, using a new patient-reported outcomes questionnaire requires the determination of the minimal clinically important difference .
In practice, there are four general benefits to using the VQ11: (1) It helps clinicians quickly detect the worsening of HRQoL in COPD patients. This deterioration can then be explained by the acknowledgment of COPD, poor disease self-management (routine or acute situation), the presence of comorbidities (depression, sleep trouble, metabolic syndrome…) and/or weak support from family and friends. Possible consequences include an increase in the exacerbation risk and aggravation of COPD, the development of health-risk behavior or of a new disease, and/or the deterioration of communication with caregivers, family or friends. (2) The three components of the VQ11 allow caregivers to assess and correct a number of situations: based on a high score on the functional component, informed decisions can be made on therapy, modification of current treatment, new assessment, physiotherapy or comprehensive rehabilitation; with a high score on the psychological component, those decisions can be made regarding new assessment, psychological support, education, or comprehensive rehabilitation; finally, with a high score on the social component, decisions can be made concerning social support, psychological support, education, membership in a health network or patients association. (3) Based on the anticipated validation of a Minimal Clinically Important Difference, the VQ11 can also help monitor the efficacy of an individual’s therapeutic decision. (4) Lastly, the VQ11 provides clinicians with meaningful cues to examine a COPD life consequence more specifically when an answer to an item is more than three. Moreover, the back of the form includes an educational message with a space for drawing and commenting in which individual messages can be exchanged between patients and caregivers, family or friends.
This study showed the validity and reliability of the VQ11, a short, self-administered questionnaire specifically designed for repeated assessment of patients with COPD and for use in routine care. The VQ11 provides clinicians and patients with a simple and reliable measure of overall COPD-related HRQoL. The VQ11 facilitates discussions about the overall consequences of COPD arising from the illness’s physical symptoms and psychological perceptions, observance behaviors, health behaviors, life projects with COPD, and social support. Additional information is needed to provide responsiveness to change at the individual patient level, an essential feature for its use in clinical practice.
The authors wish to thank A. Herkert, S. Stélianides, S. Jérome, K. Nassih, J. Desplan, M. Poulain, N. Oliver, M. Desplan, N. Fernandes, A. Morin, G. Garcia, L. Achouh, A. Guetta, C. Chouaid, G. Damien, G. Vallet, N. Heraud, M. Hayot, A. Couillard, G. Moullec, A. Pires, E. Chavignay, P. Bernard, F. Gouzi, M. Sabaté, S. Fiocco, M. Carayol, P. Jones and N. Roche for their contributions to the organization of the study and their many helpful comments.
Institutions at which the work was carried out
Service Central de Physiologie Clinique, Unité d’Exploration Respiratoire. CHRU Arnaud de Villeneuve, Montpellier
CHRU Béclère, Clamart
CHRU St-Antoine, Paris
Cabinet de pneumologie, Bagneux
Clinique du Souffle La Solane, Osséja
Clinique du Souffle La Vallonie, Lodève
Réseau AIR + R, Montpellier
Source of funding
This work was supported by Montpellier University Hospital (CHRU), GlaxoSmithKline France, Novartis, Société de Pneumologie de Langue Française, Association Nationale pour les Traitements à Domicile les Innovations et la Recherche, Fontalvie Group.
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