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Patient-reported outcomes in primary care patients with COPD: psychometric properties and usefulness of the Clinical COPD Questionnaire (CCQ). A cross-sectional study.

Pommer AM, Pouwer F, Denollet J, Meijer JW, Pop VJ - NPJ Prim Care Respir Med (2014)

Bottom Line: In study 2 (N=244), confirmatory factor analysis (CFA) was conducted to evaluate the model fit of the structure found in study 1.This structure, however, was not confirmed in study 2, nor was the original structure.However, subsequently removing items that violated the assumption of a normal response distribution did result in an excellent model fit with two dimensions measuring 'dyspnoea' and 'cough' (CFA: comparative fit index (CFI) 0.98; normed fit index (NFI) 0.97; root mean squared error of approximation (RMSEA) 0.08 (0.04)).

View Article: PubMed Central - PubMed

Affiliation: Department of Medical and Clinical Psychology, Centre of Research on Psychology in Somatic diseases (CoRPS), TSB, Tilburg University, Tilburg, The Netherlands.

ABSTRACT

Background: Chronic obstructive pulmonary disease (COPD) is a common disease with considerable consequences for patients' daily lives. The Clinical COPD Questionnaire (CCQ) was designed to measure these consequences in daily practice. Although the CCQ is widely used, its original structure has never been tested.

Aims: This study examines the psychometric properties of the CCQ with regard to its latent structure in a sample of primary care patients with COPD.

Methods: Two cross-sectional studies were conducted; in study 1 (N=243) exploratory analyses, including exploratory factor analysis (EFA) and Mokken scale analysis, were performed to explore the latent structure of the CCQ. In study 2 (N=244), confirmatory factor analysis (CFA) was conducted to evaluate the model fit of the structure found in study 1.

Results: Both EFA and Mokken scale analysis revealed a structure of two dimensions ('general impact' α=0.91 and 'cough' α=0.84). This structure, however, was not confirmed in study 2, nor was the original structure. However, subsequently removing items that violated the assumption of a normal response distribution did result in an excellent model fit with two dimensions measuring 'dyspnoea' and 'cough' (CFA: comparative fit index (CFI) 0.98; normed fit index (NFI) 0.97; root mean squared error of approximation (RMSEA) 0.08 (0.04)).

Conclusions: In primary care, factor analyses on the CCQ revealed a two-component structure measuring 'general impact', and 'cough'. A shortened and more specific version of the CCQ could be regarded as a useful instrument to screen for exacerbations by measuring dyspnoea, coughing and producing phlegm.

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Related in: MedlinePlus

The scree plot from the exploratory factor analysis in study 1.
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fig1: The scree plot from the exploratory factor analysis in study 1.

Mentions: All assumptions to perform EFA were met, the Kaiser–Meyer–Oklin value was >0.60 (0.86) and Bartlett’s test of sphericity was significant (P<0.01). The scree test (Figure 1) revealed a clear pattern of two dimensions that together explained 67% of all variance (‘general impact’ 53% and ‘cough’ 14%). In addition, all corresponding factor loadings were >0.65 (Table 3). With regard to the Mokken scale analysis, a lower bound of 0.4–0.5 (comparable with factor loadings >0.4) resulted in the same two dimensions with sufficient differential quality (H); the differential quality of ‘general impact’ varied between H 0.60 (lower bound 0.4) and H 0.66 (lower bound 0.5), with H 1.00 suggesting perfect differential quality. The differential quality of ‘cough’ was found to be H 0.76. ‘General impact’ was covered by eight items with α=0.91, ‘cough’ was covered by two items with α=0.84.


Patient-reported outcomes in primary care patients with COPD: psychometric properties and usefulness of the Clinical COPD Questionnaire (CCQ). A cross-sectional study.

Pommer AM, Pouwer F, Denollet J, Meijer JW, Pop VJ - NPJ Prim Care Respir Med (2014)

The scree plot from the exploratory factor analysis in study 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4373388&req=5

fig1: The scree plot from the exploratory factor analysis in study 1.
Mentions: All assumptions to perform EFA were met, the Kaiser–Meyer–Oklin value was >0.60 (0.86) and Bartlett’s test of sphericity was significant (P<0.01). The scree test (Figure 1) revealed a clear pattern of two dimensions that together explained 67% of all variance (‘general impact’ 53% and ‘cough’ 14%). In addition, all corresponding factor loadings were >0.65 (Table 3). With regard to the Mokken scale analysis, a lower bound of 0.4–0.5 (comparable with factor loadings >0.4) resulted in the same two dimensions with sufficient differential quality (H); the differential quality of ‘general impact’ varied between H 0.60 (lower bound 0.4) and H 0.66 (lower bound 0.5), with H 1.00 suggesting perfect differential quality. The differential quality of ‘cough’ was found to be H 0.76. ‘General impact’ was covered by eight items with α=0.91, ‘cough’ was covered by two items with α=0.84.

Bottom Line: In study 2 (N=244), confirmatory factor analysis (CFA) was conducted to evaluate the model fit of the structure found in study 1.This structure, however, was not confirmed in study 2, nor was the original structure.However, subsequently removing items that violated the assumption of a normal response distribution did result in an excellent model fit with two dimensions measuring 'dyspnoea' and 'cough' (CFA: comparative fit index (CFI) 0.98; normed fit index (NFI) 0.97; root mean squared error of approximation (RMSEA) 0.08 (0.04)).

View Article: PubMed Central - PubMed

Affiliation: Department of Medical and Clinical Psychology, Centre of Research on Psychology in Somatic diseases (CoRPS), TSB, Tilburg University, Tilburg, The Netherlands.

ABSTRACT

Background: Chronic obstructive pulmonary disease (COPD) is a common disease with considerable consequences for patients' daily lives. The Clinical COPD Questionnaire (CCQ) was designed to measure these consequences in daily practice. Although the CCQ is widely used, its original structure has never been tested.

Aims: This study examines the psychometric properties of the CCQ with regard to its latent structure in a sample of primary care patients with COPD.

Methods: Two cross-sectional studies were conducted; in study 1 (N=243) exploratory analyses, including exploratory factor analysis (EFA) and Mokken scale analysis, were performed to explore the latent structure of the CCQ. In study 2 (N=244), confirmatory factor analysis (CFA) was conducted to evaluate the model fit of the structure found in study 1.

Results: Both EFA and Mokken scale analysis revealed a structure of two dimensions ('general impact' α=0.91 and 'cough' α=0.84). This structure, however, was not confirmed in study 2, nor was the original structure. However, subsequently removing items that violated the assumption of a normal response distribution did result in an excellent model fit with two dimensions measuring 'dyspnoea' and 'cough' (CFA: comparative fit index (CFI) 0.98; normed fit index (NFI) 0.97; root mean squared error of approximation (RMSEA) 0.08 (0.04)).

Conclusions: In primary care, factor analyses on the CCQ revealed a two-component structure measuring 'general impact', and 'cough'. A shortened and more specific version of the CCQ could be regarded as a useful instrument to screen for exacerbations by measuring dyspnoea, coughing and producing phlegm.

Show MeSH
Related in: MedlinePlus