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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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Best-fitting model from the confirmatory factor analysis in study 2.
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fig2: Best-fitting model from the confirmatory factor analysis in study 2.

Mentions: Neither the structure found in the first study (CFI 0.87, NFI 0.85, RMSEA 0.14, lower limit 0.12) nor the original model (CFI 0.80, NFI 0.79, RMSEA 0.18, lower limit 0.16) revealed an adequate fit of the data. An inadequate model fit can be the result of severe violations of normality. Therefore, skewness, kurtosis and response distributions were reviewed again, and the results were consistent with those of study 1 (Table 4). Subsequently removing items 3, 4, 9 and 10 from the model because of floor effects and non-normal distributions led to an excellent model fit with two, more homogeneous dimensions measuring ‘dyspnoea’ (α=0.86) and ‘cough’ (α=0.86) (Figure 2): CFI 0.98; NFI 0.97; RMSEA 0.08 and lower limit 0.04. Moreover, the remaining items cover the frequency and impact of the key symptoms that characterise an exacerbation (dyspnoea, cough and sputum production).25


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)

Best-fitting model from the confirmatory factor analysis in study 2.
© Copyright Policy - open-access
Related In: Results  -  Collection

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

fig2: Best-fitting model from the confirmatory factor analysis in study 2.
Mentions: Neither the structure found in the first study (CFI 0.87, NFI 0.85, RMSEA 0.14, lower limit 0.12) nor the original model (CFI 0.80, NFI 0.79, RMSEA 0.18, lower limit 0.16) revealed an adequate fit of the data. An inadequate model fit can be the result of severe violations of normality. Therefore, skewness, kurtosis and response distributions were reviewed again, and the results were consistent with those of study 1 (Table 4). Subsequently removing items 3, 4, 9 and 10 from the model because of floor effects and non-normal distributions led to an excellent model fit with two, more homogeneous dimensions measuring ‘dyspnoea’ (α=0.86) and ‘cough’ (α=0.86) (Figure 2): CFI 0.98; NFI 0.97; RMSEA 0.08 and lower limit 0.04. Moreover, the remaining items cover the frequency and impact of the key symptoms that characterise an exacerbation (dyspnoea, cough and sputum production).25

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