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COPD Diagnostic Questionnaire (CDQ) for selecting at-risk patients for spirometry: a cross-sectional study in Australian general practice.

Stanley AJ, Hasan I, Crockett AJ, van Schayck OC, Zwar NA - NPJ Prim Care Respir Med (2014)

Bottom Line: A cut point of 19.5 had the optimal combination of sensitivity (63%) and specificity (70%) with two-thirds below this cut point.A cut point of 14.5 corresponded to a sensitivity of 91%, specificity of 35% and negative predictive value of 96%, and 31% of patients below this cut point.We consider two possible cut points.

View Article: PubMed Central - PubMed

Affiliation: School of Public Health and Community Medicine, Faculty of Medicine, University of New South Wales, Kensington, New South Wales, Australia.

ABSTRACT

Background: Using the COPD Diagnostic Questionnaire (CDQ) as a selection tool for spirometry could potentially improve the efficiency and accuracy of chronic obstructive pulmonary disease (COPD) diagnosis in at-risk patients.

Aim: To identify an optimal single cut point for the CDQ that divides primary care patients into low or high likelihood of COPD, with the latter group undergoing spirometry.

Methods: Former or current smokers aged 40-85 years with no prior COPD diagnosis were invited to a case-finding appointment with the practice nurse at various general practices in Sydney, Australia. The CDQ was collected and pre- and post-bronchodilator spirometry was performed. Cases with complete CDQ data and spirometry meeting quality standards were analysed (1,054 out of 1,631 patients). CDQ cut points were selected from a receiver operating characteristic (ROC) curve.

Results: The area under the ROC curve was 0.713. A cut point of 19.5 had the optimal combination of sensitivity (63%) and specificity (70%) with two-thirds below this cut point. A cut point of 14.5 corresponded to a sensitivity of 91%, specificity of 35% and negative predictive value of 96%, and 31% of patients below this cut point.

Conclusions: The CDQ can be used to select patients at risk of COPD for spirometry using one cut point. We consider two possible cut points. The 19.5 cut point excludes a higher proportion of patients from undergoing spirometry with the trade-off of more false negatives. The 14.5 cut point has a high sensitivity and negative predictive value, includes more potential COPD cases but has a higher rate of false positives.

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Related in: MedlinePlus

Receiver operating characteristic (ROC) curve comparing the COPD Diagnostic Questionnaire score to chronic obstructive pulmonary disease diagnosis. Cut point 16.5—grey star; 19.5—black star. An ROCAUC of 0.5 is indicated by the solid diagonal line.
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fig1: Receiver operating characteristic (ROC) curve comparing the COPD Diagnostic Questionnaire score to chronic obstructive pulmonary disease diagnosis. Cut point 16.5—grey star; 19.5—black star. An ROCAUC of 0.5 is indicated by the solid diagonal line.

Mentions: Figure 1 shows the ROC curve and the position of the original two cut points. The ROCAUC was 0.713±0.023 with the higher cut point closer to the middle of the curve. Table 3 shows the sensitivity, specificity, predictive values and proportion of patients below various select cut points after ROC curve analysis. The sensitivity and specificity for the 16.5 cut point were 79.7 and 46.8%, respectively. The sensitivity and specificity for the 19.5 cut point were 63.0 and 70.1%, respectively. About two-thirds of patients scored below the 19.5 cut point and about 43% scored below the 16.5 cut point. The lowest cut point with at least 90% sensitivity was 14.5. This corresponded to a specificity of about 35%, positive predictive value of 17%, negative predicative value of 96% and a proportion below the cut point of 31%. A sensitivity of at least 95% corresponded to a cut point of 11.5, with sensitivity of 96.4%, specificity of about 19%, positive predictive value of 15%, negative predicative value of 97% and a proportion below the cut point of about 17%. The maximal positive predictive value of 29.4% corresponded to the 23.5 cut point, with sensitivity of about 30%, specificity of 90% and 87% of patients scoring below the cut point.


COPD Diagnostic Questionnaire (CDQ) for selecting at-risk patients for spirometry: a cross-sectional study in Australian general practice.

Stanley AJ, Hasan I, Crockett AJ, van Schayck OC, Zwar NA - NPJ Prim Care Respir Med (2014)

Receiver operating characteristic (ROC) curve comparing the COPD Diagnostic Questionnaire score to chronic obstructive pulmonary disease diagnosis. Cut point 16.5—grey star; 19.5—black star. An ROCAUC of 0.5 is indicated by the solid diagonal line.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4373382&req=5

fig1: Receiver operating characteristic (ROC) curve comparing the COPD Diagnostic Questionnaire score to chronic obstructive pulmonary disease diagnosis. Cut point 16.5—grey star; 19.5—black star. An ROCAUC of 0.5 is indicated by the solid diagonal line.
Mentions: Figure 1 shows the ROC curve and the position of the original two cut points. The ROCAUC was 0.713±0.023 with the higher cut point closer to the middle of the curve. Table 3 shows the sensitivity, specificity, predictive values and proportion of patients below various select cut points after ROC curve analysis. The sensitivity and specificity for the 16.5 cut point were 79.7 and 46.8%, respectively. The sensitivity and specificity for the 19.5 cut point were 63.0 and 70.1%, respectively. About two-thirds of patients scored below the 19.5 cut point and about 43% scored below the 16.5 cut point. The lowest cut point with at least 90% sensitivity was 14.5. This corresponded to a specificity of about 35%, positive predictive value of 17%, negative predicative value of 96% and a proportion below the cut point of 31%. A sensitivity of at least 95% corresponded to a cut point of 11.5, with sensitivity of 96.4%, specificity of about 19%, positive predictive value of 15%, negative predicative value of 97% and a proportion below the cut point of about 17%. The maximal positive predictive value of 29.4% corresponded to the 23.5 cut point, with sensitivity of about 30%, specificity of 90% and 87% of patients scoring below the cut point.

Bottom Line: A cut point of 19.5 had the optimal combination of sensitivity (63%) and specificity (70%) with two-thirds below this cut point.A cut point of 14.5 corresponded to a sensitivity of 91%, specificity of 35% and negative predictive value of 96%, and 31% of patients below this cut point.We consider two possible cut points.

View Article: PubMed Central - PubMed

Affiliation: School of Public Health and Community Medicine, Faculty of Medicine, University of New South Wales, Kensington, New South Wales, Australia.

ABSTRACT

Background: Using the COPD Diagnostic Questionnaire (CDQ) as a selection tool for spirometry could potentially improve the efficiency and accuracy of chronic obstructive pulmonary disease (COPD) diagnosis in at-risk patients.

Aim: To identify an optimal single cut point for the CDQ that divides primary care patients into low or high likelihood of COPD, with the latter group undergoing spirometry.

Methods: Former or current smokers aged 40-85 years with no prior COPD diagnosis were invited to a case-finding appointment with the practice nurse at various general practices in Sydney, Australia. The CDQ was collected and pre- and post-bronchodilator spirometry was performed. Cases with complete CDQ data and spirometry meeting quality standards were analysed (1,054 out of 1,631 patients). CDQ cut points were selected from a receiver operating characteristic (ROC) curve.

Results: The area under the ROC curve was 0.713. A cut point of 19.5 had the optimal combination of sensitivity (63%) and specificity (70%) with two-thirds below this cut point. A cut point of 14.5 corresponded to a sensitivity of 91%, specificity of 35% and negative predictive value of 96%, and 31% of patients below this cut point.

Conclusions: The CDQ can be used to select patients at risk of COPD for spirometry using one cut point. We consider two possible cut points. The 19.5 cut point excludes a higher proportion of patients from undergoing spirometry with the trade-off of more false negatives. The 14.5 cut point has a high sensitivity and negative predictive value, includes more potential COPD cases but has a higher rate of false positives.

Show MeSH
Related in: MedlinePlus