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Diagnostic accuracy of pre-bronchodilator FEV1/FEV6 from microspirometry to detect airflow obstruction in primary care: a randomised cross-sectional study.

van den Bemt L, Wouters BC, Grootens J, Denis J, Poels PJ, Schermer TR - NPJ Prim Care Respir Med (2014)

Bottom Line: A pre-BD FEV1/FEV6 value <0.73 as measured with the PiKo-6 microspirometer was compared with a post-BD FEV1/FVC (forced vital capacity) <0.70 and FEV1/FVC<lower limit of normal (LLN) from diagnostic spirometry.One hundred and four subjects were analysed (59.6% males, 42.3% current smokers).In all, 18% of positive microspirometry results were not confirmed by a post-BD FEV1/FVC <0.70 and 44% of tests were false positive compared with the LLN criterion for airflow obstruction.

View Article: PubMed Central - PubMed

Affiliation: Department of Primary and Community Care, Radboud University Medical Center, Nijmegen, The Netherlands.

ABSTRACT

Background: Forced expiratory volume in 1s/forced expiratory volume in 6 s ( FEV1/FEV6) assessment with a microspirometer may be useful in the diagnostic work up of subjects who are suspected of having COPD in primary care.

Aim: To determine the diagnostic accuracy of a negative pre-bronchodilator (BD) microspirometry test relative to a full diagnostic spirometry test in subjects in whom general practitioners (GPs) suspect airflow obstruction.

Methods: Cross-sectional study in which the order of microspirometry and diagnostic spirometry tests was randomised. Study subjects were (ex-)smokers aged ≥50 years referred for diagnostic spirometry to a primary care diagnostic centre by their GPs. A pre-BD FEV1/FEV6 value <0.73 as measured with the PiKo-6 microspirometer was compared with a post-BD FEV1/FVC (forced vital capacity) <0.70 and FEV1/FVC

Results: One hundred and four subjects were analysed (59.6% males, 42.3% current smokers). Negative predictive values from microspirometry for airflow obstruction based on the fixed and LLN cut-off points were 94.4% (95% confidence interval (CI), 86.4-98.5) and 96.3% (95% CI, 88.2-99.3), respectively. In all, 18% of positive microspirometry results were not confirmed by a post-BD FEV1/FVC <0.70 and 44% of tests were false positive compared with the LLN criterion for airflow obstruction.

Conclusions: Pre-bronchodilator microspirometry seems to be able to reliably preselect patients for further assessment of airflow obstruction by means of regular diagnostic spirometry. However, use of microspirometry alone would result in overestimation of airflow obstruction and should not replace regular spirometry when diagnosing COPD in primary care.

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Related in: MedlinePlus

Receiver operating characteristic (ROC) curve and its coordinates for the forced expiratory volume in 1 s /forced expiratory volume in 6 s (FEV1/FEV6) ratio using post-BD FEV1/FVC<0.7 as criterion for chronic airflow obstruction (AUC: 0.937).
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fig3: Receiver operating characteristic (ROC) curve and its coordinates for the forced expiratory volume in 1 s /forced expiratory volume in 6 s (FEV1/FEV6) ratio using post-BD FEV1/FVC<0.7 as criterion for chronic airflow obstruction (AUC: 0.937).

Mentions: Of the 54 subjects with a negative microspirometry test (i.e., pre-BD FEV1/FEV6 ⩾0.73), absence of airflow obstruction was confirmed by a negative diagnostic spirometric test (i.e., post-BD FEV1/FVC ⩾0.70) in 51 subjects (see Figure 2). Thus, the NPV was 94.4% (95% CI, 86.4–98.5). Table 2 shows the diagnostic test characteristics both (i.e., ⩾0.73 and ⩾LLN) for the diagnostic spirometry cut-off points and for the subgroup of subjects with a specific referral for suspected COPD. The NPV of pre-BD FEV1/FEV6 ⩾0.73 was high for both definitions of airflow obstruction but with 96.3% (95% CI, 88.2–99.3) slightly better for the LLN cut-off point. The NPV for subjects referred specifically for suspected COPD was 96.3% for both diagnostic spirometry cut-off points. Positive microspirometry tests were confirmed by positive diagnostic spirometry tests in only 82.0% (95% CI, 73.3–86.3) and 56.0% (95% CI, 47.3–59.3), respectively (see Table 2 for these positive predictive values and the results for specificity, sensitivity and Kappa). Figure 3 shows the receiver operating characteristic curve for different FEV1/FEV6 cut-off points. The area under the curve was 0.937.


Diagnostic accuracy of pre-bronchodilator FEV1/FEV6 from microspirometry to detect airflow obstruction in primary care: a randomised cross-sectional study.

van den Bemt L, Wouters BC, Grootens J, Denis J, Poels PJ, Schermer TR - NPJ Prim Care Respir Med (2014)

Receiver operating characteristic (ROC) curve and its coordinates for the forced expiratory volume in 1 s /forced expiratory volume in 6 s (FEV1/FEV6) ratio using post-BD FEV1/FVC<0.7 as criterion for chronic airflow obstruction (AUC: 0.937).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4373403&req=5

fig3: Receiver operating characteristic (ROC) curve and its coordinates for the forced expiratory volume in 1 s /forced expiratory volume in 6 s (FEV1/FEV6) ratio using post-BD FEV1/FVC<0.7 as criterion for chronic airflow obstruction (AUC: 0.937).
Mentions: Of the 54 subjects with a negative microspirometry test (i.e., pre-BD FEV1/FEV6 ⩾0.73), absence of airflow obstruction was confirmed by a negative diagnostic spirometric test (i.e., post-BD FEV1/FVC ⩾0.70) in 51 subjects (see Figure 2). Thus, the NPV was 94.4% (95% CI, 86.4–98.5). Table 2 shows the diagnostic test characteristics both (i.e., ⩾0.73 and ⩾LLN) for the diagnostic spirometry cut-off points and for the subgroup of subjects with a specific referral for suspected COPD. The NPV of pre-BD FEV1/FEV6 ⩾0.73 was high for both definitions of airflow obstruction but with 96.3% (95% CI, 88.2–99.3) slightly better for the LLN cut-off point. The NPV for subjects referred specifically for suspected COPD was 96.3% for both diagnostic spirometry cut-off points. Positive microspirometry tests were confirmed by positive diagnostic spirometry tests in only 82.0% (95% CI, 73.3–86.3) and 56.0% (95% CI, 47.3–59.3), respectively (see Table 2 for these positive predictive values and the results for specificity, sensitivity and Kappa). Figure 3 shows the receiver operating characteristic curve for different FEV1/FEV6 cut-off points. The area under the curve was 0.937.

Bottom Line: A pre-BD FEV1/FEV6 value <0.73 as measured with the PiKo-6 microspirometer was compared with a post-BD FEV1/FVC (forced vital capacity) <0.70 and FEV1/FVC<lower limit of normal (LLN) from diagnostic spirometry.One hundred and four subjects were analysed (59.6% males, 42.3% current smokers).In all, 18% of positive microspirometry results were not confirmed by a post-BD FEV1/FVC <0.70 and 44% of tests were false positive compared with the LLN criterion for airflow obstruction.

View Article: PubMed Central - PubMed

Affiliation: Department of Primary and Community Care, Radboud University Medical Center, Nijmegen, The Netherlands.

ABSTRACT

Background: Forced expiratory volume in 1s/forced expiratory volume in 6 s ( FEV1/FEV6) assessment with a microspirometer may be useful in the diagnostic work up of subjects who are suspected of having COPD in primary care.

Aim: To determine the diagnostic accuracy of a negative pre-bronchodilator (BD) microspirometry test relative to a full diagnostic spirometry test in subjects in whom general practitioners (GPs) suspect airflow obstruction.

Methods: Cross-sectional study in which the order of microspirometry and diagnostic spirometry tests was randomised. Study subjects were (ex-)smokers aged ≥50 years referred for diagnostic spirometry to a primary care diagnostic centre by their GPs. A pre-BD FEV1/FEV6 value <0.73 as measured with the PiKo-6 microspirometer was compared with a post-BD FEV1/FVC (forced vital capacity) <0.70 and FEV1/FVC

Results: One hundred and four subjects were analysed (59.6% males, 42.3% current smokers). Negative predictive values from microspirometry for airflow obstruction based on the fixed and LLN cut-off points were 94.4% (95% confidence interval (CI), 86.4-98.5) and 96.3% (95% CI, 88.2-99.3), respectively. In all, 18% of positive microspirometry results were not confirmed by a post-BD FEV1/FVC <0.70 and 44% of tests were false positive compared with the LLN criterion for airflow obstruction.

Conclusions: Pre-bronchodilator microspirometry seems to be able to reliably preselect patients for further assessment of airflow obstruction by means of regular diagnostic spirometry. However, use of microspirometry alone would result in overestimation of airflow obstruction and should not replace regular spirometry when diagnosing COPD in primary care.

Show MeSH
Related in: MedlinePlus