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Cut-off value of FEV 1 /FEV 6 as a surrogate for FEV 1 /FVC for detecting airway obstruction in a Korean population

View Article: PubMed Central - PubMed

ABSTRACT

Background: Forced expiratory volume in 1 second (FEV1)/forced expiratory volume in 6 seconds (FEV6) has been proposed as an alternative to FEV1/forced vital capacity (FVC) for detecting airway obstruction. A fixed cut-off value for FEV1/FEV6 in a Korean population is lacking. We investigated a fixed cut-off for FEV1/FEV6 as a surrogate for FEV1/FVC for detecting airway obstruction.

Materials and methods: We used data obtained in the 5 years of the Fifth and Sixth Korean National Health and Nutrition Examination Survey. A total of 14,978 participants aged ≥40 years who underwent spirometry adequately were the study cohort. “Airway obstruction” was a fixed cut-off FEV1/FVC <70% according to the Global Initiative for Chronic Obstructive Lung Disease guidelines. We also used European Respiratory Society/Global Lung Initiative 2012 equations for the FEV1/FVC lower limit of normal.

Results: Among the 14,978 participants (43.5% male, 56.5% female; mean age: 56.9 years for men and 57.0 years for women), 14.0% had obstructive lung function according to a fixed cut-off FEV1/FVC <70%. Optimal FEV1/FEV6 cut-off for predicting FEV1/FVC <70% was 75% using receiver operating characteristic curve analyses (area under receiver operating characteristic curve =0.989, 95% confidence interval 0.987–0.990). This fixed cut-off of FEV1/FEV6 showed 93.8% sensitivity, 94.8% specificity, 74.7% positive predictive value, 98.9% negative predictive value, and 0.8 Cohen’s kappa coefficient. When compared with FEV1/FVC < lower limit of normal, FEV1/FEV6 <75% tended to over-diagnose airflow limitation (just like a fixed cut-off of FEV1/FVC <70%). When grouped according to age and FEV1 (%), FEV1/FEV6 <75% diagnosed more airway obstruction in older participants and mild–moderate stages compared with FEV1/FVC <70%.

Conclusion: A valid fixed cut-off for detecting airway obstruction in a Korean population is FEV1/FEV6 of 75%, but should be used with caution in older individuals and those with mild–moderate airway obstruction.

No MeSH data available.


Related in: MedlinePlus

FEV1/FVC LLN, FEV1/FVC, FEV1/FEV6, and the mean difference between FEV1/FEV6 and FEV1/FVC according to the FEV1 (%) group.Notes: With increasing severity of obstruction, the mean difference between FEV1/FEV6 and FEV1/FVC was increasingly larger. The mean difference between FEV1/FVC LLN and FEV1/FEV6 was larger than the mean difference between FEV1/FVC LLN and FEV1/FVC at mild–moderate stages of airway obstruction, but was smaller at severe and very severe stages.Abbreviations: FEV1, forced expiratory volume in 1 second; FEV6, forced expiratory volume in 6 seconds; FVC, forced vital capacity; LLN, lower limit of normal.
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f3-copd-11-1957: FEV1/FVC LLN, FEV1/FVC, FEV1/FEV6, and the mean difference between FEV1/FEV6 and FEV1/FVC according to the FEV1 (%) group.Notes: With increasing severity of obstruction, the mean difference between FEV1/FEV6 and FEV1/FVC was increasingly larger. The mean difference between FEV1/FVC LLN and FEV1/FEV6 was larger than the mean difference between FEV1/FVC LLN and FEV1/FVC at mild–moderate stages of airway obstruction, but was smaller at severe and very severe stages.Abbreviations: FEV1, forced expiratory volume in 1 second; FEV6, forced expiratory volume in 6 seconds; FVC, forced vital capacity; LLN, lower limit of normal.

Mentions: However, with increasing age, the mean difference between FEV1/FVC LLN and FEV1/FVC or FEV1/FEV6 showed only a slight difference. With increasing severity of obstruction, the mean difference between FEV1/FVC LLN and FEV1/FEV6 was larger than the mean difference between FEV1/FVC LLN and FEV1/FVC at mild–moderate stages of airway obstruction, but that was smaller than that at severe and very severe stages (Figures 2 and 3).


Cut-off value of FEV 1 /FEV 6 as a surrogate for FEV 1 /FVC for detecting airway obstruction in a Korean population
FEV1/FVC LLN, FEV1/FVC, FEV1/FEV6, and the mean difference between FEV1/FEV6 and FEV1/FVC according to the FEV1 (%) group.Notes: With increasing severity of obstruction, the mean difference between FEV1/FEV6 and FEV1/FVC was increasingly larger. The mean difference between FEV1/FVC LLN and FEV1/FEV6 was larger than the mean difference between FEV1/FVC LLN and FEV1/FVC at mild–moderate stages of airway obstruction, but was smaller at severe and very severe stages.Abbreviations: FEV1, forced expiratory volume in 1 second; FEV6, forced expiratory volume in 6 seconds; FVC, forced vital capacity; LLN, lower limit of normal.
© Copyright Policy
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4998021&req=5

f3-copd-11-1957: FEV1/FVC LLN, FEV1/FVC, FEV1/FEV6, and the mean difference between FEV1/FEV6 and FEV1/FVC according to the FEV1 (%) group.Notes: With increasing severity of obstruction, the mean difference between FEV1/FEV6 and FEV1/FVC was increasingly larger. The mean difference between FEV1/FVC LLN and FEV1/FEV6 was larger than the mean difference between FEV1/FVC LLN and FEV1/FVC at mild–moderate stages of airway obstruction, but was smaller at severe and very severe stages.Abbreviations: FEV1, forced expiratory volume in 1 second; FEV6, forced expiratory volume in 6 seconds; FVC, forced vital capacity; LLN, lower limit of normal.
Mentions: However, with increasing age, the mean difference between FEV1/FVC LLN and FEV1/FVC or FEV1/FEV6 showed only a slight difference. With increasing severity of obstruction, the mean difference between FEV1/FVC LLN and FEV1/FEV6 was larger than the mean difference between FEV1/FVC LLN and FEV1/FVC at mild–moderate stages of airway obstruction, but that was smaller than that at severe and very severe stages (Figures 2 and 3).

View Article: PubMed Central - PubMed

ABSTRACT

Background: Forced expiratory volume in 1 second (FEV1)/forced expiratory volume in 6 seconds (FEV6) has been proposed as an alternative to FEV1/forced vital capacity (FVC) for detecting airway obstruction. A fixed cut-off value for FEV1/FEV6 in a Korean population is lacking. We investigated a fixed cut-off for FEV1/FEV6 as a surrogate for FEV1/FVC for detecting airway obstruction.

Materials and methods: We used data obtained in the 5 years of the Fifth and Sixth Korean National Health and Nutrition Examination Survey. A total of 14,978 participants aged ≥40 years who underwent spirometry adequately were the study cohort. “Airway obstruction” was a fixed cut-off FEV1/FVC <70% according to the Global Initiative for Chronic Obstructive Lung Disease guidelines. We also used European Respiratory Society/Global Lung Initiative 2012 equations for the FEV1/FVC lower limit of normal.

Results: Among the 14,978 participants (43.5% male, 56.5% female; mean age: 56.9 years for men and 57.0 years for women), 14.0% had obstructive lung function according to a fixed cut-off FEV1/FVC <70%. Optimal FEV1/FEV6 cut-off for predicting FEV1/FVC <70% was 75% using receiver operating characteristic curve analyses (area under receiver operating characteristic curve =0.989, 95% confidence interval 0.987–0.990). This fixed cut-off of FEV1/FEV6 showed 93.8% sensitivity, 94.8% specificity, 74.7% positive predictive value, 98.9% negative predictive value, and 0.8 Cohen’s kappa coefficient. When compared with FEV1/FVC < lower limit of normal, FEV1/FEV6 <75% tended to over-diagnose airflow limitation (just like a fixed cut-off of FEV1/FVC <70%). When grouped according to age and FEV1 (%), FEV1/FEV6 <75% diagnosed more airway obstruction in older participants and mild–moderate stages compared with FEV1/FVC <70%.

Conclusion: A valid fixed cut-off for detecting airway obstruction in a Korean population is FEV1/FEV6 of 75%, but should be used with caution in older individuals and those with mild–moderate airway obstruction.

No MeSH data available.


Related in: MedlinePlus