FEV1/FVC ratio of 70% misclassifies patients with obstruction at the extremes of age

Scott D. Roberts, Mark O. Farber, Kenneth S Knox, Gary S. Phillips, Nitin Y. Bhatt, John G. Mastronarde, Karen L. Wood

Research output: Contribution to journalArticle

103 Citations (Scopus)

Abstract

Background: The American Thoracic Society recommends using the lower limit of normal (LLN) method to diagnose obstructive lung disease. However, few studies have investigated the clinical relevance of these recommendations. We compared the LLN derived from available data sets to a fixed ratio (FEV 1/FVC, < 75% or 70%) and also to the FEV1/FVC percent predicted ratio to determine the impact of changing the FEV1/FVC "cutoff" on the spirometric diagnosis of obstructive lung disease. Methods: FEV1, FVC, FEV1/FVC ratio, age, race, sex, height, and weight were recorded from 1,503 pulmonary function tests. Predicted values were calculated using the Third National Health and Nutrition Examination Study data set (Hankinson), and reference values from studies by Crapo, Knudson, and Morris. In addition, the LLN of the FEV1/FVC ratio was calculated for the Hankinson and Crapo reference values. Results: The number of studies interpreted as obstructed varied from 37% using the Hankinson data set to 55% using the 75% fixed ratio method. Comparing the LLN method vs the 70% fixed ratio method resulted in 7.5% (Hankinson LLN vs 70% fixed) and 6.9% (Crapo LLN vs 70% fixed), which were discordant results. Age was the strongest predictor of discordance, and 16% of subjects > 74 years of age had discordant results comparing Hankinson values to the 70% fixed method. Conclusion: At the extremes of age and height, a large number of spirometry test results will be interpreted as showing an obstructive defect if a 70% fixed ratio method is used for interpretation compared with the LLN derived from the Hankinson data set.

Original languageEnglish (US)
Pages (from-to)200-206
Number of pages7
JournalChest
Volume130
Issue number1
DOIs
StatePublished - Jul 2006
Externally publishedYes

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Obstructive Lung Diseases
Spirometry
Datasets

Keywords

  • Airway obstruction
  • Lower limit of normal
  • Pulmonary function testing
  • Spirometry

ASJC Scopus subject areas

  • Pulmonary and Respiratory Medicine

Cite this

Roberts, S. D., Farber, M. O., Knox, K. S., Phillips, G. S., Bhatt, N. Y., Mastronarde, J. G., & Wood, K. L. (2006). FEV1/FVC ratio of 70% misclassifies patients with obstruction at the extremes of age. Chest, 130(1), 200-206. https://doi.org/10.1378/chest.130.1.200

FEV1/FVC ratio of 70% misclassifies patients with obstruction at the extremes of age. / Roberts, Scott D.; Farber, Mark O.; Knox, Kenneth S; Phillips, Gary S.; Bhatt, Nitin Y.; Mastronarde, John G.; Wood, Karen L.

In: Chest, Vol. 130, No. 1, 07.2006, p. 200-206.

Research output: Contribution to journalArticle

Roberts, SD, Farber, MO, Knox, KS, Phillips, GS, Bhatt, NY, Mastronarde, JG & Wood, KL 2006, 'FEV1/FVC ratio of 70% misclassifies patients with obstruction at the extremes of age', Chest, vol. 130, no. 1, pp. 200-206. https://doi.org/10.1378/chest.130.1.200
Roberts SD, Farber MO, Knox KS, Phillips GS, Bhatt NY, Mastronarde JG et al. FEV1/FVC ratio of 70% misclassifies patients with obstruction at the extremes of age. Chest. 2006 Jul;130(1):200-206. https://doi.org/10.1378/chest.130.1.200
Roberts, Scott D. ; Farber, Mark O. ; Knox, Kenneth S ; Phillips, Gary S. ; Bhatt, Nitin Y. ; Mastronarde, John G. ; Wood, Karen L. / FEV1/FVC ratio of 70% misclassifies patients with obstruction at the extremes of age. In: Chest. 2006 ; Vol. 130, No. 1. pp. 200-206.
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abstract = "Background: The American Thoracic Society recommends using the lower limit of normal (LLN) method to diagnose obstructive lung disease. However, few studies have investigated the clinical relevance of these recommendations. We compared the LLN derived from available data sets to a fixed ratio (FEV 1/FVC, < 75{\%} or 70{\%}) and also to the FEV1/FVC percent predicted ratio to determine the impact of changing the FEV1/FVC {"}cutoff{"} on the spirometric diagnosis of obstructive lung disease. Methods: FEV1, FVC, FEV1/FVC ratio, age, race, sex, height, and weight were recorded from 1,503 pulmonary function tests. Predicted values were calculated using the Third National Health and Nutrition Examination Study data set (Hankinson), and reference values from studies by Crapo, Knudson, and Morris. In addition, the LLN of the FEV1/FVC ratio was calculated for the Hankinson and Crapo reference values. Results: The number of studies interpreted as obstructed varied from 37{\%} using the Hankinson data set to 55{\%} using the 75{\%} fixed ratio method. Comparing the LLN method vs the 70{\%} fixed ratio method resulted in 7.5{\%} (Hankinson LLN vs 70{\%} fixed) and 6.9{\%} (Crapo LLN vs 70{\%} fixed), which were discordant results. Age was the strongest predictor of discordance, and 16{\%} of subjects > 74 years of age had discordant results comparing Hankinson values to the 70{\%} fixed method. Conclusion: At the extremes of age and height, a large number of spirometry test results will be interpreted as showing an obstructive defect if a 70{\%} fixed ratio method is used for interpretation compared with the LLN derived from the Hankinson data set.",
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T1 - FEV1/FVC ratio of 70% misclassifies patients with obstruction at the extremes of age

AU - Roberts, Scott D.

AU - Farber, Mark O.

AU - Knox, Kenneth S

AU - Phillips, Gary S.

AU - Bhatt, Nitin Y.

AU - Mastronarde, John G.

AU - Wood, Karen L.

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N2 - Background: The American Thoracic Society recommends using the lower limit of normal (LLN) method to diagnose obstructive lung disease. However, few studies have investigated the clinical relevance of these recommendations. We compared the LLN derived from available data sets to a fixed ratio (FEV 1/FVC, < 75% or 70%) and also to the FEV1/FVC percent predicted ratio to determine the impact of changing the FEV1/FVC "cutoff" on the spirometric diagnosis of obstructive lung disease. Methods: FEV1, FVC, FEV1/FVC ratio, age, race, sex, height, and weight were recorded from 1,503 pulmonary function tests. Predicted values were calculated using the Third National Health and Nutrition Examination Study data set (Hankinson), and reference values from studies by Crapo, Knudson, and Morris. In addition, the LLN of the FEV1/FVC ratio was calculated for the Hankinson and Crapo reference values. Results: The number of studies interpreted as obstructed varied from 37% using the Hankinson data set to 55% using the 75% fixed ratio method. Comparing the LLN method vs the 70% fixed ratio method resulted in 7.5% (Hankinson LLN vs 70% fixed) and 6.9% (Crapo LLN vs 70% fixed), which were discordant results. Age was the strongest predictor of discordance, and 16% of subjects > 74 years of age had discordant results comparing Hankinson values to the 70% fixed method. Conclusion: At the extremes of age and height, a large number of spirometry test results will be interpreted as showing an obstructive defect if a 70% fixed ratio method is used for interpretation compared with the LLN derived from the Hankinson data set.

AB - Background: The American Thoracic Society recommends using the lower limit of normal (LLN) method to diagnose obstructive lung disease. However, few studies have investigated the clinical relevance of these recommendations. We compared the LLN derived from available data sets to a fixed ratio (FEV 1/FVC, < 75% or 70%) and also to the FEV1/FVC percent predicted ratio to determine the impact of changing the FEV1/FVC "cutoff" on the spirometric diagnosis of obstructive lung disease. Methods: FEV1, FVC, FEV1/FVC ratio, age, race, sex, height, and weight were recorded from 1,503 pulmonary function tests. Predicted values were calculated using the Third National Health and Nutrition Examination Study data set (Hankinson), and reference values from studies by Crapo, Knudson, and Morris. In addition, the LLN of the FEV1/FVC ratio was calculated for the Hankinson and Crapo reference values. Results: The number of studies interpreted as obstructed varied from 37% using the Hankinson data set to 55% using the 75% fixed ratio method. Comparing the LLN method vs the 70% fixed ratio method resulted in 7.5% (Hankinson LLN vs 70% fixed) and 6.9% (Crapo LLN vs 70% fixed), which were discordant results. Age was the strongest predictor of discordance, and 16% of subjects > 74 years of age had discordant results comparing Hankinson values to the 70% fixed method. Conclusion: At the extremes of age and height, a large number of spirometry test results will be interpreted as showing an obstructive defect if a 70% fixed ratio method is used for interpretation compared with the LLN derived from the Hankinson data set.

KW - Airway obstruction

KW - Lower limit of normal

KW - Pulmonary function testing

KW - Spirometry

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