This Article Full Text Full Text (PDF) All Versions of this Article: 200604-517OCv1 174/5/493    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Hansen, J. E. Articles by Wasserman, K. Search for Related Content PubMed PubMed Citation Articles by Hansen, J. E. Articles by Wasserman, K.

Ethnic- and Sex-free Formulae for Detection of Airway Obstruction

Division of Respiratory and Critical Care Physiology and Medicine, Department of Medicine, Los Angeles Biomedical Institute at Harbor–UCLA Medical Center, Torrance, California

Correspondence and requests for reprints should be addressed to James E. Hansen, M.D., Box 405, Harbor-UCLA Medical Center, Torrance, CA 90509. E-mail: jhansen{at}labiomed.org

Rationale: Spirometric detection of airway obstruction in adults requires separate predictive formulae for each ethnicity and sex for percentage of FEV₁/FVC (%FEV₁/FVC) and percentage of FEV₃/FVC (%FEV₃/FVC), the major measurements for defining airway obstruction.

Objectives: To eliminate the need for multiple formulae for black, Latin, and white men and women by developing single formulae with less variance than current formulae for %FEV₁/FVC and %FEV₃/FVC.

Methods: Data from nearly 6,000 healthy never-smokers 20.0–79.9 yr of age in the Third National Health and Nutrition Examination Survey were reevaluated mathematically and graphically based on the preliminary hypothesis that predictive normal FEV₁/FVC and FEV₃/FVC ratios could be calculated from the age and FVC alone, without considering ethnicity, sex, or height. Current and new formulae were evaluated, first considering the population as consisting of 36 equally weighted subgroups (6 decades x 3 ethnicities x 2 sexes) and then weighting each individual equally.

Measurements and Results: For each year of age, the slope of %FEV₁/FVC versus FVC approximated –1.8%/l/yr; the slope of %FEV₃/FVC versus FVC approximated –0.8%/l/yr. After trial and error iterations, the optimal formulae were %FEV₁/FVC = 98.8 – 0.25 x years – 1.79 x FVC and %FEV₃/FVC = 105.4 – 0.20 x years – 0.75 x FVC.

Conclusions: These two new predicting formulae for %FEV₁/FVC and %FEV₃/FVC, which require only age and FVC as variables, approximate actual values closer than previously published separate formulae for each ethnicity and sex. With 95% confidence limits, they should allow better discrimination between normality and airway obstruction in adults of at least these three ethnicities.

Key Words: FEV₁ • FEV₃ • FVC • reference values • spirometry

This article has been cited by other articles:

				W. C. Moore and S. P. Peters Update in Asthma 2006 Am. J. Respir. Crit. Care Med., April 1, 2007; 175(7): 649 - 654. [Full Text] [PDF]