Objective: To determine the interpretative consequences of adopting the Global Lungs 2012 (GLI-2012) spirometric prediction equations in a pediatric hospital population.
Material: Spirometric records from 2,192 white boys and 1,842 white girls, and 412 and 334 African-American boys and girls, respectively, aged 6.0-18.0 years, treated mainly for asthma, cystic fibrosis, cough, and dyspnoea.
Methods: Predicted values and lower limits of normal were calculated for FEV1, FVC, and FEV1/FVC, using prediction equations from GLI-2012, Hankinson, Knudson, Polgar, Wang, and Zapletal. Obstruction was defined as FEV1/FVC < LLN, a restrictive pattern as FEV1/FVC > LLN and FVC < LLN.
Results: There was good agreement for predicted values for FEV1, FVC, and FEV1/FVC from GLI-2012, Hankinson and Wang equations within ethnic groups. A near normal FEV1 but above normal FVC contributed to a low FEV1/FVC, particularly in African-Americans. Polgar, Knudson, and Zapletal predicteds produced disparate results. A restrictive pattern occurred in 2.2-11.2% of cases, with no statistical difference between GLI-2012 and Hankinson.
Conclusions: Transition from Hankinson and Wang equations to GLI-2012 leads to grossly similar prevalence rates of abnormally low values for FEV1, FVC, and FEV1/FVC, unlike equations from Knudson, Polgar, and Zapletal.
Keywords: airway obstruction; interpretive strategy; misclassification; reference equations; spirometry.
© 2013 Wiley Periodicals, Inc.