|Author||Boys N=2492||Girls N=2072|
Airway obstruction in sick children and adolescents
Applying predicted values for FEV1/FVC according to various authors on data from paediatric patients from the Children’s Hospital of Pittsburgh (courtesy Dr. Weiner) discloses differences in the prevalence rate of airway obstruction in boys, less so in girls (see table).
Airway obstruction in adult patients
Data from with a wide range of diagnoses from two hospitals in Australia and one in Poland disclosed the following trend (see figure below). There is fair agreement in the prevalence rate of airway obstruction according to GLI-2012  and NHANES  predicted values, with NHANES in women producing a systematically higher prevalence rate. The ECSC/ERS  prediction equations lead to a somewhat lower prevalence rate in males up to 60 year, and in young females (see figure). In general differences are relatively small; hence adoption of the Quanjer GLI-2012 equations will not lead to a clinically significant change in the prevalence rate of airway obstruction.
As explained earlier  stage 1 is not regarded as representing lung disease. Therefore the analysis is limited to GOLD stages 2-4. The prevalence rate of GOLD stages 2-4 has the same pattern as previously published for GOLD stage 1: under diagnosis (~20%) of airway obstruction up to age 55-60 year, and over diagnosis (~20%) above that age. These percentages agree with those reported in an earlier clinical study . This indicates that an age-related bias even affects GOLD stage 2. This is in part due to the fact that the FEV1 should be < 80% of the predicted value. We concluded earlier that not only FEV1/FVC < 0.70, but also FEV1 < 80%, was associated with a strong age-related bias.
|Percentage of patients with airway obstruction (FEV1/FVC < LLN) based on Quanjer GLI-2012, Hankinson (NHANES), GOLD guidelines and ECSC/ERS predicted values.|
- Quanjer PH, Stanojevic S, Cole TJ, et al. and the ERS Global Lung Function Initiative. Multi-ethnic reference values for spirometry for the 3-95 years age range: the Global Lung Function 2012 equations. Eur Respir J 2012; 40: 1324-1343. PubMed
- Hankinson JL, Odencrantz JR, Fedan KB. Spirometric reference values from a sample of the general US population. Am J Respir Crit Care Med 1995; 152: 179–187. Manuscript
- Quanjer PH, Tammeling GJ, Cotes JE, Pedersen OF, Peslin R, Yernault J-C. Lung volume and forced ventilatory flows. Report Working Party Standardization of Lung Function Tests, European Community for Steel and Coal. Official Statement of the European Respiratory Society. Eur Respir J 1993; 6: Suppl. 16, 5–40. Erratum Eur Respir J 1995; 8: 1629.
- Miller MR, Quanjer PH, Swanney MP, Ruppel G, Enright PL. Interpreting lung function data using 80% predicted and fixed thresholds misclassifies more than 20% of patients. Chest 2011; 139: 52-59. Manuscript
Acknowledgement: Figures modified and reproduced with permission of the European Respiratory Society. Eur Respir J 2013; in press; doi: 10.1183/09031936.00195512.