A27-03 Clinical Validation of GLI-2012 Spirometry Reference Values in 3-11 Year Old Italian Children

Abstract Background We previously reported a statistically significant difference between GLI-2012 spirometry reference values 1 and spirometry indices obtained in healthy children from northern and central Italy 2. In the present study we aimed to evaluate whether this difference was significantly relevant in children referred to our ambulatory. Methods - Reference equations were calculated by linear regression using spirometry data previously obtained in 404 healthy children aged 3.2-11.5 years in Florence and Udine, Italy 2. The GLI-2012 reference equations 1 were compared with our reference equations in children consecutively referred to our ambulatory in Florence because of a history of cough or wheezing. For GLI-2012, all spirometry indices were considered to be abnormal if the Z-score was -1.64; when using our reference values, the Forced Expiratory Volume in 1 second (FEV1) was considered to be abnormal if the Z-score was -1.64, while for the FEV1/Forced Vital Capacity (FEV1/FVC) ratio a value lower than 82% (corresponding to the 5th centile in our healthy children) was considered to be abnormal. Results - A total of 92 children aged 4.3-11.9 years referred to our ambulatory underwent spirometry. FEV1 was found to be abnormal in 15 children when using our reference equations, while only 5 children had abnormal FEV1 when using GLI-2012, and 2 children had abnormal FEV1 with GLI-2012 but not with our reference equations (p = 0.001 by Fisher’s exact test). Similarly, FEV1/FVC was abnormal in 15 children with GLI-2012 and in 24 children with our reference values (Fig.), and none of the children with normal FEV1/FVC with our reference values resulted abnormal with GLI-2012 (p 0.001 by Fisher’s exact test). Conclusions - The GLI-2012 reference equations for spirometry may underestimate disease in the Italian pediatric population. 1 Eur Respir J 2012;40:1324-1343. 2 Am J Respir Crit Care Med 2019;199:A7448. This abstract is funded by: Meyer Children’s Hospital IRCCS