Impulse oscillometry in preschool children with persistent asthma can predict spirometry at school age

Abstract

Background: Lung function in children with persistent asthma may be impaired during preschool and school ages. The aim of this study was to describe if some preschool impulse oscillometry (IOS) parameters are related to spirometry alterations on reaching school age.Methods: In 66 diagnosed with persistent asthma, an IOS was performed at entrance and followed-up to school age where a spirometry was done. Results:The mean age was 4.9 years at the first evaluation and 7.9 years at the second evaluation, and 59.1% were male. During preschool, R5, R20, Fres, AX, and D5−20 were found to have diagnostic accuracy (area under the curve > 0.7) for predicting abnormal spirometry during school age (defined as FEV1 and/or FEV/FVC and/or FVC values below the lower limit of normality according to Quanjer predictive values). AX, D5−20, and R5 had the best LR+ to increase the probability of abnormal spirometry (50, 10, and 7.1, respectively). R20, R5, and AX was the best IOS parameters for discriminating bronchodilator response (BDR) in schoolchildren (LR+ = 3.4, 2.9, and 2.8, respectively). Conclusion:The findings of this study indicate that some IOS parameters between 3 and 5 years of age are useful for predicting abnormal spirometry and BDR at school age.

Impulse oscillometry at preschool age predicts lung function by spirometry at school age

“…The Chilean study, 1 in line with the two Finnish studies, 2,3 confirmed that IOS at preschool age in asthmatics was able to identify those patients who later had reduced FVS. Our postbronchiolitis cohort study 4 showed similar results in nonasthmatics, who constituted the great majority, 87% to 88%, of the cases at 6.2 and 12.3 years follow‐up visits.…”

“…The appropriate LR+ limits are dependent on the pretest probability, which depends on the severity of cases. In the study of Grell et al 1 all children had persistent asthma. The authors do not report the associations between IOS and post‐BD FVS parameters, but LR+ values for pre‐BD parameters were so high, that probably, the conclusions would have been similar.…”

“…In the current issue of Pediatric Pulmonology, Alberto Grell et al from Santiago, Chile, publish their interesting results on impulse oscillometry (IOS) at preschool age compared to flow‐volume spirometry (FVS) at school age in 66 children with persistent asthma 1 . When measured at the mean age of 4.9 years, respiratory system resistance at 5 Hz (R5), resonance frequency (Fres), reactance area (AX) and the difference between resistance at 5 and 20 Hz (D5‐20) were significant predictors of reduced forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and/or FEV1/FVC 3 years later, at the mean age of 7.9 years 1 . The parameters were analyzed also as categorized by limits obtained from international references.…”

“…Increased AX, D5‐20 and R5 had the highest positive likelihood ratios (LR+) of 50, 10, and 7.1, respectively, for reduced FEV1, FVC, and/or FEV/FVC 1 . Increased R20, R5, and AX were the best predictors for 10% FEV1 rises after bronchodilation (BD), LR+s being 3.4, 2.9 and 2.8, respectively 1 . Roughly, LR+ >5 means, LR+ 3–5 may mean and LR+ <3 does not mean a clinically significant change from the pretest to the posttest probability.…”

“…The parameters were analyzed also as categorized by limits obtained from international references. Increased AX, D5‐20 and R5 had the highest positive likelihood ratios (LR+) of 50, 10, and 7.1, respectively, for reduced FEV1, FVC, and/or FEV/FVC 1 . Increased R20, R5, and AX were the best predictors for 10% FEV1 rises after bronchodilation (BD), LR+s being 3.4, 2.9 and 2.8, respectively 1 .…”