Results
Of the 445 asthmatic children initially included, 42 were excluded (9
preschoolers and 2 schoolchildren did not perform properly the IOS, and
41 patients did not sign the consent); therefore, 403 (88.6%) asthmatic
were included, the mean age was 8.9 years, 57.1% were males, and 22.6%
were preschoolers, 59% schoolchildren, and 18.4% adolescents. The
severity of asthma according to GINA was 28.3% mildly persistent,
63.8% moderately persistent, and 7.9% severely persistent, and 32.5%
were atopic according to the SPT.
Among the demographic characteristics by age category, the presence of
an inversion of the reactance curve and the X5 approx. correction is
shown in Table 1. The schoolchildren and adolescents with X5 approx.
were older, and schoolchildren with X5 approx. were shorter than those
without X5 approx. The prevalence of atopy, asthma severity, and use of
controller therapy were similar between children with and without X5
approx. correction, by age category. A total of 264 children (65.5%)
presented an inversion of the reactance curve and correction of X5 to X5
approx. Patients that required an X5 correction showed a significant
lineal tendency by age category (Figure 2).
The percentage of abnormal values in R5, Fes, AX, and D5-20 was
significantly higher among preschoolers and schoolchildren who exhibited
an inversion of the reactance curve. However, only abnormal values of
D5-20 were found among adolescents with an inversion of the reactance
curve (Table 2). The mean of all the IOS parameters was significantly
higher in children with X5 approx. for all age categories, while the
mean of the spirometry parameter (FEF25-75%) was
significantly higher in children with X5 approx. for schoolchildren and
adolescents (Table 3).
The correlation of X5 approx. with all the IOS parameters and the
FEF25-75% was higher than the correlation of X5. The
correlation of X5 approx. with AX and D5-20 was strongly negative in
adolescents and with D5-20 in preschoolers. The correlation of X5
approx. was considerably negative with R5 and Fres in adolescents, with
R5, AX, and D5-20 in schoolchildren, and with R5 and AX in preschoolers
(Table 4).