RESULTS
Between January 2017 and December 2019, spirometries were performed on 470 children under 15 years of age with clinical suspicion of asthma at the INDISA Clinic. Of these, 416 children had spirometry plus MT and/or ET performed in an interval of less than 2 months. Among the reports of this group studied, there were 6 spirometries with obstructive report without SRBD in FEV1, 17 obstructive reports with SBDR in FEV1, 38 normal with SRBD in FEV1 and the vast majority, 355, with normal spirometry without SBDR in FEV1. In this last group, 324 spirometries showed a variation in FVC between the pre- and post-bronchodilator value of less than 5%. Figure 1 details the flowchart of pulmonary function tests.
The mean age of the children was 9.04 years (SD: 2.67 years; Range: 5 – 15 years), and 56.17% were boys. In 37.04% the use of corticosteroids was reported, 33.02% were not using it and in 29.94% it was not possible to obtain that information. The detail of the socio-demographic and clinical information of the patients is shown in Table 1.
194 children underwent MT, 224 ET, and 94 had records of both tests.
The MT was positive (PC20 < 8 mg/dl) in 135 children (69.6%), of which 103 (53.1%) had a PC20 ≤ 2 mg/dl. The ET had a positivity of 11.6% (26 of 224 children).
Of the 42 children with SBDR in FEF25-75 and TM performed, 28 had a PC20 ≤ 2 mg/dl; in 7 a PC20 between 2 and 8 mg/dl; and in another 7, a PC20 > 8 mg/dl.
Similarly, of the 152 children without SBDR in FEF25-75and MT performed, 75 had a PC20 ≤ 2mg/dl; in 25 between 2 and 8 mg/dl; and in 52 > 8 mg/dl.
On the other hand, among the children who presented negative MT (91), 14 (15.4%) showed an SBDR in FEF25-75 in the spirometry previously performed.
Figure 2 shows the positivity to MT and/or ET, between the comparison groups according to the presence or absence of SBDR in the FEF25-75. When applying the chi-square test, it was found that this difference was statistically significant between both comparison groups (p value = 0.0396).