MATERIAL AND METHOD
A cross-sectional study with an analytical component was carried out,
without direct intervention on the study subjects.
The study population was children aged 5 to 15 years with clinical
suspicion of asthma, who underwent spirometry and MT or ET within a
period of 60 days, in the pulmonary function laboratory of Clínica
INDISA, from January 2017 to December 2019.
Spirometry was performed according to national and international
standards, with an MGC Diagnostics ® equipment, and only those that met
the acceptability and reproducibility criteria were included(12,13). Multiethnic reference values were used for
their interpretation (14). The MT was carried out with
the technique of increasing concentrations of Cockcroft and the PC20(5,15) was determined. The ET was performed on a
treadmill at submaximal heart rate, with humidity and environmental
temperature control, with subsequent measurement of the percentages of
fall in FEV1 with respect to baseline at 3, 5, 10, and
15 minutes post-exercise (16).
We worked on an anonymized database, which identified each child with a
number (ID), age (in years, months) and if he was using inhaled
corticosteroids at the time of the exam, height, weight, clinical
diagnosis, and date performance of spirometry, MT and TE. The lower
limit (LI) and Zscore of FEV1, FEV1/FVC,
FVC, FEF25-75, % change with the bronchodilator in
FEV1, FEF25-75 and FVC were recorded
from the spirometries. The PC20 and the percentage of maximum drop in
FEV1 in the ET were verified.
All these data from the reports of these tests appear in the manual and
computerized records of the Clínica INDISA lung function laboratory.
Children who obtained a bronchodilator response (BDR) ≥ 30% in
FEF25-75 (SBDR) were compared versus those who obtained
a BDR < 30% with normal FEV1,
FEV1/FVC, in relation to the MT and ET in each patient.
The STATA 14.0 statistical package and Microsoft Excel 2016 software
were used for data analysis. A descriptive analysis of the variables of
interest was made and Chi-square tests were used to analyze the groups
in relation to their results in the MT and ET. A p value less than 0.05
was considered statistically significant.
To carry out this project, authorization was obtained from the Medical
Directory of the Clínica INDISA and the approval of the Bioethics
Committee of the Andrés Bello University.