Avaliação do desempenho diagnóstico do questionário Global Initiative for Asthma (GINA) para detecção de asma induzida pelo exercício em pacientes com asma

Abstract

INTRODUCTION: Exercise-induced asthma (EIA) is defined as transient airway obstruction during and after exercise and may be evidenced by a decrease in forced expiratory volume in the first second (FEV1). Although several instruments have been designed and tested to detect EIA, most have low diagnostic power. Thus, considering the wide use of the Global Initiative for Asthma (GINA) in clinical practice and that it has a specific question for physical activity, it is relevant to evaluate its performance in the detection of EIA. OBJECTIVES: To evaluate the diagnostic performance of the physical activity related question of GINA in the detection of EIA in children and adolescents with asthma. METHODS: This is a cross-sectional, observational, study performed in the Laboratory of Pediatric Physical Activity. Children and adolescents (6 to 18 years old) with clinical diagnosis of asthma were included. Patients with signs of pulmonary exacerbation and those with motor limitations were excluded. Patients were divided into 2 groups according to severity classification: mild/moderate asthma (MMA) and severe therapy-resistant asthma (STRA). Both the assessment of severity and disease control followed GINA criteria. Anthropometric and clinical data were collected. In addition, pulmonary function was evaluated and the exercise-induced bronchoprovocation test (EIB) was performed. The EIB test was performed on a treadmill, with increases in speed and inclination, in accordance with international recommendations. We have used the fourth question of GINA (Any activity limitation due to asthma?) to evaluate the diagnostic power of the instrument. For statistical purposes, the comparisons were performed using the Student t test and the Pearson's chi-square test. The analysis of the diagnostic performance of the GINA questionnaire specific question for the detection of EIB was evaluated using the ROC curve. The study was approved by the Research Ethics Committee and all parents and/or guardians signed a free and informed consent form and the participants the study assent term. RESULTS: We have evaluated 40 patients, 17 of the MMA group and 23 of the STRA group. The mean age was 11.25 years, with a FEV1 (z-score) of 0.33 and 32.5% classified as uncontrolled disease. Of these, 19 (47.5%) presented a decrease in FEV1 in the EIB test, 13 (56.5%) in the STRA group and 6 (35.2%) in the MMA group. There was a significantly higher EIA frequency (p=0.05) in subjects with lower FEV1 (z-score <-1.0) compared to those with z-score >-1.0. However, there were no significant differences in the frequency of EIB when evaluating the influence of disease severity and control. Likewise, no association of question 4 of GINA was found with the EIA results (p>0.05). The sensitivity found was 57.9% and the specificity was 57.1% (n=40). The area under the ROC curve did not demonstrate a discriminative power of the fourth GINA question for the detection of EIA in children and adolescents with asthma (p=0.35). CONCLUSION: The results of the present study demonstrated that the fourth question of the GINA questionnaire (physical activity) has a clinically insufficient diagnostic power for the detection of EIA in children and adolescents with asthma (MMA and STRA). Thus, it is recommended that the evaluation of EIA to be performed by the EIB test, avoiding underestimation and/or overestimation resulting from this evaluation.