A comparative study of bronchodilator reversibility with albuterol, between asthma symptomatic and asymptomatic children according to ISAAC questionnaire in Mexico City.

BACKGROUND Asthma is an important childhood disease. Recent surveys of the International Study of Asthma and Allergies in Childhood (ISAAC) suggest that the prevalence of asthma is increasing but these surveys do not include any pulmonary tests to confirm the possible diagnosis of asthma. OBJECTIVE To compare bronchodilator reversibility with the albuterol test in symptomatic and asymptomatic 6-7-year-old children with asthma participating in the ISAAC survey and living in Mexico City. PATIENTS AND METHODS We performed an observational, descriptive, comparative, cross sectional study in children participating in phase 3b of the ISAAC study. According to the ISAAC questionnaire children were classified as asthma symptomatic or asymptomatic. Both groups had bronchodilator reversibility with the albuterol test, using the guidelines of the American Thoracic Society to confirm or rule out the diagnosis of asthma. RESULTS The asymptomatic group had a baseline FEV1 of 1.70 +/- 0.34 l/sec (mean +/- SD) and an endpoint FEV1 of 1.76 +/- 0.42 l/sec; in the symptomatic group the respective values were 1.51 +/- 0.41 l/sec and 1.57 +/- 0.44 l/sec (p < 0.05). A positive reversibility test was found in 13/136 (9.6 %) children in the asymptomatic group and in 22/112 (19.6 %) children in the symptomatic group (p < 0.05). CONCLUSION Because of its low sensitivity, bronchodilator reversibility cannot be considered a diagnostic tool to confirm diagnosis of asthma.