Validation of the ISAAC Standardized Questionnaire Used by Schoolchildren from Mexicali, Baja California, Mexico

Abstract

Background . In Mexico, several studies have been conducted under the ISAAC methodology; nevertheless, no validation studies of the ISAAC questionnaire based on objective clinical testing in our country have been published. Aims of the Study . To validate the ISAAC questionnaire, used in a study of prevalence of allergic diseases, based on medical, respiratory, and allergic evaluations of schoolchildren being 11 to 16 years old in Mexicali, Mexico. Material and Methods . We conducted a cross-sectional study to validate the ISAAC questionnaire through the generation of an index (considered as gold standard) using pre- and postbronchodilator spirometry test, exhaled nitric oxide measurements, and atopic evaluations. 114 schoolchildren were included (23 asthmatics with respiratory symptoms and 91 nonasthmatics without respiratory symptoms) and we evaluated the sensitivity, specificity, and positive and negative predictive value of the questionnaire using discriminant analysis. Results . We observed sensitivity of 35.2% and specificity of 93.3% and the positive and negative predictive values were 82.6% and 61.5%, respectively. Conclusions . Our findings indicate that the ISAAC Mexican version questionnaire was less sensitive and more specific when compared to the gold standard; however, it is adequate and able to discriminate children with and without asthma and a useful tool to use in epidemiological studies.