Validation of a school-based written questionnaire for asthma case identification in Argentina

Recognition of asthma in community-based surveys can be problematic. We sought to develop and validate questionnaires that could identify elementary school-aged children likely to have asthma or who had poorly-controlled asthma. Questionnaires for parents (PQ) and students (SQ) to complete were developed using guidance on question wording from a focus group consisting of children with asthma and their parents. The gold standard for this study was a pulmonologist determination of asthma and this was used to calculate sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for each question and for combinations of questions. Questionnaires were distributed to 830 children attending elementary schools in Trelew, Argentina and 96% were returned. Test-retest reliability was determined in 221 randomly selected parents and children and very good levels of agreement were seen for individual questions. Asthma was diagnosed in 92 students. Overall, the PQ was able to detect asthma better than the SQ. Optimal diagnostic ability came by combining questions from the PQ and SQ. Not surprisingly, these questionnaires had a better NPV than PPV and can be used to determine which children require further evaluation.