Asthma in Iranian Schoolchildren: Comparison of ISAAC Video and Written Questionnaires

Background: The international study of asthma and allergies in childhood (ISAAC) is used to define the prevalence and severity of asthma in different regions, In this study we followed the performance of the ISAAC video and written questionnaires (YQ and WQ) to classify asthma in 13-14 yr-old schoolchildren, Methods: The present study was carried out on 3540 schoolchildren 13 to 14-yrs-old using the YQ and WQ. The students were also asked to answer a separate question if they had ever been clinically diagnosed as asthmatic. The Kappa index was used to find degree of agreement between YQ and WQ regarding asthma symptoms. The sensitivity, specificity and Youdeu s index of both questionnaires were also determined. Results: The most frequent asthma symptom was wheeze after exercise in both YQ (15%) and WQ (23%). Correlations between positive responses to the corresponding questions in the YQ and WQ were significant (P(LESS THAN)O.OO I). The sensitivity of both questionnaires to the question of asthma diagnosis by physician ranged between 0.16 and 0.68. Except for wheeze limiting speech and current wheeze, the WQ had higher value of Youdens index (0.25 - 0.46). The specificity of questions in YQ for asthma diagnosis by physician was ranged between 0.84 and 0.99. Conclusion: Both WQ and YQ had low sensitivity, but WQ showed higher value of Youdens index and the YQ exhibited good specificity. Therefore, one may consider the WQ for prevalence and YQ for relative risk studies.