Validation of the modified International Study of Asthma and Allergies in Childhood questionnaire: Is wheeze alone enough for determination of asthma symptoms prevalence?

Abstract

Background: The International Study of Asthma and Allergies in Childhood (ISAAC) protocol for asthma prevalence depended mainly on self-reported wheezing symptom in the past 12 months. Objective: To evaluate the prevalence of asthma symptoms using self-reported wheezing versus combination of symptoms and spirometric criteria. Materials and Methods: A multi-center cross-sectional study covering Northern, Eastern, Western and Central Sudan was conducted during 2009-2012. A modified ISAAC questionnaire for adults was distributed to university students, academic staff, employee and workers chosen randomly. 3974 respondents were included. Any subject with asthma symptoms was interviewed by another special questionnaire and had a bronchodilator reversibility test. Results: Average overall prevalence of asthma symptoms depending on wheeze only symptom was 10% with regional variation ranged from 6% in El Obeid (Western Sudan) to 13% in Kassala (Eastern Sudan).The use of combination of symptoms (wheeze + shortness of breath or nocturnal cough) was more correlated with the reversibility validated prevalence than wheezing alone in all study sites and total sample. Conclusion: Wheezing alone does not predict the true asthma prevalence and the use of combination of symptoms (wheeze plus) is essential to yield a valid asthma symptoms prevalence.