Validation of the IUATLD Bronchial Symptoms Questionnaire in Butajira, Ethiopia
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Date
2007-01
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Addis Ababa University
Abstract
Background: A number of epidemiological research conducted on asthma obtained increase in prevalence of wheeze over time and generally varying results. However most epidemiological studies on asthma have used symptom questionnaires as their primary markers of disease, it is therefore not clear whether the observed differences in symptom prevalence reflect true differences in underlying disease, or is due to reporting, labeling or ascertainment bias. The main objective of this study was to determine the validity and repeatability of the IUATLD questionnaire measure of self-reported wheeze in Butajira, southern Ethiopia.
Method: To validate the questionnaire 200 individuals with wheeze and 200 with non wheeze aged 8-40 years were randomly selected from a study done in 2003 in Butajira. IUATLD questionnaire was administered twice to obtain data on wheeze and asthma and then these subjects undergone either a standardized exercise challenge test or took bronchodilator. For the analysis of the asthma question, a subset of wheezers with self-reported asthma and a control group of non-wheezers plus a random sample of the wheezing non-asthmatics proportionate to that in the original random sample was used.
Result: The question wheeze in the last twelve months respectively achieved a Kappa value of 61.3% over the four weeks period and 19.1% over the three years period. Its PPV in the two cases of analysis were 7.34% and 8.6% while the NPV were 97.0% and 96.6%. The four-week and three year Kappa value for the question, "Have you ever had asthma?" were respectively 74.9% and 46.2%. Its PPV in the two cases of analysis were 12.1% and 25.0% while NPV were 97.2% and 97.1%.
Conclusion: To conclude, the IUATLD wheeze and asthma questions appeared more repeatable in the short term, but don’t seem to identify the same disease entity as that identified by an exercise challenge test. Before this questionnaire is used further in epidemiological studies in Ethiopia, it is important to validate it against other reference tests, including physician diagnosis and possibly one of the non-invasive measures of airway of inflammation such as fractional expired nitric oxide (FENO
Key words: Validity, repeatability, exercise challenge test and asthma questionnaire
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Keywords
Validity, Repeatability, Exercise challenge test and asthma questionnaire