Validity of the IUATLD (1986) questionnaire in the EGEA study. International Union Against Tuberculosis and Lung Disease. Epidemiological study on the Genetics and Environment of Asthma, bronchial hyperresponsiveness and atopy

Abstract

Setting: No validity study of the IUATLD asthma-like questions has been performed in a group of well-defined, clinically-based asthmatics.

Objectives: To assess the validity of the questions regarding asthmatics included in a case-control study, and to assess their validity as regards bronchial hyperresponsiveness in population-based subjects.

Design: Data from the case-control Epidemiological study on the Genetics and Environment of Asthma, bronchial hyperresponsiveness and atopy (EGEA) were used. The analysis concerned 201 adult asthmatic cases recruited in chest clinics through a standardised protocol and 284 population-based controls.

Results: The analysis of the case-control study regarding asthma showed a sensitivity of 0.56, 0.68 and 0.86 for nocturnal symptoms of cough, shortness of breath, and chest tightness, and a specificity of 0.72, 0.98 and 0.89. As regards bronchial hyperresponsiveness (PD20 < or = 4 mg) in the control group, specificity was high (0.77, 0.99 and 0.90), but sensitivity was markedly lower (0.36, 0.11 and 0.20).

Conclusion: Asthma-like symptoms assessed by the IUATLD questionnaire have good validity, both for specificity and sensitivity, for asthma patients recruited in chest clinics. In general populations, questions have a high specificity, an important criterion in aetiological epidemiological research, and they were designed in that perspective. However their moderate sensitivity limits their usefulness as a screening test.