ECRHS screening questionnaire scoring: a methodological suggestion for asthma assessment. European Community Health Survey.

Univocal definition and classification of Asthma have always been a matter of discussion, and that is reflected in the difficulty of constructing a measure of pathology severity. The European Community Health Survey is a multinational survey designed to compare the prevalence of asthma in subjects, aged 20 to 44 years, in several European areas. In each participating center a sample of 3000 adults filled a self-administered screening questionnaire composed by 9 dichotomous items. Aim of the present study is to investigate unidimensionality of the ECRHS screening questionnaire and to determine and validate a scoring of asthma-like symptoms seriousness. Dimensionality and scoring was determined through a Homogeneity Analysis by Alternating Least Square; while scoring validation was assessed by a cross validation technique. This study found the existence of a sole dimension underlying the screening questionnaire; furthermore a scoring of asthma-like symptoms seriousness was determined with the indication of a cut-off in order to distinguish between asthma symptomatic and non symptomatic subjects.