Assessment of work-related asthma prevalence, control and severity: protocol of a field study

Background: There are still uncertainties regarding the respective prevalence, diagnosis and management of occupational asthma (OA) and work-exacerbated asthma (WEA). Indeed, there is as yet no standardized methodology to differentiate the diagnoses of OA and WEA. A proper management of both OA and WEA requires tools for a good phenotyping in terms of control, severity and quality of life in order to propose case-specific therapeutical and preventive measures. Moreover, there is a lack of knowledge concerning their actual costs to the patient and to society.
Methods: This project aims at comparing 3 groups of asthmatic subjects at work: subjects with OA, subjects with WEA, and subjects with non-work-related asthma (NWRA) in terms of control, severity and quality of life on the one hand, and estimating the prevalence of OA, WEA and NWRA in active workers on the other hand. A first step will be to devise and apply a standardized diagnosis procedure of WEA and OA. This study includes an epidemiological part in occupational health services by volunteering occupational physicians, and a clinical case-study based on potentially asthmatic subjects referred to ten participating University Hospital Occupational Diseases Departments (UHODD) because of a suspected WRA. The subjects’ characterization with respect to OA and WEA is organized in three steps, the more advanced, the more specific. In Step 1 (epidemiological part only), occupational physicians screen for potentially actively asthmatics through a self-administered questionnaire given to workers seen in mandatory medical visit. In step 2 (both parts), the subjects with a suspicion of work-related respiratory symptoms answer a detailed self-administered questionnaire and perform a two-week OASYS protocol enabling us, using a specifically developed algorithm, to classify them into probably NWRA, suspected OA, suspected WEA. The two latter groups are referred to UHODD for a final harmonized diagnosis (step 3). Finally, direct, indirect and perceived costs related to OA and WEA will be explored among a group of WRA cases diagnosed in step 3 during a one year follow-up.