Occupational asthma induced by isocyanates is relatively common and is associated with adverse socioeconomic consequences. Work exposure cessation is the most recommendable strategy after diagnosis, but often is not sufficient for the patient's recovery.
Our aim was to assess the long-term impact of diagnosis of asthma on employment status in patients exposed to isocyanates and with work-related respiratory symptoms.
We compared 32 subjects with isocyanate induced occupational asthma (OA+) confirmed by positive specific inhalation challenge (SIC), 14 subjects with work-exacerbated asthma (WEA, active asthma but negative SIC) and 18 non-asthmatic subjects (NA, respiratory symptoms, but no objective signs of asthma and negative SIC).Job history, asthmatic symptoms by Asthma Control Test (ACT), lung function by spirometry and use of anti-asthma drugs were evaluated in each subject at diagnosis and after 10-year follow-up.
Clinical and functional features were comparable in the three groups at diagnosis. At follow-up, there were no differences among groups in the percentage of subjects who had changed job (OA+ 56%, WEA 58%, NA 61%). A minority of OA+ remained exposed to isocyanates (9%), while this occurred more frequently in WEA (29%) and NA (22%). The rate of subjects who recovered was 66.7%, 43.5% and 22% for NA, OA+ and WEA, respectively. In all groups, the greatest proportion of recovery was observed in subjects removed from exposure.
In conclusion, work-related respiratory symptoms were associated with a moderate work disability regardless of diagnosis of OA. The avoidance of exposure to isocyanates was associated with better prognosis irrespective of the initial diagnosis.