Distinct Clinical Phenotypes of Occupational Asthma due to Diisocyanates

Objective: To assess whether diisocyanate occupational asthma represents a unique phenotype. Methods: We studied 187 patients with diagnosis of asthma due to diisocyanates confirmed by a positive specific inhalation challenge. The simplified algorithm from severe asthma research program (SARP) (Moore et al, 2010) was applied to classify patients into five clusters. Results: Our patients were allocated in three of the five clusters described in common asthma, since the most severe Clusters (4 and 5) were not represented. Cluster 2 was the most populated, as in common asthma, and included the youngest patients with the shortest duration of exposure to the sensitizers. Cluster 3 included older men patients with worse lung function and longer occupational exposure. Conclusions: Diisocyanate asthma is a heterogeneous disease. Differences across clusters include demographic characteristics, lung function, and chronology of diisocyanate exposure.