Occupational asthma: a longitudinal study on the clinical and socioeconomic outcome after diagnosis

To evaluate the clinical outcome and socioeconomic consequences of occupational asthma (OA).

Twenty-five patients with OA both to high- and low-molecular-weight agents (3 and 22, respectively) confirmed by specific inhalation challenge were followed up for 12 months after the diagnosis. Upon diagnosis, each patient received a diary on which to report peak expiratory flow rate (PEFR), symptoms, drug consumption, expenses directly or indirectly related to the disease, as well as information regarding personal socioeconomic status. At each follow-up visit (1, 3, 6, and 12 months), the patients underwent clinical examination, spirometry, methacholine (Mch) challenge, and assessment of diary-derived parameters and socioeconomic status. Asthma severity (AS) was classified into four levels, based on symptoms, drug consumption, and PEFR variability.

At 12 months, 13 patients (group A) had ceased exposure; the remaining 12 patients (group B) continued to be exposed. At diagnosis, FEV1 percent and provocative dose causing a 20% fall in FEV1 (PD20) of Mch were lower in group A than in group B; patients of group A were also characterized by significantly higher basal AS levels. At 12 months, no significant variation in FEV1 percent or PD20 was found for either group, while AS levels improved in both groups, the change being more marked for group A than group B. Pharmaceutical expense at 12 months significantly (p < 0.05) decreased, as compared with the first month, in group A, whereas it tended to increase in group B. In group A, 9 of 13 subjects had reported a deterioration of their socioeconomic status as compared with 2 of 12 in group B (p < 0.01). A significant loss of income was registered in patients of group A (median 21.45, 25th to 75th percentiles 16.9 to 25.8 Italian liras x 10(6) on the year preceding diagnosis and 15.498, 10.65 to 21.087 Italian liras x 10(6) on the year after diagnosis; p < 0.01), whereas no significant change was seen for patients in group B.

In OA, cessation of exposure to the offending agent results in a decrease in asthma severity and in pharmaceutical expenses, but it is associated with a deterioration of the individual's socioeconomic status (professional downgrading and loss of work-derived income). There appears to be a great need for legislation that facilitates the relocation of these patients.