Study objective: To evaluate the effect of treatment with beclomethasone dipropionate (500 microg bid) and salmeterol (50 microg bid) on lung function and respiratory symptoms in 20 subjects with occupational asthma (OA) still exposed to the work environment cause of their disease.
Methods: At enrollment and every 6 months for 3 years, respiratory symptom score (from 0 [no symptoms] to 2 [moderate-to-severe symptoms]), spirometry, methacholine challenge, peak expiratory flow (PEF) variability, and the use of rescue salbutamol were evaluated. During the 3 years of follow-up, 10 subjects were excluded from the study because they retired or changed jobs.
Measurements and results: Symptoms of work-related asthma started 12.6 +/- 13.1 years (mean +/- SD) before diagnosis. At baseline, mean FEV(1) was 80.2% of predicted values and provocative dose of methacholine causing a 20% fall in FEV(1) (PD(20)) was 1,001 +/- 1,275 microg; the workers received 2.1 +/- 2.4 puffs of salbutamol per day. After 3 years, no significant differences in any of the morbidity outcomes (FEV(1), PD(20), PEF variability, use of rescue salbutamol, respiratory symptom score) were found as compared with baseline or run-in values.
Conclusions: Regular treatment with inhaled corticosteroids and long-acting bronchodilators seems to prevent respiratory deterioration over a 3-year period in workers with mild-to-moderate persistent OA who were still exposed at work to the environmental cause of their disease.