Medical surveillance programme for diisocyanate exposure.
OBJECTIVE
Surveillance programmes for occupational asthma should reduce the severity of asthma both at the time of diagnosis and after removal from exposure as well as costs related to functional impairment. The aim of this study was to compare the severity and cost of diisocyanate-induced occupational asthma in workers participating in a surveillance programme and in twice the number of workers diagnosed after being referred by their physician.


METHODS
Answers to a self-administered questionnaire led to possible referral for further assessment that included methacholine testing and specific inhalation challenges as the gold standard for confirming occupational asthma. Results Of the 2897 workers who participated, 182 (6.3%) had a positive questionnaire. 79/182 (43%) were referred for further medical assessment and 20 had confirmed occupational asthma by specific inhalation testing. At the time of diagnosis, the 20 screened subjects had a mean PC(20) of 3.35 mg/ml as compared to 1.50 mg/ml (p = 0.05) in the 66 controls. Two years after diagnosis and removal from exposure, the 20 subjects screened had a mean PC(20) of 4.81 mg/ml compared to 1.67 mg/ml (p = 0.03) in controls. Clinical remission occurred in 34% of the screened group compared to 16% of the control group (p = 0.02). The median costs for functional impairment were $C11,900 in screened subjects and $C19,600 in controls (p = 0.04).


CONCLUSIONS
Subjects with occupational asthma screened by a medical surveillance programme have a better outcome both at the time of diagnosis and 2 years after removal from exposure, with lower compensation costs compared to controls.
Department of Chest Medicine, Hôpital du Sacré-Coeur de Montréal, 5400 Gouin Blvd West, Montreal, Quebec, Canada. manon.labrecque@umontreal.ca
Manon
M
Labrecque
Jean-Luc
JL
Malo
Khadija M
KM
Alaoui
Khalil
K
Rabhi
D000328:Adult; D001249:Asthma / Q000139:chemically induced* / Q000175:diagnosis / Q000191:economics / Q000517:prevention & control; D001985:Bronchial Provocation Tests / Q000379:methods; D016085:Bronchoconstrictor Agents; D005260:Female; D006801:Humans; D017953:Isocyanates / Q000633:toxicity*; D008297:Male; D016210:Methacholine Chloride; D008875:Middle Aged; D009784:Occupational Diseases / Q000139:chemically induced* / Q000175:diagnosis / Q000191:economics / Q000517:prevention & control; D016273:Occupational Exposure / Q000517:prevention & control*; D011159:Population Surveillance / Q000379:methods; D011379:Prognosis; D015397:Program Evaluation; D011446:Prospective Studies; D014942:Workers' Compensation / Q000706:statistics & numerical data
D016085:Bronchoconstrictor Agents; D017953:Isocyanates; D016210:Methacholine Chloride