Physician based surveillance system for occupational respiratory diseases: the experience of PROPULSE, Québec, Canada

To evaluate the feasibility of implementing a physician based surveillance system of occupational respiratory diseases (PROPULSE) in Québec with regard to physician participation rate, characteristics of reported cases, and comparison with official statistics from the Workers' Compensation Board (WCB).

All chest physicians and allergists in Québec were asked to report suspected new cases of occupational respiratory diseases, on a monthly basis, between October 1992 and September 1993. For each case, personal information was collected and the physician's opinion on whether the condition was related to work was categorised as highly likely, likely, and unlikely.

Of the 161 physicians initially approached, 68% participated. Physicians rated 48% of suspected cases as highly likely, 29% as likely, and 20% as unlikely. The most often reported diagnosis was asthma (63%), followed by diseases related to asbestos (16%). Silicosis was less frequent (5%) but it was reported for six workers under 40 of whom five were involved in sandblasting activities. The high proportion of cases of asthma probably reflects the increasing importance of this disease but may also reflect the different patterns of reporting among physicians with different expertise. The distribution of cases by diagnostic category is quite different between the PROPULSE system and that of the WCB (annual mean number of compensated cases during a four year period). Asthma and allergic alveolitis are more frequent in PROPULSE, reactive airways dysfunction syndrome are about the same in both systems, and other diseases are more frequent among compensated cases. The most frequent sensitising agents reported for asthma were the same in both systems (isocyanates, flour, and wood dust). 15% of the PROPULSE cases were not covered by the WCB, and therefore would not be found in the board's official statistics.

A physician based reporting procedure can be implemented as part of a surveillance system to supplement data from other sources and thus provide a better understanding of the occurrence of occupational respiratory diseases.