Objectives: To investigate the use of multiple health data sources for population-based asbestosis surveillance in British Columbia, Canada.
Methods: Provincial health insurance registration records, workers’ compensation records, hospital separation records, and outpatient medical service records were linked using individual-specific study identifiers. The International Classification of Disease (ICD)-9 (501) and ICD-10 (J61) codes were used to identify asbestosis cases. The study population was restricted to adults aged 15 years and older who resided in the province from 1992 to 2004.
Results: A total of 1170 new asbestosis cases were identified from 1992 to 2004 for an overall incidence rate of 2.82 (5.48 for men, 0.23 for women) per 100,000 population; 96% of the cases were male and the average age was 69 years (standard deviation, 10 years). Although the annual number of new cases increased by 30% during the surveillance period (β=2.36, p=0.019), the observed increase in the annual incidence rates was not significant (β=0.02, p=0.398). Workers’ compensation, hospitalization, and outpatient data identified 23%, 48%, and 50% of the total new cases, respectively. Most new cases (82%) were identified through single data sources; 10% of the new cases were only recorded in the workers’ compensation data source, and 36% only in each of the hospitalization and outpatient data sources. Eighty-four percent of the hospitalization cases and 83% of the outpatient cases were not included in the workers’ compensation data source. Three data sources showed different temporal trends in the annual number of new cases and the annual incidence rates.
Conclusions: Single data sources were not sufficient in identifying all new cases and thus led to serious underestimation of the true burden of asbestosis. Integrating multiple health data sources will provide a more complete picture in population-based surveillance of asbestosis and other occupational diseases.