Asthma has emerged as an important respiratory and public health problem in Canada. Population-based studies of asthma are hampered by the lack of a clear definition of the disease and its variable course. Standard methods for population studies of asthma include surveying population samples using questionnaires and examining people in laboratories. These procedures are extremely expensive (in terms of both finances and manpower), time consuming and limited to relatively small samples. It would be helpful if, at least for some purposes, these procedures could be replaced by cheaper techniques with adequate validity. Administrative databases such as the Manitoba Population Health Repository offer such an option. While the validity of the Manitoba data has been studied and found acceptable both generally and in a number of specific areas , this has not yet been done for asthma. Suitable asthma surveys to compare with administrative data have been lacking.
As part of a Canadian multicentre study to estimate the prevalence of asthma in 1993 to 1994, a sample of the general population in Winnipeg, Manitoba was surveyed. The objective of this analysis is to determine the agreement between prevalence estimates obtained from the population survey and the prevalence of asthma in the same individuals as obtained from the Manitoba Health database.