Strategies to Improve Diagnosis and Treatment of Asthma in Canadians

It is not currently known if physicians in Canada are ordering the appropriate diagnostic lung function tests necessary to make correct diagnoses of asthma in Canadians. Our study will enroll 644 randomly-selected Canadians who have been diagnosed with asthma by a physician within the previous five years. We will determine whether lung function tests were originally ordered in these patients to establish their initial diagnosis of asthma. We will also test these patients over a 6-8 week period to determine if they truly have asthma. Those patients in whom the diagnosis appears to have been incorrect will have their asthma medications stopped and we will follow them for one year. The primary outcome of the study will be the proportion of patients in whom the diagnosis of asthma is excluded after one year of follow-up. Should our study determine that diagnostic tests are not being properly employed, or that asthma is commonly misdiagnosed amongst Canadians, then this will provide an impetus for us to develop better strategies to promote more rigorous, objective methods to diagnose asthma in the community.