Media
2008-12-10
December, 2008
Asthma reality: over and under diagnosed
Asthma is one of the most common respiratory diseases in Canada, yet many cases remain undiagnosed.
AllerGen Principal Investigator Dr Louis-Philippe Boulet from Laval University was involved in a study recently profiled in the Canadian Medical Association Journal (CMAJ, 18 November 2008, Volume 179, Issue 11) that compared misdiagnosis of asthma in obese versus non-obese patients with a primary care physician’s diagnosis of asthma.
“This study showed that about one-third of both groups did not have asthma after about eight months of follow-up and weaning off medication based on negative methacholine test results,” said Dr Boulet.
The study was developed due to the incidence and prevalence of obesityincreasing concurrently with the incidence and prevalenceof asthma, which indicated a possible link between obesity andasthma. The underlying hypothesis was that some respiratory symptoms associated with obesity could be misinterpreted as asthma.
The prevalence of asthma among Canadians is considered to be as high as 10 per cent of the population.
“Although this study indicates that asthma is often over-diagnosed, the possibility remains that it is also undiagnosed in a significant number of individuals. This issue, therefore, needs to be further explored,” said Boulet.
“We think there are possibly just as many un-diagnosed as there are mis-diagnosed patients.
“This study points out that one of the major care gaps in asthma and pulmonary obstructive diseases globally is the insufficient use of objective measures of airway function to confirm asthma diagnosis - either spirometry, or other methods of assessment of pulmonary function, including bronchoprovocation tests,” said Boulet.
Allergen Principal Investigator Dr Allan Becker, University of Manitoba, Department of Pediatrics said that while asthma is over diagnosed in adults, it remains under-diagnosed in children.
“We need to consider whether it is a wheezing syndrome of asthma or if treatment is appropriate,” said Becker.
“In adults, a normal spirometry test does not rule out asthma, whereas the issue in children is a lack of biologic gold standard tests.
“However, the presence of atopy or a parent/sibling with asthma greatly increases the likelihood that the diagnosis is correct,” said Becker.
AllerGen NCE Inc., one of the federal Networks of Centres of Excellence, is currently conducting numerous studies looking at the diagnosis and treatment of asthma, with the ultimate goal of reducing the social and economic burden posed by the increasing prevalence of asthma, allergy and related disease in Canadian society.
The Allergy, Genes and Environment research network, (AllerGen NCE Inc.), is funded through the federal Networks of Centres of Excellence program. The Networks of Centres of Excellence Canada is a joint initiative of the Natural Sciences and Engineering Research Council, the Canadian Institutes of Health Research, the Social Sciences and Humanities Research Council, and Industry Canada. www.allergen-nce.ca