Cases of asthma in Canada may be overdiagnosed by 30 per cent: study

From the Canadian Press:
Almost a third of adult Canadians diagnosed with asthma and taking medications to treat their wheezing, coughing and shortness of breath may not actually have the allergic respiratory condition at all, researchers say.

In a study of about 500 adults who had previously been told they have asthma, airway-function and other tests showed that about 30 per cent did not in fact have the disease, suggesting that asthma may be significantly overdiagnosed in Canada.

"What we think is happening ... is that if patients come to a physician complaining of shortness of breath or cough or wheeze, oftentimes the physician will assume that the diagnosis is asthma, and based on the patient's history and complaints prescribe medicines to treat asthma," lead investigator Dr. Shawn Aaron said from Ottawa.

"And what they won't do is order the appropriate diagnostic test to confirm asthma."

Aaron, head of respiratory medicine at Ottawa Hospital and the University of Ottawa, said a doctor's suspicion that a patient has asthma should be followed up by confirmatory tests, including spirometry. ...more