Asthma is overdiagnosed in an estimated 30 percent of Canadians, according to new findings. Lead study author Shawn Aaron said, “Careful testing revealed that 33 percent of people who had been recently diagnosed with asthma in the community did not have current asthma even after withdrawal of asthma medications.”

The study randomly recruited 701 non-smoking participants from 10 Canadian communities with a history of reported asthma. The researchers obtained the information on how the participants were diagnosed. Spirometry, home peak flow, and symptom monitoring, as well as repeated bronchial challenge tests were used to assess participants. Participants were tapered off asthma medications over the course of four years.

Of the group, 613 were conclusively diagnosed with asthma. Those with unconfirmed asthma diagnosis had no evidence of airflow blockage or bronchial hyper-reactivity or acute asthma worsening despite tapering off all asthma medications. Those without a diagnosis were sent to pulmonologists and followed for one year.

The authors wrote, “Pulmonologists diagnosed alternative diagnoses instead of asthma in 87 percent of these subjects. Results to date indicate that 81 percent in whom asthma was excluded did not restart asthma medications nor require healthcare utilization for asthma during the subsequent 12-month follow up period.”



How is asthma diagnosed?

The first step to properly diagnosing asthma is to get a detailed medical history along with a physical examination. There are numerous tests your doctor could perform, including a lung function test, and a chest or sinus X-ray. While your doctor is collecting your medical history, they may ask questions regarding your symptoms along with your family history. Your doctor will also want to know about any previous allergies or eczema, as these conditions can increase your risk of asthma. Also, tell your doctor if you are exposed to any environmental factors that could trigger asthma, such as pollution, smoke, etc.

The physical exam will look at your ears, nose, throat, skin, chest, and lungs. This is when a lung function test or X-ray will be performed.

There are three different types of lung function tests: Spirometry, peak airflow, and trigger tests. The spirometry test is when you breathe into a device that measures the amount of air you are able to breathe and records the rate of flow. Peak airflow is a small, handheld device that measures the rate at which the air is expelled from the lungs. You will need to breathe into the device as fast and hard as possible. Lastly, trigger tests allows the patient to uncover what triggers their asthma. Your doctor exposes you to common triggers to cause a reaction. If you don’t have asthma you will not react.

Getting properly diagnosed for asthma can help you start a condition management plan in order to relieve your symptoms.