Asthma Not Found in One Third of Adults with Previous Diagnosis

A new Canadian study has found that a significant number of adults who were previously diagnosed with asthma do not have the disease upon reassessment. These surprising findings were published this week in the January 17 issue of JAMA.

The study’s authors explained that, "Among adults with physician-diagnosed asthma, a current diagnosis of asthma could not be established in 33.1% who were not using daily asthma medications or had medications weaned. In patients such as these, reassessing the asthma diagnosis may be warranted."

In a recent interview with ResearchGate, the study’s lead author Shawn Aaron, MD, explained the possible reasons why he and his colleagues were unable to find asthma in so many patients that had been previously diagnosed.

“There are two reasons for this,” says Aaron. “Firstly, some patients were misdiagnosed in the community – meaning they never had asthma to begin with. Secondly, some had asthma, but it was inactive – meaning it was in remission.”

The study involved 701 adults who had received an asthma diagnosis by their physician within the last 5 years. Researchers reviewed information documented by the treating physician to determine how the diagnosis was made. Then, the study’s pulmonologist confirmed or ruled out the diagnosis using serial monitoring of symptoms, home peak flow, spirometry (a measure of lung function), and confirmatory bronchial challenge tests.

Those adults who tested negative for asthma were weaned off their medications using a predefined protocol and monitored for one year. Alternative diagnoses were assigned when necessary.

Of the 613 patients who completed the study, 203 were determined to not have asthma as previously diagnosed. Only 2% of the study’s participants had serious cardiorespiratory conditions that had been misdiagnosed as asthma.

Aaron says, “A lot of other diseases can present with cough, shortness of breath, and wheeze. For instance, serious diseases like congestive heart failure or pulmonary embolism can present with these symptoms, as well as much less serious diseases like allergic rhinitis or heartburn. Asthma is not that difficult to diagnose, but doctors must order the proper tests to make the diagnosis correctly. If they don’t order the tests, they are more likely to get the diagnosis wrong, we found.”

To learn more, read the abstract.