Studies Reveal Increasing Misdiagnosis of Asthma

Asthma is a chronic disease that causes inflammation and narrowing of the airways, leading to recurrent symptom flare-ups such as wheezing and coughing. Patients who have been diagnosed with asthma face the prospect of taking medication to manage the disease for their lifetime.

However, recent studies have revealed that asthma misdiagnosis is much more common than previously thought. Some patients have only discovered that they were, in fact, asthma-free after having taken the medications for more than a decade.

Asthma misdiagnosis may be as high as 30 percent

A study published in the Canadian Medical Association Journal in November 2013 evaluated about 500 adults from various cities in Canada. Approximately half of the study participants were obese, while the other half were non-obese. The researchers conducted initial lung function tests, and then instructed the study participants to discontinue their asthma medication. The subsequent testing revealed that approximately 30 percent of the total study group did not actually have asthma. The misdiagnosis of asthma affected 29 percent of study participants who were non-obese and 32 percent of participants who were obese.

The participants who were found to not have asthma gradually discontinued their asthma medications permanently. In a follow-up evaluation six months later, the researchers found that only eight percent of that group had symptoms that were still bothersome enough to warrant a visit to their healthcare professionals. The lead study author noted that those cases likely represented persistent viral infections or other issues that can cause symptoms similar to asthma. The study author also emphasized the importance of discontinuing asthma medication only under the supervision of a qualified healthcare professional.

Importance of differential diagnosis

The process of testing a patient to rule out other possible causes of symptoms is called differential diagnosis. For example, even when a patient presents with symptoms of asthma, a physician may perform tests in addition to lung function tests to determine whether another condition could be causing the symptoms. When a patient presents with possible asthma, the physician can perform a physical examination, review the patient’s medical history, and order x-rays to check for physical airway obstructions.

Lab tests can rule out a variety of diseases, while a sweat test may rule out cystic fibrosis. Other helpful tests for differential diagnosis include:

• Barium swallow under fluoroscopy
• Electrocardiogram
• CT scan
• Bronchoprovocation
• Allergy testing
• pH probe testing

If a patient has been undergoing treatment for asthma, yet the symptoms are not controlled, the patient’s physician may recommend undergoing these additional tests to consider other possible causes. Sometimes, a patient who is misdiagnosed will actually have one of the following conditions:

• Viral infection
• Sinus infection
• Airway obstruction
• Vocal cord dysfunction
• Heart failure
• Cystic fibrosis
• Enlarged lymph nodes
• Cancer
• Bronchopulmonary dysplasia
• Pulmonary embolism
• Acid reflux

Dangers of medical misdiagnosis

Among those who are misdiagnosed, discontinuing medication offers significant benefits – both financial and medical. In the U.S., costs related to asthma totals $50 billion every year in doctor visits, medications, and similar expenses. If the results of the study can accurately be extended to the rest of the population diagnosed with asthma, then ceasing treatment for a non-existing condition would theoretically save $16.6 billion each year.

Furthermore, a misdiagnosis of asthma could have serious health implications. When a patient is misdiagnosed and is undergoing treatment for an illness he doesn’t have, he is at risk of side effects and complications from those medications. Systemic steroid medications can cause side effects such as weakness, weight gain, upset stomach, and acne. More serious side effects may include bone loss, vision changes, mood changes, behavioral changes, and slowing of growth in children. The longer these drugs are used, the greater the risk of side effects.

Additionally, patients who are misdiagnosed aren’t being treated for the true cause of their symptoms. In some cases, the cause may be relatively minor, such as a viral infection or sinus infection. In other cases, the patient may have an undiagnosed, life-threatening condition, such as pulmonary embolism or heart failure.