Misdiagnosing Lung Disease Is Far Too Common, Poses Many Risks. How Can Clinicians Improve?

Andrew Shorr, MD, MPH


April 17, 2017

This is Andy Shorr from MedStar Washington Hospital Center, with the Pulmonary and Critical Care Literature Update. I would like to discuss an article that was recently published in JAMA by Aaron and colleagues,[1] dealing with asthma diagnosis.

Many of us in pulmonary medicine see patients with asthma in our clinical practice and then we question the entire diagnosis of asthma. We come to find that the patient either never had appropriate diagnostic testing—in fact, had some alternate diagnosis—or has been placed on a set of inhalers that have never been adjusted or tapered. [Aaron and colleagues] really tried to get at the scope of that problem.

They began by looking for a sample of patients through a random digit–dialing process in Canada to identify a representative sample of approximately 700 people who had a diagnosis of asthma, who were clinically stable, and who had not been on oral glucocorticoids but were also able to do spirometry.

Eventually, 613 patients completed the study, in which they underwent an aggressive series of confirmatory tests to assess whether they truly had asthma. Patients went through an evaluation with the pulmonologist; they underwent a bronchoprovocation test or initially an albuterol challenge with spirometry, followed by bronchoprovocation testing if that was negative. All throughout, they were having their asthma medicines reduced if they remained stable.

Among the 613 patients whom they evaluated, 2%, first of all, were found to have diagnoses that were potentially life-threatening and certainly were not asthma. This included pulmonary arterial hypertension, idiopathic pulmonary fibrosis, and other forms of interstitial lung disease. Second, they found that a third of patients did not have anything that resembled asthma. About a third clearly did not have a syndrome resembling asthma, not only based on their spirometric evaluation, not only based on methacholine challenge, but also based on the fact that their medicines were all discontinued over a protocolized period of time and they remained stable for 12 months. [Editor's note: Patients continued to exhibit no clinical or laboratory evidence of asthma.] Among the patients who did have a diagnosis of asthma, many were able to have their asthma medications reduced, and again, many did well.

These authors also found that about half of the patients who were diagnosed with asthma and did not have asthma, never had spirometric testing. This is truly troublesome in terms of the state of care that we provide to our patients with asthma when they are seeing primary care providers. It really emphasizes several points. First of all, spirometric and objective testing is crucial for the diagnosis of asthma. You may miss other diagnoses if you are not doing this. Second, if the patient does not have asthma and you are giving them medications that may be costly and have side effects, you are doing no good.

The most common diagnosis identified in the patients who did not have asthma was just allergic rhinitis. A group of bronchodilators is not going to improve that.

The authors also showed that there are clearly people who did have asthma, based on having had spirometry by their primary care provider, in whom it improved and evaporated. It really demonstrated that asthma is a relapsing, remitting, and potentially resolving syndrome. Maybe these patients had post-airway hyperreactivity after a viral syndrome, maybe they had asthma when they were in a certain workplace environment and exposed to an allergen—who knows. It demonstrates once again that we really need to harken to the guidelines about re-evaluating, stepping down therapy, and reassessing. We cannot just do fire-and-forget, because first of all, we may be firing at the wrong target; we may not even have the right diagnosis. And second, we need to be able to step down because our patients do not need to be on the same degree of inhaled corticosteroids and/or LABA (long-acting beta2 agonists) for the rest of their lives just because they carry a diagnosis of asthma.

I think this is important medical information. It illustrates this problem in the community, and it really emphasizes our role as pulmonologists to educate our primary care providers about these problems, and also about the need to get spirometry rather than just calling anything that wheezes "potentially asthma."

This is Andy Shorr from Washington, DC.


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