Life Cycle Sessions: Diagnosis... Revisited
This is Part 1 in the Life Cycle Sessions series, providing an overview of research presented at Asthma Canada’s Breathe Easy: The Life Cycle of Asthma conference in Toronto, Ontario, on October 21, 2017. However, these posts don’t have to be read in order! Learn more here.
It’s true that once you have asthma, you have asthma for life, although sometimes changes in your environment or other factors in your body can cause your asthma to go into “remission”, where you no longer have symptoms of asthma, and remain asymptomatic without treatment 1. However, what if your diagnosis was incorrect? What if you’ve spent years, possibly decades, treating asthma and it turns out… asthma wasn’t the problem all along? This situation is more common than you might think. Dr. Shawn Aaron, one of the primary investigators on many Canadian studies about misdiagnosis of asthma, not only presented on this topic at Asthma Canada’s Life Cycle of Asthma conference on October 21, 2017, he also received an Asthma Canada Leadership Award for Health Research for his contributions to health research.
What’s the problem? Over-diagnosis? Under-diagnosis?
Technically, both. A 2007 literature review states that more than 60% of people with asthma do not see a doctor about symptoms—meaning they may be undiagnosed—yet when asking students with asthma in Great Britain, 39% of students with asthma denied having the disease. 2 These factors can both skew the statistics of how asthma prevalence is measured, both towards under-diagnosis and under-reporting of diagnosis. The over-diagnosis/under-diagnosis conundrum seems to flip flop by population studied (even a cursory Google search will show the dissonance!).
Contributing factors to (mis)diagosis
Dr. Aaron began by defining asthma per the Global Initiative for Asthma (GINA) diagnostic guidelines, as overdiagnosis is the direct result of not confirming that asthma is truly the problem 1 GINA guidelines for making a diagnosis of asthma combine clinical history (symptoms), observations, and pulmonary function tests—basic spirometry. 3 However, many patients never get to this final step. In the Canadian Asthma Diagnosis Study presented on by Dr. Aaron, of a population of 701 people with asthma recruited by random phone dialling, only 51% had underwent spirometry to confirm their asthma diagnosis. 4 Dr. Aaron lamented that high cholesterol or diabetes would never be diagnosed without a blood test, so why should asthma be diagnosed without breathing tests? 1
By the end of the Canadian Asthma Diagnosis Study, in which patients underwent extensive testing, 33% of patients were determined to not have asthma, and were successfully titrated off of asthma medicines, with close monitoring of symptoms, peak flow variability testing, and clinical monitoring by methacholine challenge 3 weeks following medication reduction or discontinuation. 1 Three weeks following discontinuation of medication, they were re-evaluated for asthma or differential diagnosis. 1 21% of patients in the study did not have clinical evidence of asthma, but the respirologists conservatively retained their diagnosis based on subjective findings.
Yet, asthma misdiagnosis remains a problem. Some individuals had achieved symptom remission and could no longer be classified by GINA guidelines as having asthma, although likely had asthma in the past—one classic example being a person with a cat allergy who no longer lived with a cat and thus, no longer had any asthma symptoms 1, others had differential (alternative) diagnoses such as subglottic stenosis—narrowing of the trachea just beneath the vocal cords, often caused by scar tissue, and typically treated with surgery. 1, 5
“Patients are smarter than their doctors"
In cases where the asthma diagnosis was not warranted, Dr. Aaron has noticed that these are often the patients who might be deemed “non-compliant”, or go off of their meds by themselves. “Patients are smarter than their doctors,” he said—when asthma medication isn’t helping, patients often throw in the towel. 1
To conclude, Dr. Aaron offered practical applications for patients of the research:
- Insist your doctor orders spirometry to try and confirm asthma, prior to assigning a diagnosis. There are less than 2% of patients that cannot perform spirometry to provide more data—so its 98% likely that you can do the test. 1
- If you are asymptomatic (potentially “in remission”) while on treatment, ask your doctor to order spirometry. If spirometry is normal, you may be able to taper asthma meds—and in some cases, discontinue them under proper supervision. 1
As someone who had difficult to control asthma for the first several years after my asthma diagnosis, I personally questioned my diagnosis. Since then, I’ve had many rounds of spirometry as well as reversibility testing and self-advocated to have a methacholine challenge test done to confirm my asthma diagnosis—it was positive, and thus, I have asthma. In addition, I’ve had allergy tests done, and have been screened for vocal cord dysfunction by an ENT. But, it took years to get all those tests done—and had I known what I know now, I’d have tried to have them done sooner, to ensure we were dealing with the right thing! Fortunately we were, but it was still a long road.
For a complete picture of Dr. Aaron’s presentation, check out the video recording here.
How were you diagnosed with asthma? Has your asthma diagnosis since been confirmed with testing or “revisited” in any way? Let us know in the comments!
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