Asthma misdiagnosis rife?

asthma reliever puffer on its side

A new study by Canadian scientists suggests that a third people who have been diagnosed with asthma could put their puffers away for good

The researchers suggest in a study appearing in the January 17 issue of JAMA that there is a high chance that patients’ original GPs might have misdiagnosed asthma, or that the condition went away by itself.

Because an asthma diagnosis is commonly given after a single consult, the authors suggest that physicians should not be afraid to order extra tests to be performed to confirm the original diagnosis.

An attached editorial says that considering a questionnaire found around 20% of people who were diagnosed with asthma onset under the age of 20 no longer had the condition, there is need for extra physiological tests to prove they actually had asthma in the first place.

The study showed that among adults with a previous physician diagnosis of asthma, a current diagnosis could not be established in about a third who were not using daily asthma medications or had medications weaned.

The researchers speculate that the failure to confirm the diagnosis could be because of spontaneous remission or misdiagnosis.

Diagnosis of asthma in the community can be difficult and although asthma is a chronic disease, the expected rate of spontaneous remissions of adult asthma and the stability of diagnosis are unknown, the authors say.

Shawn D. Aaron, M.D., of the Ottawa Hospital Research Institute, University of Ottawa, Canada, and colleagues conducted a study that included 701 adults who reported a history of physician-diagnosed asthma established within the past five years.

All participants were assessed with home peak flow and symptom monitoring, spirometry (measures lung function), and bronchial challenge tests, and those participants using daily asthma medications had their medications gradually tapered off over four study visits. Participants in whom a diagnosis of current asthma was ultimately ruled out were followed up clinically with repeated bronchial challenge tests over one year.

Of 701 participants, 613 completed the study and could be conclusively evaluated for a diagnosis of current asthma, which was ruled out in 203 of 613 study participants (33%). Twelve participants (2%) were found to have serious cardiorespiratory conditions that had been previously misdiagnosed as asthma in the community.

After an additional 12 months of follow-up, 181 participants (30%) continued to exhibit no clinical or laboratory evidence of asthma.

Participants in whom current asthma was ruled out, compared with those in whom it was confirmed, were less likely to have undergone testing for airflow limitation in the community at the time of initial diagnosis (44% vs 56%, respectively).

More than 90% of participants in whom asthma was ruled out had asthma medications safely stopped for an additional one-year period.

“Two phenomena may account for failure to ultimately confirm current asthma in 33.1% of the study cohort: one, spontaneous remission of previously active asthma; and two, misdiagnosis of asthma in the community,” the authors write.

“At least 24 of 203 participants (11.8%) in whom current asthma was ruled out had undergone pulmonary function tests in the community that had been previously diagnostic of asthma.

“These participants presumably experienced spontaneous remission of their asthma at some time between their initial community diagnosis and entry into the study.

“This study also suggests that misdiagnosis of asthma may occasionally occur in the community.

“In 2% of study participants, a serious untreated cardiorespiratory condition was identified that may have been previously misdiagnosed as asthma.

“In addition, the study demonstrated that failure to consistently use objective testing at the time of initial diagnosis of asthma was associated with failure to confirm current asthma.

“These results suggest that whenever possible, physicians should order objective tests, such as prebronchodilator and postbronchodilator spirometry, serial peak flow measurements, or bronchial challenge tests, to confirm asthma at the time of initial diagnosis.”

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  1. Jarrod McMaugh

    Chronic respiratory illnesses are quite difficult to diagnose accurately without performing diagnostic investigations. If a clinician is not working in this area on a daily basis, it can be very challenging to correctly diagnose the presenting without adequate diagnostic protocols in place.

    There is quite a lot of confusion among clinicians who see respiratory illness less often; COPD and asthma are often conflated, which is made worse when gold-standard diagnostic processes aren’t used. The number of times I see a patient with COPD and no history of asthma being prescribed ongoing inhaled cortisones despite the evidence is mind-boggling.

    • Toorisugarino Isha

      What is the gold standard for asthma diagnosis? If you read the guidelines (eg. Australian Asthma Handbook) you will find that such a convenient tool does not exist. Asthma is a heterogenous disease, and one where the diagnosis is made clinically. Lung function, bronchoprovocation tests and serum biomarkers help to support the diagnosis and provide phenotypic differentiation. Oftentimes it is quite justified to treat empirically and monitor for response. In contrast, the diagnosis of COPD should never be made without spirometry, as by definition there must be fixed airflow obstruction.

      There is increasing recognition that COPD and asthma can co-exist. Treatment for both is quite appropriate for patients with symptoms of the asthma-COPD overlap syndrome.

      With regards to inhaled corticosteroids in COPD, I agree that they may have a detrimental effect when used as monotherapy. However, used in combination with inhaled LABAs they are integral in the management of severe COPD – decreasing mortality, symptoms and frequency of exacerbations. Both local and international guidelines advocate their use in this population.

      • Jarrod McMaugh

        G’Day Toorisugarino

        With regards to this point – “Oftentimes it is quite justified to treat empirically and monitor for response” I agree with everything except the word oftentimes.

        There are certainly exceptions that make empirical treatment without any investigation the best course of action (ie the extremely frail, young children, etc), but it should be an exception, not the norm.

        I agree that there is increasing recognition of COPD and asthma co-existing – this will only increase with time as asthma diagnosis as a proportion of population increases.

        Despite this, there is still a proportion of patients who are being treated as if they have asthma, when in fact they have COPD. In patients who have COPD, the evidence clearly shows that the benefits of **regular** ICS are outweighed by the increased risks of pneumonia; conversely patients with asthma have a greater benefit from using an ICS every day at the lowest tolerated dose, even when symptoms are controlled.

        Use of ICS in COPD as a regular (daily) medication (regardless of LAMA use), rather than reserving for flare-ups, doesn’t improve morbidity, and increases mortality. Patients with uncomplicated COPD (ie no asthma) would be far better served with combination LAMA/LABA than regular ICS.

        • Toorisugarino Isha

          I agree that thorough investigations should be performed wherever possible. I do not mean to suggest that no investigations be requested at all, but rather my point is to ask: to what extent do you investigate? If a non-smoking high school student presents to you with active symptoms consistent with asthma, a history of atopy and normal spirometry would you subject them to a bronchoprovocation test or suggest a trial of asthma therapy and monitor the response?

          There certainly is strong evidence suggesting increased risk of severe pneumonia with inhaled steroids but it is premature to conclude that this precludes their use in COPD management. The use of the ICS/LABA combination is well established and certainly does reduce morbidity in reducing symptoms and exacerbations without excess mortality (TORCH study). I agree that LAMA/LABA combinations are fast becoming the standard of care for many COPD phenotypes given the demonstrable superiority over the ICS/LABAs (FLAME, NEJM 2016). However, patients that have persistent symptoms or exacerbate on dual-bronchodilators should have an inhaled steroid added (GOLD, COPD-X guidelines), which would explain why you see its reasonable and evidence-based use in COPD in the absence of asthma.

          • Jarrod McMaugh

            I think we’re generally in agreement…

            In the first instance i’d treat symptomatically but not make a definitive diagnosis without the provocation test, since the label itself in this case can impact their life as much as the condition.

            In the second instance, ICS as ongoing treatment needs to be reserved for patients in whom LABA/LAMA combination is unable to adequately reduce symptoms and improve quality of life. In all other patients it should be utilised during exacerbations in a stepwise process…. Like an asthma plan (ironically)

  2. Lisa Simpson

    If only spirometry (pre and post bronchodilator) testing is used to diagnose asthma this would not be accurate if asthma isn’t active at the time of testing (active through exposure to current triggers eg spring). I would imagine not all testing would be as comprehensive as it needs to be.

    • Toorisugarino Isha

      That’s an excellent point. I wonder about the quality of the spirometry testing at diagnosis and what proportion of ‘variable efforts’ was misconstrued as postbronchodilator reversibility leading to a potential misdiagnosis of asthma.

      • Jarrod McMaugh

        Are you aware of the criteria for reporting a reversible obstruction based on spirometry?

        If you refer to a qualified technician, you can expect a report that will clearly guide you with regards to confounding factors such as variable effort (if it occurred), poor technique, or other issues caused by patient variance.

        • Toorisugarino Isha

          Perhaps you can enlighten me as to the criteria?

          It isn’t clear from my reading of this JAMA article in what setting the original lung function was performed for the 11.8% without current asthma but who had previous positive testing for asthma.

          My concern is regarding the low quality of compact point of care spirometers, typically seen in GP practices, offering a generic machine interpretation of the lung function without regard for technical factors or artifact. I think all pulmonary function testing should be conducted in a formal respiratory laboratory by a qualified respiratory scientist who can get the best out of patients in terms of technique and minimise variance between efforts.

          • Jarrod McMaugh

            I couldn’t agree more

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