Asthma Diagnosis: Time to Review?

Girl (7-9) using inhaler, outdoors

By Martina M. McGrath, MD
January 26, 2017

Asthma is characterized by chronic airway inflammation leading to expiratory airflow limitation, associated with dyspnea, wheeze, and cough. Its course is variable with spontaneous remissions, and diagnosis can be challenging. Current recommendations advise that once stably controlled for three months, patients should undergo medication taper to find the minimum maintenance medication effective at keeping symptoms under control.1 Furthermore, several studies have reported failure to confirm asthma in a subset of physician-diagnosed cases.2 In this vein, a Canadian group recently published a study examining if asthma-controlling medications can be safely stopped in patients with physician-diagnosed asthma.

Participants who had been diagnosed with asthma within the previous five years were recruited from the general population. Using a detailed algorithm, participants underwent serial testing to diagnose airway hyperresponsiveness using changes in FEV1, measured by spirometry pre- and post-albuterol inhalation, and bronchial challenge testing with methacholine. Participants with negative testing underwent a stepwise reduction in inhaled corticosteroids and bronchodilators. After three weeks off medication, stable patients were classified as not having asthma. They were then followed and assessed for alternative diagnosis. Asthma medications were held and repeat challenges were checked at 6 and 12 months.

Six hundred and thirteen patients underwent complete evaluation. While 62.3% were confirmed to have asthma; in 203 patients (33.1%), current asthma was ruled out. A further 2% of enrollees were given an alternative cardiorespiratory diagnosis, including ischemic heart disease, pulmonary hypertension, interstitial fibrosis, and sarcoidosis. At 12-month follow-up, 181 patients were free of symptoms and still had negative testing. Twenty-two of the 203 patients had a positive bronchial challenge test; sixteen of which were asymptomatic and not restarted on medications. Six had symptoms and resumed asthma treatment.

Baseline characteristics showed some notable differences. As might be expected, those without asthma had fewer symptoms and were less likely to be compliant with daily medications. Fewer patients without asthma had undergone formal evaluation i.e., spirometry, bronchial challenge testing or serial measurement of peak flow, at the time of diagnosis. And 55.6% of those with asthma were fully tested as compared to 43.8% of those without asthma.

What conclusions can be drawn from this report? It appears that up to one third of patients diagnosed with asthma within the previous five years may experience remission and can be safely weaned from medications, albeit in a carefully monitored setting. Several of the findings emphasize the relapsing and remitting nature of the disease. Despite appropriate testing at the time of initial diagnosis, many patients had negative testing and no symptoms when reassessed later. Also, a handful of patients in whom asthma was excluded needed to be restarted on meds at 12-month follow-up. This demonstrates the need for continued follow up for these patients and reassessment when symptoms recur. CDC estimates from 2014 report that 7.4% of the adult US population has a diagnosis of asthma.3 If applicable across the population, the findings of this report could have major implications for health care use in a sizable proportion of these patients.


Study the mechanisms, triggers, and treatment of asthma and other allergies in an online cme course from Harvard Medical School: Treating Respiratory and Drug Allergies .


References:

  1. Global Initiative for Asthma. Global strategy for asthma management and prevention. 2016. http://www.ginasthma.org (Accessed 01/23/17)
  2. Heffler E et al. Prevalence of over-/misdiagnosis of asthma in patients referred to an allergy clinic. J Asthma. 2015;52(9):931-4
  3. Aaron SD et al. Reevaluation of diagnosis in adults with physician-diagnosed asthma. JAMA 2017 Jan 17; 317:269. (http://dx.doi.org/10.1001/jama.2016.19627)
  4. https://www.cdc.gov/asthma/most_recent_data.htm (Accessed 01/23/17)

Headshot of Dr. McGrathDr. Martina McGrath is an Instructor in Medicine at Harvard Medical School, and a member of the Renal Division, Department of Medicine, at Brigham and Women’s Hospital, both in Boston. Dr. McGrath is the Medical Editor for the Trends in Medicine blog.

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