Another look at overdiagnosis/remission of asthma


I appreciated the PURL, “Should you reassess your patient’s asthma diagnosis?” (J Fam Pract. 2018;67:704-707) that reminded clinicians to taper asthma controller medications in asymptomatic patients. The articles cited1,2 by Drs. Stevermer and Hayes documented that one-third of the adults enrolled in the respective study with physician-diagnosed asthma did not have objective evidence for asthma and were either over-diagnosed or had remitted. These articles also contained evidence that: 1) over-diagnosis was likely much more common than remission,1 and 2) there was a significant temporal trend towards increasing over-diagnosis/remission during the last several decades. The authors of the cited article1 suggested that the temporal trend could be explained by increased public awareness of respiratory symptoms, more aggressive marketing of asthma medications, and a lack of objective measurement of reversible airway obstruction in primary care. These assertions deserve careful consideration as we strive to diagnose asthma appropriately.

Over-diagnosis/remission is almost certainly not as prevalent (33%) as the authors of the cited articles1,2 reported. The reason is simple selection bias: 1) the cited study2 excluded asthma patients who smoked >10 pack-years (it enrolled 701 asthma patients and excluded 812 asthma patients with a >10 pack-year smoking history), and 2) this study likely did not include asthma patients with the asthma-COPD overlap syndrome, which is treated as asthma and comprises an additional 30% of our patients with chronic airflow limitation (the asthma-COPD spectrum).3 Asthma patients who smoke and/or have the overlap syndrome are prone to severe asthma that is refractory to inhaled corticosteroids.3,4

In addition to making the correct diagnosis, it is equally important to be aware of efficacious therapies for severe refractory asthma that primary care clinicians can easily use. There is now good evidence that azithromycin is efficacious for severe refractory asthma5 and should be considered prior to referral for immunomodulatory asthma therapies.6

David L. Hahn, MD, MS
Madison, Wis

1. Aaron SD, Vandemheen KL, Boulet LP, et al; Canadian Respiratory Clinical Research Consortium. Overdiagnosis of asthma in obese and nonobese adults. CMAJ. 2008;179:1121-1131.

2. Aaron SD, Vandemheen KL, FitzGerald JM, et al; Canadian Respiratory Research Network. Reevaluation of diagnosis in adults with physician-diagnosed asthma. JAMA. 2017;317:269-279.

3. Gibson PG, Simpson JL. The overlap syndrome of asthma and COPD: what are its features and how important is it? Thorax. 2009;64:728-735.

4. Stapleton M, Howard-Thompson A, George C, et al. Smoking and asthma. J Am Board Fam Med. 2011;24;313-322.

5. Gibson PG, Yang IA, Upham JW, et al. Effect of azithromycin on asthma exacerbations and quality of life in adults with persistent uncontrolled asthma (AMAZES): a randomised, double-blind, placebo-controlled trial. Lancet. 2017:390659-668.

6. Hahn DL, Grasmick M, Hetzel S, et al; AZMATICS (AZithroMycin-Asthma Trial In Community Settings) Study Group. Azithromycin for bronchial asthma in adults: an effectiveness trial. J Am Board Fam Med. 2012;25:442-459.

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