Previous asthma diagnosis may no longer be accurate in adults
A substantial proportion of adults with previously physician-diagnosed asthma may not have a current diagnosis, due possibly to spontaneous asthma remission or to misdiagnosis of asthma in the community, study authors wrote.
Many adults previously diagnosed with asthma may no longer fit the criteria for a current diagnosis of the disease, according to a recent study.
Researchers performed a prospective multicenter cohort study in 10 cities in Canada from January 2012 to 2016 to help determine whether asthma could be ruled out and asthma medications safely withdrawn in adults who had previously been diagnosed with asthma. Adults with a history of physician-diagnosed asthma during the past five years were recruited using random-digit dialing, and information on how asthma was originally diagnosed was obtained from the diagnosing physicians. Patients who were currently using long-term oral steroids and those who couldn't be tested with spirometry were excluded from the study.
Home peak flow and symptom monitoring, spirometry, and serial bronchial challenge tests were used to assess study participants, and daily asthma medications were gradually tapered over four study visits in all patients who were taking them. Repeated bronchial challenge tests were performed over one year in patients whose diagnosis of asthma was ruled out. The study's primary outcome measure was the proportion of patients whose current asthma was ruled out, that is, those who showed no evidence of acute worsening of asthma symptoms, reversible airflow obstruction, or bronchial hyperresponsiveness after withdrawal of all asthma medications and after establishment of an alternate diagnosis by a study pulmonologist. The proportion of patients in whom asthma was ruled out after 12 months and the proportion who had an appropriate initial diagnostic workup for asthma in the community were secondary outcomes. The study results were published online Jan. 17 by JAMA.
A total of 701 participants were included in the study. Most (67%) were women, and the mean age was 51 years. Of these, 613 participants completed the study and underwent a conclusive evaluation for a current asthma diagnosis. Five hundred thirty-one (86.6%) reported that they had used asthma medications recently, and 273 (44.5%) reported that they used asthma-controlling medications (inhaled corticosteroids and/or antileukotriene medications) daily. In 203 of the 613 participants (33.1%; 95% CI, 29.4% to 36.8%), current asthma was ruled out, and in 12 participants (2.0%), serious cardiorespiratory conditions that had been misdiagnosed as asthma were detected. One hundred eighty-one participants (29.5%) continued to have no clinical or laboratory evidence of asthma after another 12 months of follow-up. Testing for airflow limitation at the time of the initial asthma diagnosis was more likely in participants whose asthma was confirmed than among those in whom it was ruled out (55.6% vs. 43.8%; absolute difference, 11.8% [95% CI, 2.1% to 21.5%]).
The authors noted that some participants could have had recurrence of asthma after the 15-month period covered by the study and that the study could have included more patients with milder asthma since those on current long-term corticosteroid therapy were excluded. Among other limitations, they pointed out that bronchial challenge tests do not have 100% sensitivity for detecting asthma. However, they concluded that a substantial proportion of adults with previously physician-diagnosed asthma may not have a current diagnosis, due possibly to spontaneous asthma remission or to misdiagnosis of asthma in the community. They suggested that reassessment of asthma diagnoses in this population may be warranted.
The authors of an accompanying editorial noted that the current study does not suggest that bronchial challenge testing should be used to guide medication tapering in clinical practice and stressed that asthma controller medications should still be adjusted on the basis of ongoing monitoring, including interval spirometry. They also pointed out that it is still unclear whether demonstrating resolution of asthma is distinct from tapering asthma control medications that are found to be no longer needed. “From a clinical perspective, either scenario requires availability of a short-acting bronchodilator as needed and the ongoing monitoring of asthma control, including the use of physiological measures of airflow limitation,” the editorialists wrote. In addition, they wrote, the current study “is an important reminder that in addition to reviewing asthma symptoms and treatment, trying to understand if the diagnosis of asthma is still appropriate is an important part of clinical care.”