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.”