An attention-grabbing by the Mail Online recently read “”The great asthma myth: A third of those diagnosed don’t have the condition,” thereby birthing the thought that the diagnostic tests for asthma may not be completely accurate and/or reliable.
A study carried out on adults that were previously diagnosed with asthma showed that approximately one-third of the test population showed no observable signs or symptoms of the disease on being retested.
The health implications of asthma cannot be overemphasized, seeing as it can potentiate other illness and may result in death if not managed properly. However, the symptoms are transient, thereby making it difficult for reliable diagnosis to be made at any time.
The study suggested that a major reason why previously diagnosed patients appeared to not actually have asthma could be tied to the kind of diagnostic tests that were carried out on them. They probably did not have objective tests taken of the state of their lungs. About a third of these patients were able to discontinue taking their medications upon re-examination five years after their initial diagnosis. This was done under close medical supervision.
There are existing guidelines in the UK on how a doctor can confirm if a patient’s symptoms are due to asthma or not. The spirometry tests are recommended; a spirometer measures the amount of air that a person breathes in and out of their lungs.
A more comprehensive guideline is being developed to improve on the tests for asthma but the general recommendation is that patients should be started on treatments immediately if the symptoms presented are highly suggestive of asthma.
Asthma attacks can escalate quickly; therefore it is not advisable that a patient reduces their intake of their asthma medication or stops taking their medications without the consent of their doctor. If you are unsure about continuing with your asthma medication, consult your GP.
The origin of the story
The study was funded by the Canadian Institutes of Health Research. It involved the collaborative efforts of researchers from McMaster University, the University of Toronto, the University of Calgary, the University of Manitoba, Dalhousie University, the University of Alberta, Université Laval, the University of British Columbia and the University of Ottawa.Its findings were first published in the Journal of the American Medical Association (JAMA).
The major accusations made by the report include doctors making diagnosis without doing proper asthma tests and also for giving out inhalers to patients indiscriminately.
Considering the fact that the current guidelines recommend spirometry as the diagnostic test for asthma despite its inadequacies, doctors are advised to utilize their clinical skills garnered from years of practice in addition to the various tests prescribed.
Nature of the research
This group study was carried out on groups of adults who had been recently diagnosed of asthma. They were retested for asthma and those who showed no signs of the illness were taken off their asthma medications and closely monitored for a year. The process of diagnosing the patients in the first place was also investigated.
The study was structured to detect patterns in the observations; such as a connection between diagnostic asthma tests and the results of retesting. However, it cannot confidently show that a person who was not diagnosed with spirometry tests did not have asthma. This is one of its limitations.
HOW WAS THE RESEARCH DONE?
Researchers selected 10 Canadian cities as their target area and then contacted several thousands of people in a bid to find out if they had been diagnosed of asthma in the past decade. The persons who met these criteria and who agreed to participate in the study were retested to confirm their initial diagnosis.
Some people’s tests showed no signs of asthma and they had to be assessed by a lung specialist. Some still showed no signs of asthma and their medication was either titrated or stopped, as appropriate. They were monitored for another year for signs of worsening symptoms and also had two tests during the year to monitor/detect asthma.
The first test used was spirometry which measures the amount of air that can be breathed out in one second. The patient is then given a puff from an asthma inhaler and the test is repeated to see if there are changes in the result. If the result improves, it means the person has airflow obstruction, a classic sign of asthma and which can be reversed by giving proper medications. However, other tests were needed if the result for spirometry was negative.
The second test was the bronchial challenge test which involved a person breathing in a chemical called metacholine which narrows the airways. Spirometry tests are then done to see the effect of various doses of the drug on their airways.
For persons who had no signs of asthma, the dose of their asthma medication was divided into two and they had to be retested three weeks later.
For those with normal test results, their medication was stopped completely and they were retested three weeks later.
For persons who had negative results for all the tests, they were assessed by a lung specialist, to see if there was an alternative diagnosis that could explain their initial symptoms. They were further retested after 6 and 12 months.
In a bid to have a full picture of the patient’s condition and history, the doctors who did the initial diagnosis were contacted. They provided information on the process of diagnosis they used and they also supplied the results of the initial tests carried out.
The results were analysed to see the number of persons who could have their asthma diagnosis discarded. They also found differences between confirmed and unconfirmed asthma cases.
THE RESULTS
- 1,026 people were eligible for the study and 613 completed all the required assessments with the result that their asthma diagnosis was either confirmed or discarded.67% (410 people) initial diagnosis was confirmed and 33% (203 people) were ruled out.
- Of the persons who had asthma ruled out, only one-third of them had been taking asthma medicines everyday while 79.3% used their medication sometimes.90% of the people with a confirmed diagnosis used their medications occasionally while 50% used theirs every day.
- 28 persons were not diagnosed with tests initially but the diagnosis was confirmed by a specialist while only 86 people were confirmed by the initial tests carried out.The 203 people who had asthma ruled out had alternative diagnoses that included acid reflux and rhinitis. 12 people had cardiovascular diseases that were misdiagnosed whole 61 people had no symptoms of difficulty in breathing at all.
It was likely that people who had their diagnosis ruled out had been diagnosed without spirometry tests. 55.8% of those who had their diagnosis confirmed haveinitial spirometry tests while only 43.8% of those who had their diagnosis ruled out had had any airway tests at diagnosis.
INTERPRETATION OF RESULTS
The researchers came up with two interpretations: people were either misdiagnosed or their symptoms had abated between initial diagnosis and the retest. The latter was feasible because test results show that asthma symptoms may be transient, they report. Nevertheless, the result from their study proposes that “misdiagnosis of asthma may occasionally occur in the community”.
One of the setbacks they report in the course of the study was the 24% of doctors who declined to provide information about the initial diagnosis. Therefore, it was “impossible to determine whether the initial diagnostic workup [initial assessment by their doctor], and hence the initial diagnosis of asthma in these participants, were appropriate”.
The implication is that the researchers do not know the extent to which results were influenced by expected fluctuations in asthma symptoms or initial diagnosis.
Conclusion
Results of this cohort study show that having been diagnosed with asthma does not always mean that you have to continue taking asthma medications for the rest of your life.
There are some limitations to the study. The study was carried out in Canada which has different health practices from the UKK, thus the results may not be strictly applicable to the UK.
In addition, the people who participated in the study may not be truly representative of the entire population of persons with asthma seeing as some persons who were invited to participate in the study declined.
Furthermore, some doctors did not provide records of diagnosis, so there is no actual figure for the number of persons who had initial asthma tests.
One-third of the people without asthma obviously did not have current asthma symptoms for the sole reason that they were not on daily medication.
The guidelines in the UK recommend that people on asthma medications should be reassessed regularly to ensure they do not keep using more medications than they need. Some persons may be able to reduce their medication intake and then discontinue the medication completely without medical supervision. However, this is not something that should be done without professional advice because asthma attacks can be life-threatening.
Spirometry tests and others like it may help with diagnosis, but they are not ironclad.
It is expected that the National Institute for Health and Care Excellence (NICE) will come up with new regulations regarding how diagnosis of asthma should be carried out.Spirometry is currently the test of choice but a normal result does not mean asthma can be ruled out. There is a need for further tests to be carried out to confirm the diagnosis.
If you have questions about the effectiveness of your medication, you should consult your GP. They will reassess your symptoms and come up with the best management options for you.
