Clearing the Air

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Illustration of someone using an inhaler

Too many patients are being diagnosed with asthma and Chronic Obstructive Pulmonary Disease (COPD) without first receiving lung function testing.

Choosing Wisely Canada has launched a campaign reminding physicians that the diagnosis of these conditions requires lung function testing, starting with a simple spirometry and bronchodilator response test.

Asthma and COPD are among the most common chronic diseases in Canada — approximately 11 percent of the Canadian population carry a diagnostic label of asthma and six percent a label of COPD. However, more often than not, both conditions are diagnosed based on symptoms and physical exam findings rather than with objective testing.

What are the barriers to pulmonary function testing? And how might clinicians and patients be supported to avoid overtreatment? Those questions were the focus of a recent webinar launching Choosing Wisely Canada’s Lets Clear the Air campaign.

Dr. Samir Gupta, a respirologist and clinician-scientist at the Li Ka Shing Knowledge Institute of St. Michael’s Hospital and an Associate Professor in the Department of Medicine at the University of Toronto, began the webinar by explaining the magnitude of the problem. In Canada, 33 percent of patients diagnosed with asthma by a physician in the last five years did not have objective evidence of asthma on lung function testing. However, 79 percent of these patients without asthma were using asthma medications.

Patients who are incorrectly diagnosed with asthma may receive unnecessary treatment, resulting in possible medication side effects and avoidable costs while their actual diagnoses go overlooked, resulting in ongoing symptoms and diagnostic delays, said Dr. Gupta. Asthma mimickers include allergic/non-allergic rhinitis with post-nasal drip; gastro-esophageal reflux disease; anxiety disorders and some serious cardiopulmonary conditions

As with asthma, studies show that 31 to 44 percent of patients who received a clinical diagnosis of COPD did not actually have the condition when tested objectively, said Dr. Gupta.

When COPD is diagnosed without spirometry, providers underestimate the severity of the condition. Accordingly, providers prescribe more appropriate (evidence-supported) medications for patients with suspected COPD when they have undergone spirometry. As a result, patients with COPD have both lower hospital admission rates and lower mortality when the diagnosis is confirmed by spirometry, as opposed to clinically.

Both asthma and COPD can be challenging to diagnose and assess based on history and physical examination alone, said Dr. Gupta. There are no individual questions or combinations of questions accurate enough to render a high-likelihood diagnosis of either condition. Physical examination also has a limited diagnostic role in each condition.

“That old adage — all that wheezes is not asthma (or COPD) — is true,” he said, “and for that reason, we need the objective testing to tell us more.”

The problem is that spirometry is not used often. Only 43 percent and 36 percent of Canadian patients who receive a diagnostic label of asthma and COPD, respectively, have had pulmonary function testing within 1 year before or after the time of diagnosis

The barriers to the use of lung function testing in patients with suspected asthma or COPD are many, Dr. Suzanne Levitz, a family physician at Montreal’s Mount Sinai Hospital, told the webinar. Some clinicians, she said, have access to in-office spirometry, but without trained personnel to conduct spirometry, high-quality testing is difficult to achieve. Interpreting results can also be challenging.  

To help with this, the Lung Health Foundation has developed educational webinars and modules on spirometry. Visit Choosing Wisely Canada for more information.

Staff performing in-office testing should also have greater access to training and maintenance-of-certification programs (e.g., through subsidies). An example of such a course is the online RESPTREC course.

Alternatively, many clinicians send their patients to an outside lab for spirometry. Availability of outside labs varies widely by region, often resulting in diagnostic delays. If testing is not readily available, it may be reasonable to initiate therapy in a symptomatic patient prior to lung function testing, said Dr. Levitz. It is critical, however, to order lung function testing at the same time so that the diagnosis can be definitively confirmed, she said. Some patients may refuse lung function testing in a lab due to travel and inconvenience. To help address this, Choosing Wisely Canada has developed a wide-ranging patient-facing campaign to try to convey the importance of objective testing to the public.

“I would urge family physicians to let their patients know about the great resources developed by the campaign so that, all together, we can work towards making a better diagnosis, prescribing the right medications at the right time and taking away medications that may not be required,” said Dr. Levitz.