COMMENTARY

Diagnosing Severe Asthma: 'Not as Easy as It Sounds'

Aaron B. Holley, MD, FCCP

Disclosures

May 16, 2018

Editorial Collaboration

Medscape &

Good morning. My name is Dr Aaron Holley. I am chief of pulmonary and critical care medicine at the Brooke Army Medical Center in San Antonio, Texas. This morning, I am speaking to you as part of the collaboration between Medscape and CHEST [American College of Chest Physicians], and I will be talking about severe asthma.

Only about 3%-10% of all asthmatics are classified as severe.[1] Although this does not sound like that many, they account for 60% of all asthma costs. These costs rival those for very resource-intensive diseases like type 2 diabetes, chronic obstructive pulmonary disease, and cerebrovascular accidents.[1]

Diagnosing Severe Asthma

The diagnosis of severe asthma starts with confirming the asthma diagnosis. That is not as easy as it sounds. Lots of patients get a label of asthma based on symptoms—without any objective testing—and we can spend quite a bit of time trying to treat them when, really, they have a [different] diagnosis.

Objective testing is needed before you go down the pathway of trying to find severe asthma. Objective tests include bronchoprovocation testing, usually with an agent such as methacholine; or bronchodilator testing, where you do spirometry before and after you give the patient a bronchodilator, to test for any response in the airways. You can also give your patient a peak flow meter; have them do peak flows at home and assess for variability over time. You really need to make sure that you have the right diagnosis.

Once you have the right diagnosis, and before you even consider severe asthma, the next step is to make sure you have good medication adherence and that all comorbid diseases have been addressed. Both of these are really difficult to do. Medication adherence, particularly for the elderly, is critical. Proper inhaler technique is also a big deal. Inhalers are not easy. You have to time them correctly in order to get the medicine into your lungs and get good deposition throughout the entire respiratory system. In addition, we often give patients multiple different brands of inhalers from different companies and with different delivery mechanisms. This further complicates things. Good adherence and proper technique are critically important before you decide that a patient is not responding to the therapies you are giving.

Asthma is very common and there are a lot of common comorbid diseases that run with it. The big one is rhinosinusitis. It's a big problem with asthma and it worsens asthma control. All psychosocial issues (eg, stress, fatigue, depression, anxiety) can worsen asthma control. You can throw lots of inhalers at your patient, but unless you are helping them with symptom perception and properly managing their psychosocial issues, you may not get the outcomes you are looking for. Other comorbid diseases to think about include gastroesophageal reflux disease, vocal cord dysfunction, obesity, smoking and smoking-related diseases, ongoing environmental exposures (exposures to allergens in the home, at work, or at some other place that the patient frequents), hyperventilation syndrome, and sleep apnea.[1] The list is long, and all of these things can have an impact on asthma control and the way your patient perceives their asthma symptoms.

ERS/ATS Guidelines for Diagnosing Severe Asthma

We diagnose severe asthma on the basis of the European Respiratory Society (ERS)/American Thoracic Society (ATS) guidelines.[2] They mandate that you get that objective diagnosis first and assess for medication adherence, proper inhaler technique, and comorbidities. Once you have done that, you consider the diagnosis of severe asthma if your patient is not responding.

Before you diagnose your patient with severe asthma, the guidelines recommend that you get your patient to an asthma specialist. That usually means an allergist/immunologist or a pulmonologist. Once you do, the asthma specialist will probably evaluate medication adherence technique, check comorbidities, and reestablish the objective diagnosis before considering a diagnosis of severe asthma.

Once you have addressed all of the things I talked about (medication adherence, objective diagnosis, and comorbid diseases), you can consider a severe asthma diagnosis. The ERS/ATS guidelines say, "[S]evere asthma is defined as asthma that requires treatment with high-dose inhaled corticosteroids plus a second controller and/or systemic corticosteroids to prevent it from becoming 'uncontrolled' or that remains 'uncontrolled' despite this therapy." The guidelines go on to state that the diagnosis must be confirmed by an asthma specialist and that treatment must be conducted by an asthma specialist for at least 3 months before the diagnosis of severe asthma can be confirmed.

When you boil it all down, severe asthma is when you have ruled out any other causes of your patient's symptoms, they have an objective diagnosis of asthma, and they are just not responding to standard inhaler and controller therapies.

After Diagnosis, What Comes Next?

Once you have sent them to the asthma specialist, what happens next? Here is where things get pretty exciting. There have been a lot of advances in this field over the past 10 years or so.

We are getting much better at using clinical factors to phenotype asthma—understanding whether it is eosinophilic, neutrophilic, or paucigranulocytic—in order to predict which therapies patients are likely to respond to. This is not an easy thing to do, but we are going to get a lot better at it over the next few years.

Once you have done what you can to phenotype your patient, you can consider other types of asthma therapy. There are controller therapies and antibodies targeted at specific inflammatory immunomodulators (eg, anti-immunoglobulin E, anti-interleukin-5). We use bronchial thermoplasty in specific patients we think are going to benefit. We have good efficacy data for all of these therapies in the right patient population. Other things can be tried, such as macrolide agents, antifungal therapies, and long-acting muscarinic antagonists (LAMAs). All of these are going to have a role for the patient with severe asthma when standard therapies are just not cutting it.

Phenotyping and using expensive injectable medications and treatments are really hard and very complicated. Again, it is important that your patient go to an asthma specialty clinic so that the asthma specialist can treat their severe asthma.

That concludes my quick overview of severe asthma. This is Dr Aaron Holley.

Suggested Reading

Gibeon D, Heaney LG, Brightling CE, et al; British Thoracic Society Difficult Asthma Network. Dedicated severe asthma services improve health-care use and quality of life. Chest. 2015;148:870-876.

Hanania NA. Targeting airway inflammation in asthma: current and future therapies. Chest. 2008;133:989-98.

Laxmanan B, Egressy K, Murgu SD, White SR, Hogarth DK. Advances in bronchial thermoplasty. Chest. 2016;150:694-704.

O'Byrne PM, Pedersen S, Schatz M, et al. The poorly explored impact of uncontrolled asthma. Chest. 2013;143:511-523.

Papi A, Caramori G, Adcock IM, Barnes PJ. Rescue treatment in asthma: More than as-needed bronchodilation. Chest. 2009;135:1628-1633.

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