Asthma affects 5% of the general population, and severe asthma affects 3% to 10% of that 5%. Severe asthma is responsible for most hospital admissions in cases of asthma. The health-related costs incurred by people with severe asthma are even greater than those of type two diabetics, stroke victims, or COPD patients.
Severe asthma is difficult to treat, especially in the face of comorbidities or among patients that face constant allergen exposure. Among the asthmatic population, 24% will require high intensity treatment, 17% will have difficult-to-treat asthma, and 3.7% will be severe asthmatics. The treatments on offer vary according to the type of difficult or severe asthma that is present.
Once one makes the diagnosis of asthma, it is important to see whether there are confounding factors that are making their asthma worse. Are they using the correct inhaler technique? Do they take the medications they are prescribed, and do so regularly? Are they employed in an occupation that involves continual exposure to allergens? 80% of the time, a patient’s condition can be improved simply by paying attention to measures like these.
To suss out whether patients are adhering to their medication, don’t confront them. Rather ask: “What did you take this morning?” or “What are you using every day?” This approach will be much more effective. Inhaler use is a major problem for asthmatics and a recent study showed that there were use errors in 32% to 38% of dry powder inhalers and 24.9% of metered dose inhalers.
So how does one accurately diagnose asthma and severe asthma? Most patients will be able to identify a few triggers such as petrol, perfumes, grass, or stress. They find that their attacks start with a cough, chest tightness and shortness of breath. They are definitely asthmatic if you use spirometry and identify that forced expiratory volume in one second over the forced volume capacity is less than 70%, and that they have at least a 12% or 200ml increase in FEV-1 after the use of a bronchodilator.
It is ideal to do spirometry while the patient is symptomatic because an asthmatic who is not symptomatic, will have normal spirometry when you test them. If you still suspect asthma and they have normal spirometry, you can get the patient to walk up and down a couple of flights of stairs (for example), wait 5 to 10 minutes, and then repeat spirometry. You may then find a decrease in their FEV-1. The gold standard though, is to do a methacholine challenge test.
This involves giving small doses of methacholine that are titrated in small amounts and increasing the amount gradually to provoke a drop in forced expiratory volume in 1 second by 20%. You could also send them home with a peak flow metre and look for 20% variability during the day if it's still non-reversible.
The above is a highly condensed version of a portion of Dr Peter’s talk. To listen to the entire webinar and earn 1 General CPD point, please visit https://bit.ly/41tEsyq.