For the past several years, the trend has been to use inhaled corticosteroid(ICS) early and often for patients with asthma. And now the 2019 Global Initiative for Asthma (GINA) guidelines recommend using ICS as first-line therapy (step 1) as needed). This change is sure to increase ICS use even more.
The logic behind using ICS early and often is sound, but when it comes to asthma, nothing is simple. The first problem is that asthma is overdiagnosed (some estimates put the rate as high as 30%-35%). Even when the diagnosis is correct, up to 50% of patients with the disease will have a noneosinophilic, non-type 2 phenotype that is less likely to respond to ICS. Both scenarios leave physicians chasing symptoms with higher and higher doses of ICS.
So what?” you might say. ICS is safe, and there is minimal systemic absorption. Better to ensure that all asthmatics have ICS on board and risk overtreating than to withhold therapy from someone who needs it. The problem is, ICS is not risk-free. Furthermore, the risk-benefit skews further toward adverse effects, even in those who benefit from treatment, as the dose is increased. A recent review estimates that over 90% of efficacy is achieved at the “lowest” ICS dose As the dose is increased, the incremental benefit is minimal, while side effects increase in a linear fashion.
Patients with mild disease are particularly problematic. They make up the majority (50%-75%) diagnosed with asthma, and they are the group most likely to be affected by the changes to step 1 in the GINA guidelines. A recent study found high rates of noneosinophilic asthma in this group and response to ICS that wasn’t better than to placebo.
The “early and often” approach to ICS is fine. It should come with an important caveat, though. If your patient isn’t responding and you find yourself escalating ICS dose for persistent symptoms, make sure you have the right diagnosis. Once you’ve confirmed you do, take a look at the patient’s serum eosinophil count and ensure that you have the right asthma phenotype. If in doubt, find a good pulmonologist to refer the patient to.
Author : Aaron B. Holley, MD
Source : https://www.medscape.com/viewarticle/915649