Asthma exacerbation risk persists despite maintenance adherence, disease severity
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LOUISVILLE, Ky. — Patients with asthma faced high risks for exacerbations despite their maintenance medication or disease severity, reported researchers at the American College of Allergy, Asthma & Immunology Annual Scientific Meeting.
“Patients with asthma have worsening symptoms that are likely related to both underlying inflammation and bronchoconstriction,” Njira L. Lugogo, MD, director of the asthma program in the division of pulmonary and critical care medicine at University of Michigan, said during her presentation.
Clinicians should broadly consider concomitant symptom treatment via a fast-acting bronchodilator and an inhaled corticosteroid (ICS) to mitigate the increasing airway inflammation that leads to asthma exacerbations, according to the researchers.
Typically, Lugogo said, patients depend on short-acting beta agonists (SABA) for rapid relief of symptoms.
“Increased SABA exposure, however, increases the risk of severe exacerbations independent of maintenance therapy, and maintenance anti-inflammatory therapy does not eliminate exacerbation risk,” Lugogo said.
Previous data from the MANDALA study has found a decrease in exacerbation risks among patients with uncontrolled moderate to severe asthma on maintenance medication when using fixed-dose ICS-SABA combination therapy compared with as-needed SABA monotherapy, according to study background information.
To assess the broader applicability of these MANDALA results, researchers examined the administrative claims of 351,870 patients aged 12 years and older who received SABA for asthma between 2010 and 2017. Using maintenance fills as a proxy for asthma severity, researchers stratified patients by SABA fill patterns as well controlled (31.1%), not well controlled (34.7%) or very poorly controlled (34.2%).
The researchers also assessed adherence to maintenance therapy based on medication possession ratio (MPR), with 63.9% having an MPR of less than 50%, 23.1% of patients with an MPR of 50% to 79%, and 13% with an MPR of 80% or higher.
“Two-thirds of patients had a medication possession ratio of less than 50%, indicating overall poor adherence with background therapy,” Lugogo said.
Maintenance medications included leukotriene modifiers (32.5%), medium-dose ICS long-acting beta agonists (LABA; 20.3%), high-dose ICS-LABA (14.4%), low-dose ICS (13%), medium- or high-dose ICS (10.5%) and low-dose ICS-LABA (6.9%).
Across the study, 48.8% of patients experienced one or more severe asthma exacerbations, including 44.8% of those with well-controlled asthma, 48% of those whose asthma was not well controlled and 53.2% of those with very poorly controlled asthma (P < .0001).
Adherence to maintenance therapy did not appear to consistently affect the risk for severe exacerbation among the patients with controlled vs. not well-controlled asthma, Lugogo continued.
Specifically, 47.6% of patients with 80% or greater MPR, 50.5% of those with 50% to 79% MPR and 48.4% of those with less than 50% MPR experienced one or more severe exacerbations (P < .0001).
But among the patients with very poorly controlled asthma, she continued, patients with at least 80% MPR were significantly less likely to experience one or more severe exacerbations than those with less adherence.
“Patients with better asthma control and higher adherence had significantly less exacerbations,” Lugogo said. “However, even those with greater than 80% maintenance adherence did not have complete exacerbation elimination.”
Between 36% and 54% of patients with well-controlled asthma and at least 80% MPR still had high rates of exacerbations, the researchers found.
Many patients with asthma are at high risk for exacerbations regardless of their asthma control medication or their disease severity, the researchers concluded.
“Treating symptoms that occur surrounding exacerbations with a fast-acting bronchodilator and an ICS may be considered broadly to mitigate rising airway inflammation that leads to asthma exacerbations,” Lugogo said.