When examining common factors for shared disease exacerbation of asthma and chronic obstructive pulmonary disease (COPD), researchers found 5 distinct clusters that went beyond disease labels.
Asthma and COPD are among complex chronic inflammatory airway diseases that have diverse pathophysiological conditions and clinical symptoms. A new concept, called "treatable traits ," takes into consideration patient characteristics and characteristics, rather than diagnostic labels, to identify the optimal treatment for patients.
"Although asthma and COPD share common mechanisms, the primary approach to treating chronic inflammatory airway diseases has been to first name a diagnosis and then follow the clinical guidelines that correspond to that diagnosis," the authors explained. "This approach, also known as one-size-fits-all medicine, has been reported to have limitations in providing adequate treatment for a variety of conditions that vary from patient to patient."
To clarify exacerbation-prone phenotypes beyond disease labels, researchers performed cluster analyzes of patients with 1 or more exacerbations in the past year despite being treated by a pulmonologist.
The study was published in PLoS ONE and included 117 patients with asthma, 48 patients with COPD, and an additional 37 patients with asthma-COPD overlap (ACO).
All patients had received treatment at the University of Tsukuba Hospital in Japan and/or its affiliated hospitals. The study authors defined exacerbation as the need for an intravenous steroid infusion, either a dose increase or at least 3 days of oral steroid administration, or the use of antibiotics due to worsening of symptoms in the previous year. .
To also understand the role of the rs8832 polymorphism of the IL4RA gene, which is related to type 2 inflammation, in these phenotypes, a control group of 1529 adults without asthma or COPD was included in multinomial logistic analyses. The genetic influence of rs8832 was also evaluated in 130 asthma patients with allergic rhinitis but no history of exacerbation.
The authors identified 5 clusters that were considered to be of “good cluster quality” based on the silhouette indices of cohesion and separation (0.214).
The clusters identified were:
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The authors noted that groups 1 and 3 did not match the disease labels for asthma and COPD. Furthermore, cluster 1 was considered an exacerbation-prone phenotype, particularly associated with eosinophilic airway inflammation.
A significant association was found between group 5 and rs8832 (odds ratio [OR], 3.88; 1.34-11.26, p = 0.013), as well as between the type 2 exacerbation-prone phenotypes and rs8832 for the groups 1 and 5 (OR, 2.73), 1.45-5.15, P = 1.9 × 10−3).
Although genotyping for rs8832 was unsuccessful in some patients in the cluster analysis, multinomial logistic regression analyzes of the G allele of rs8832 showed that it was significantly associated with the high IgE allergic rhinitis group in cluster 5. observed a similar but non-significant trend with the rs8832 allele.
"Our results indicated that the clinical heterogeneity of disease exacerbation may reflect the presence of common exacerbation-prone endotypes in asthma and COPD, and may support the use of the treatable traits approach for the prevention of exacerbations in patients with chronic inflammatory diseases of the respiratory tract". the authors said.
