Asthma-COPD Overlap Not a Primary Driver of Asthma Exacerbations or FEV1 Decline

While patients with asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) may have a greater symptom burden than those with asthma alone, the presence of ACO was not an independent risk for exacerbations or decline in FEV1 in a new cohort study.¹

“Particularly in severe asthma, only a few studies have focused on the epidemiology and clinical characteristics of ACO. Understanding the influence of COPD features in severe asthma on the clinical course is highly necessary for optimal management and better prognosis,” lead investigator Miho Wakazono, Department of Respiratory Medicine, Faculty of Medicine, Hokkaido University, Sapporo, Japan, and colleagues wrote.¹

Wakazono and colleagues evaluated data from 127 patients with severe asthma from 30 hospitals and clinics that were ensured to have favorable treatment adherence. The investigators assessed the prevalence of ACO using the Japanese Respiratory Society ACO criteria and categorized patients into 2 groups, ACO and non-ACO, and compared their clinical characteristics. They evaluated exacerbation rates with a 3-year follow-up as well as the annual change in FEV1 with a 5-year follow-up of 105 participants. They also analyzed exacerbation-free rate using the Kaplan–Meier method and the Cox proportional hazards model.

The investigators found that the prevalence of ACO in severe asthma was 31.5% and those with ACO were older, more frequently male, and had a longer duration of asthma than those without. Notably, they did not find any significant differences in exacerbation rates between the ACO (62.2%) and non-ACO groups (63.2%; P = .91) or the annual change in FEV1 (−39.2 mL/year vs. −31.2 mL/year; P = .11).¹

“In conclusion, this prospective multicenter study on severe asthma under treatment demonstrated that approximately 30 % of patients met the JRS criteria for ACO. The ACO group showed similar frequencies of exacerbations and annual declines in FEV1 compared with the non-ACO group. These findings imply that the diagnosis of ACO may not be significantly associated with an unfavorable outcome in patients with well-controlled severe asthma. Overall, gaining a better understanding of the pathophysiology of ACO and its impact on outcomes, and assessing treatable traits such as FeNO, may be more important in asthma management than determining the presence of ACO,” Wakazono and colleagues concluded.¹

A factor that does affect asthma control in both children and adults is HbA1c levels, as further supported by recent research. The AIRWEIGHS Study enrolled 164 children with asthma from Baltimore, Maryland, with an average age of 11 years (standard deviation [SD], 2), who were predominately African American (85%) and were mostly male (59%). Participants also had predominantly moderate or severe asthma by NAEPP criteria (59%), had households with an income below $34,999 (60%), were publicly insured (83%), and were overweight/obese (61%). Of the 164 participants, 52 were excluded from the analysis due to unsuccessful blood draws or participant refusal. Twenty of the remaining 112 (18%) had HbA1c measurements of at least 5.7%.²

Investigators found that increased HbA1c levels were associated with an increase in the Asthma Therapy Assessment Questionnaire, indicating worse asthma control (β, 0.74; P <.05). Furthermore, interaction analysis revealed that BMI percentile had a significant interaction with HbA1c, with HbA1c having a stronger association with maximum symptoms days and exacerbation risk among children with lower versus higher BMI percentile values.²

REFERENCES

1. Wakazono M, Kimura H, Tsujino I, et al. Prevalence and clinical impact of asthma-COPD overlap in severe asthma. Allergol. Int. 2025; 74(2): p 308-315. Doi: 10.1016/j.alit.2024.11.003

2. Pham H, Koehl R, Woo H, Wu TD, Qiu AY, Brigham EP, Hansel NN, McCormack MC. Association Between Hemoglobin A1c and Pediatric Asthma Control. J Asthma Allergy. 2025;18:649-654. Doi: 10.2147/JAA.S498269