Identifying an At-Risk Asthma Phenotype: Allergy and Recurrent Infections Predict Severe Disease

Area of Science:

• Immunology
• Pulmonology
• Epidemiology

Background:

• Asthma severity is influenced by complex immunologic and environmental factors.
• Allergic asthma is linked to increased susceptibility to respiratory infections.
• The combined role of allergy and antibiotic-treated infections in severe asthma progression requires evaluation.

Purpose of the Study:

• To evaluate the association between allergic asthma and recurrent respiratory infections (RRI) requiring antibiotics.
• To determine if these factors increase the risk of developing severe asthma.

Main Methods:

• Registry-based cohort study using Swedish national data (2014-2019).
• Identified mild-to-moderate asthma patients (2014) with allergic asthma defined by anti-allergic medication prescriptions.
• Defined RRI by ≥2 antibiotic prescriptions for lower respiratory tract infections (2015-2016).
• Assessed severe asthma development (2017-2019) using ERS/ATS criteria.

Main Results:

• 21.8% of 113,393 patients had allergic asthma; RRI was more frequent in allergic asthma (7.5% vs. 5.9%).
• 0.77% developed severe asthma; incidence was highest in patients with both allergic asthma and RRI (2.0%).
• Patients with both allergic asthma and RRI had a 3.47-fold increased risk of severe asthma, consistent after adjustments.

Conclusions:

• Allergic asthma and antibiotic-treated respiratory infections are independent and additive predictors of severe asthma.
• These findings identify a clinically actionable risk profile for severe asthma.
• Results may inform targeted preventive strategies in asthma management.