The main strength of the study was the inclusion of all omalizumab-treated patients from a tertiary referral asthma centre covering one million inhabitants aged ≥ 15 years, and not least the manual validation of all data from EPJ, including the asthma diagnosis, sensitisation to perennial aeroallergens, omalizumab treatment, IgE level, BMI, and smoking status. Here, IGHE is linked to asthma.