Background: Difficult to treat asthma involves uncontrolled asthma despite high doses of inhaled drugs. Patients are redirected to a tertiary institution where multidisciplinary treatment (MDT) is carried out. Common causes of poorly controlled asthma are incorrect inhaler technique and poor adherence to treatment. Addressing these factors is an asthma nurse specialist (ANS)'s important task. 

Objectives: The aim of this study was to assess which factors that could be addressed by ANS affect uncontrolled asthma.

Method: We analyzed patients who were admitted as difficult to treat asthma for MDT management from January 2021 to November 2022 at University Clinic Golnik.

Results: Of 89 patients, 47 were males, the median age was 54.4 years. We found that in 65.8%, the cause for difficult to treat asthma was incorrect inhaler technique. The most common mistakes were inhaling too fast/too short (54,3%), irregular exhalation before inhalation (40%), poor coordination (4,3%) or incorrect placement of the inhaler into the mouth (1,4%). Poor adherence was established at 34,5%. Smoking cessation was advised in 13,4% smokers. During follow-up, we confirmed severe asthma in 14 patients who were eligible for biologics.

Conclusion: The main cause of uncontrolled asthma was incorrect inhaler technique, followed by poor adherence and smoking. The most common mistake in the inhaler technique was inhaling too fast. All these factors could be addressed by ANS. With high expertise, ANS has a crucial role in MDT by enabling patients to get the knowledge and skills with which they can keep asthma under control.