Aim and objectives: Severe asthma (SA) is one of the most challenging respiratory diseases to diagnose and manage. In addition, it is often considered a non-controlled entity despite, according to GINA guidelines, disease severity doesn?t necessarily relate to the degree of control. We, therefore, aimed to identify clinical, functional and inflammatory characteristics in well-controlled SA (i.e. GINA step 5).
 
Methods: Through a cross-sectional study we assessed a cohort of 130 SA. Asthma control was defined as: ACT score ?20, no acute asthma exacerbations in the previous year and FEV1% ?50%. Clinical (ACT, airway comorbidities), functional (FEV1%), biological (eosinophil count and exhaled fraction of Nitric Oxide - FeNO) and radiological features (chest CT) were recorded. Data series were tested for normality and expressed as mean SD or median and IQR, accordingly.
 
Results: Twenty-two patients (M:F=5:17) out of 130 (17%) resulted well-controlled according to criteria previously defined. Such sub-population showed a mean ACT of 22.23±1.38, no exacerbations and a mean FEV1% pred. of 77.23±11.69%. The median value of FeNO was 17-27.5 ppb and the median peripheral blood eosinophil count was 80-80 cell/?l. The overall prevalence of airway comorbidities was 36%. In detail, CRSwNP was present in 23% of SA, while 14% of patients had radiological evidence of bronchiectasis.  

Conclusions: Our results suggest that well-controlled SA are characterized by low T2 biomarkers and a lower rate of concomitant respiratory diseases, compared to what commonly reported in literature for SA (i.e. >50%). Obtained findings, if confirmed by larger studies, may support clinicians in identifying those subjects at lower risk to lose disease control.