There is scarce information on predictors of exacerbations (AE) in severe pediatric asthma (SA).

Objective: To evaluate in SA children, the association of clinical scores (CS), FeNO and spirometry (S)-impulse oscillometry (IO) with AE.

Methods: Prospective, longitudinal study. All patients with SA (GINA guidelines) aged 6-18 years old, followed at SA clinic were included (n 48). At enrollment, asthma control test (ACT ?19 uncontrolled), GINAq (controlled vs. uncontrolled/partially controlled), FeNO (cut off ?25ppb) and S/IO were performed. Number and severity of AE were evaluated at 3 and 6 months of follow-up. Measurements were taken in two consecutive semesters to avoid seasonality.

Results: Mean age 12.1 years (SD 3.2), male 42% (n 20). At first visit: ACT ?19, 21% (n 10), GINAq uncontrolled 46% (n 22), FeNO ?25ppb 56% (n 27). S: FVC% (mean/SD) 109±14, VEF1% 101±16, VEF1/FVC 82±10, FMMF% 87±40, BDR n 9 (19%); IO: Z5Hz% 91±23, R5Hz% 91±23, R10Hz% 90±20, X5Hz% 107±42, BDR n 2 (4%). 

More patients with asthma uncontrolled (GINAq) have shown AE vs. controlled ones:  67% (n 12) vs. 33% (n 6) (p 0.02) at 3 months and  63% (n 17) vs. 37% (n 10) (p 0.005) at 6 months. There were more AE/patient in uncontrolled patients (GINAq) vs. controlled ones: 1 vs 0.31 (p 0.04) at 3 months and 2.27 vs 0.57 (p 0.005) at 6 months.

Uncontrolled asthma patients (ACT) have evidenced more hospitalizations (H) than controlled ones at 3 and 6 months: 1 vs. 0 (p 0.04) and 3 vs. 2 (p 0.01), respectively. 

Neither FeNO nor lung function (S/IO) were associated with AE/H during follow-up.

Conclusion: In SA children, only the initial CS were associated with AE (GINAq) and H (ACT) at 3 and 6 months of follow-up.