The Combined Impact of Exhaled Nitric Oxide and Sputum Eosinophils Monitoring in Asthma Treatment: A Prospective Cohort Study.

BACKGROUND

Inhaled corticosteroids (ICS) treatment for asthma control is generally focused on lung function and symptoms, but inadequately correlated with airway inflammation.

OBJECTIVE

To compare asthma control in a group of patients whose treatment was based on fraction of exhaled nitric oxide (FENO) and sputum eosinophils (intervention group) with a group in whom treatment was based on clinical score (control group). Study design and primary outcome: Randomized parallel-group longitudinal 24-month study including 5 visits every 6 months. A combination of asthma exacerbation rate and symptom score at 24 months was the primary outcome.

PARTICIPANTS

Fourteen patients with eosinophilic asthma per group were included.

RESULTS

In the intervention group, exacerbation rate/patient/year was reduced at 12 months (0.82) (-73%) and, to a greater extent at 24 months (0.5) (-84%) compared with baseline (3.21, p<0.01). In the control group, a significant reduction in exacerbation rate/patient/year was only observed between month 12 (3.0) and 24 (2.0, -33%, p<0.01). At 24 months, exacerbation rate was lower (-75%) in the intervention (0.5) than in the control group (2.0, p<0.05). Compared with baseline, mean symptom scores at 24 months were reduced in both groups (intervention group: -72%; control group: - 60%), but were lower in the intervention (8.1±1.0, p<0.05; -27%) than in the control group (11±2.6). ICS dose gradually increased in both groups throughout the study, with no between-group differences.

CONCLUSION

Compared with conventional strategy, longitudinal monitoring of FENO and sputum eosinophils improves eosinophilic asthma control in terms of reduced symptoms and exacerbations without additional increase e in ICS treatment.