Pulmonary Rehabilitation Reduces Airway Inflammation in Asthma Patients with High Fe_NO Levels

Pulmonary rehabilitation (PR) is a well-established non-pharmacological intervention for patients with asthma. While PR improves asthma control and exercise capacity, its impact on airway inflammation remains unclear. Fractional exhaled nitric oxide (Fe_NO) is a biomarker of type 2 airway inflammation, yet its response to PR has not been extensively studied. Therefore, aim of this study was to investigate diurnal variations in Fe_NO and how Fe_NO develops during PR in asthmatic patients with different levels of Fe_NO.

This prospective, single-center study investigated Fe_NO changes in asthma patients undergoing a comprehensive three-week inpatient PR program. The study observation period covered 15 consecutive days of FeNO measurements. Patients were divided into three subgroups according to their initial Fe_NO measurement: low (<25 ppb), intermediate (25-50 ppb) and high (>50 ppb). Fe_NO was measured three times a day, along with assessments of asthma control, lung function, blood eosinophils and exercise capacity before and after PR.

Sixty-two patients were included. Only patients in the high Fe_NO group (n=22) showed a significant 40% decrease in Fe_NO from pre to post PR (93±29 ppb to 56±27 ppb, p<0.001), independent of medication changes. Fe_NO levels of patients with low (17±8 ppb to 16±10 ppb) and intermediate levels (39±12 ppb to 30±10 ppb) remained unchanged. Asthma control and exercise capacity improved across all three subgroups, with the greatest gains observed in patients with initially high Fe_NO. No significant Fe_NO changes occurred in the low and intermediate Fe_NO groups.

PR significantly reduced Fe_NO levels in asthma patients with high baseline Fe_NO, suggesting an anti-inflammatory effect beyond pharmacological treatment. These findings highlight the role of PR as a complementary strategy in asthma management, particularly for patients with persistent airway inflammation despite optimized medication. Further randomized trials are needed to confirm these results and explore long-term effects.