Background

Little is known about how smoking affects asthma patients? characteristics, and therefore may impact treatment choices regarding biologic therapy (BT) and its therapy response

Objective

Our aim was to evaluate the impact of smoking on baseline data in patients with severe asthma.

Methods

We analysed patients? characteristics including pulmonary function tests, asthma control, exacerbation rate and biomarkers. We performed linear models comparing smokers vs. never-smokers, and three pre-defined groups stratified by smoking history (<10 pack-years (py), 10-20 py, >20 py). Data was obtained from GAN.

Results

We included 2.478 patients: 65 (2.6%) active smokers, 1.005 (40.6%) ex-smokers and 1.408 (56.8%) never-smokers. 529 patients (21.3%) had <10 py, 304 (12.3%) 10-20 py and 237 (9.6%) >20 py. Smoking was associated with worse asthma control (>20 py: ACT -1.77 points (p <.001); mini-AQLQ -4.88 (p=.004)), while exacerbation rate and oral corticosteroid doses were similar. Smoking was associated with worse lung function indicating smoking-related lung injury e.g. DLCO (0.85-fold lower with 10-20 py (p<.001) resp. 0.82 fold lower with >20 py (p<.001)). Smokers had greater signs of hyperinflation (higher RV (p<.001) and TLC (p<.008)). Regarding biomarkers smoking was associated with 1.58-fold higher IgE levels (>20 py: p=.002), 0.84-fold lower FeNO concentrations (p=.001) and 2.12-fold higher blood eosinophil count (BEC, p=.045).

Conclusion

Smoking history in patients with severe asthma significantly affects baseline characteristics, such as IgE levels, FeNO, BEC and pulmonary functionthereby impacting treatment choices regarding BT and possibly response to therapy.