Smoking and Lung Function Response to Inhaled Glucocorticoids in Adult-Onset Asthma.

INTRODUCTION

Tobacco smoking has been associated with reduced response to inhaled corticosteroids (ICS). However, little is known about how smoking affects lung function response to ICS treatment in new-onset asthma.

AIMS AND

OBJECTIVES

To evaluate the sub-acute ICS response on lung function in new adult-onset asthma in steroid-naïve patients classified according to smoking status in a real-life longitudinal cohort.

METHODS

In the Seinäjoki Adult Asthma Study, 203 patients with new adult-onset asthma were followed for 12 years. Patients who were dispensed ICS during the first two years of the follow-up were included (n=174). Lung function was evaluated at baseline, and the maximum lung function point was determined during the first 2.5 years (Max0-2.5). Patients were divided into groups by smoking status (never/ex/current smokers) and smoking history (never vs ever or <10 vs ≥10 smoked pack-years).

RESULTS

At asthma diagnosis 50% (n=90) were ex- or current smokers. The increase of forced vital capacity % predicted from baseline to Max0-2.5 was higher (p=0.025) in current smokers compared to never- and ex-smokers. No differences in lung function change between never vs ever smokers or in patients with <10 vs ≥10 pack-years smoked were found after ICS initiation, even after adjusting for individual ICS dose.

CONCLUSION

Although the harmful effects of smoking on asthma control and long-term lung function decline have been well established, sub-acute lung function response to ICS in adult-onset asthma seems not to differ according to smoking status. The result suggests that patients should have similar ICS therapy initiation regardless of their smoking history.

CLINICAL TRIAL REGISTRATION: This study is registered at www.ClinicalTrials.gov with identifier number NCT02733016.