Tobacco Exposure and Efficacy of Biologic Therapy in Patients With Severe Asthma: A Nationwide Study From the Danish Severe Asthma Register

Background: Randomized trials of biologics in severe, uncontrolled asthma have excluded patients with a cumulative tobacco exposure of more than 10 pack-years. Therefore, our knowledge of the impact of smoking exposure on the clinical effects of biologics in severe asthma remains incomplete. However, because many patients with asthma are current or former smokers, investigating the potential impacts of tobacco exposure on the effects of biologic treatment is clinically important.

Objective: To investigate the impact of smoking history and tobacco exposure on the effectiveness of biologic therapy in real-life patients with severe asthma.

Methods: We used data from a complete nationwide cohort of patients with severe asthma who were receiving biologics, the Danish Severe Asthma Register. We divided patients according to smoking history and cumulative tobacco exposure and analyzed data at baseline and after 12 months of biologic treatment.

Results: A total of 724 bio-naive patients were identified in the Danish Severe Asthma Register, 398 of whom had never been smokers (55%), 316 were previous smokers (44%), and 10 were current smokers (1%). Within the group of current and former smokers, 37% had 1 to 9 pack-years of tobacco exposure, 26% had 10 to 19 pack-years, and 37% had 20 or more pack-years of tobacco exposure. Patients with tobacco exposure had similar reductions in the number of exacerbations, reductions in maintenance oral corticosteroid use, and improvements in asthma symptoms compared with patients with 0 pack-years.

Conclusion: Former smoking history and lifetime tobacco exposure do not have an impact on the efficacy of biologics in patients with severe asthma.