Active Smoking Reduces Long-Term Benefits of subcutaneous immunotherapy in Allergic Rhinitis Patients, Study Finds

The analysis revealed that in allergic rhinitis patients, while baseline severity was comparable among never, former, and current smokers, active smokers experienced diminished benefits from subcutaneous immunotherapy. Current smokers reported reduced early effectiveness and a decline in long-term benefits, particularly two years after starting treatment. Additionally, smoking was associated with a higher risk of asthma and more severe allergic conjunctivitis.

Zhihai Xie, Xiangya Hospital of Central South University, Changsha, People's Republic of China, and colleagues aimed to evaluate the impact of smoking statuses on disease severity and subcutaneous immunotherapy efficacy in allergic rhinitis (AR).

For this purpose, the researchers conducted an open observational cohort study at a tertiary referral center to evaluate the impact of smoking on allergic rhinitis patients undergoing SCIT for dust mite allergens. The study included 505 AR patients, who were classified into three groups: never-smokers, former smokers, and current smokers. Disease severity was assessed using standard questionnaires commonly used in clinical settings.

The study analyzed changes in questionnaire scores before and after SCIT to determine the efficacy of the treatment. By comparing these scores across the different smoking status groups, researchers aimed to identify differences in disease severity and the effectiveness of SCIT. This approach provided insights into how smoking influences both the severity of allergic rhinitis and the response to SCIT.

The following were the key findings of the study:

• Compared to never-smokers, former and current smokers exhibited a higher proportion of male, alcohol, and asthma.
• Current smokers had a greater prevalence of allergic conjunctivitis than former smokers.
• Before SCIT, AR severity was similar across three groups, even after adjusting for confounders.
• Current smokers reported lower SCIT efficacy in the first year.
• By the third year, three groups showed comparable long-term efficacy.
• Current smokers experienced a significant decrease in benefits two years post-SCIT and lower improvement rates at the end of the 3-year SCIT period and two years following SCIT.

The findings showed that patients with allergic rhinitis, regardless of smoking status, exhibited similar baseline disease severity and long-term efficacy from SCIT. However, active smoking was linked to a higher risk of asthma, a delayed perception of early SCIT benefits, reduced improvement over three years, and diminished advantages two years post-treatment.

"Prompt smoking cessation is essential to counteract these adverse effects and enhance treatment outcomes," the researchers concluded.

Reference: https://doi.org/10.1002/ohn.937