High Use of Antidepressant Medication in Both Mild-to-Modelate and Possible Severe Asthma - A Nationwide Cohort Study

Purpose: In asthma, increased severity has been linked to depression assessed as assessed by patient-reported outcomes. However, little is known about predictors of antidepressant use in asthma compared to the background population.

Methods: The study consists of 60,534 asthma patients aged 18-45 and a 1:1 age- and sex-matched control group. Using national registries and prescription data, the prevalence of and risk factors for antidepressant use were investigated by logistic regression adjusted for age, sex, workforce and civil status, income- and education-level and comorbidity. Results presented as odds ratio (OR) with 95% confidence intervals (CI).

Results: A total of 16% and 22%, respectively, among patients with mild-to-moderate and possible severe asthma redeemed antidepressant drugs, compared to 10% of controls. Antidepressant use was more prevalent amongst patients with high rescue medication use (>600 annual doses) and those with a history of moderate or severe exacerbation(s). Both mild-to-moderate and possible severe asthma were independent risk factors for antidepressant use (OR 1.40 (95% CI 1.35, 1.46) and OR 1.55 (95% CI 1.41, 1.70), respectively). Female sex, age, being divorced or never married, having only primary education or currently being under education, as well as being on welfare/transfer income increased odds of antidepressant use. Completing higher education and having high income were associated with lower odds.

Conclusion: In asthma, antidepressant use is significantly higher than in the background population. Even after adjusting for known risk factors, asthma remains a predictor of antidepressant use, signalling a psychologic burden related to living with asthma.