BackgroundAlthough socioeconomic impact on asthma control has been investigated, little is known about its relationship to specialist referral of patients with possible severe asthma, especially in a public healthcare setting. The present study aims to identify socioeconomic patterns in disease control and referral of patients with asthma in a nationwide cohort of adult patients treated with inhaled corticosteroids (ICS).MethodsAsthma patients fulfilling the following criteria were included: aged 18–45 years and redeeming two or more prescriptions of ICS during 2014–2018 based on data from Danish national registers. Possible severe asthma was defined as Global Initiative for Asthma 2020 step 4 (with either two or more courses of systemic steroids or at least one hospitalisation) or step 5 treatment. Findings presented as odds ratios (95% confidence intervals).ResultsOut of 60 534 patients (median age 34 years, 55% female), 3275 (5.7%) were deemed as having possible severe asthma, of whom 61% were managed in primary care alone. Odds of specialist management for possible severe asthma decreased with age (OR 0.66, 95% CI 0.51–0.85; 36–45 versus 18–25 years), male sex (OR 0.75, 95% CI 0.64–0.87), residence outside the Capital Region (OR 0.70, 95% CI 0.59–0.82) and with receiving unemployment or disability benefits (OR 0.75, 95% CI 0.59–0.95). Completion of higher education increased odds of specialist referral (OR 1.28, 95% CI 1.03–1.59), when compared to patients with basic education.ConclusionEven in settings with nationally available free access to specialist care, the majority of patients with possible severe asthma are managed in primary care. Referral of at-risk asthma patients differs across socioeconomic parameters, calling for initiatives to identify and actively refer these patients.