The prevalence of severe asthma, use of oral corticosteroid and management strategies in the Nordic countries: results from the pan-Nordic NORDSTAR cohort

Abstract

<b>Background:</b> The Nordic countries share similar health care systems, but the prevalence and management of severe asthma have not previously been evaluated and compared between the countries. <b>AIM:</b> Using data from the NORdic Dataset for aSThmA Research (NORDSTAR) cohort we compare the prevalence of severe asthma, the use of oral corticosteroids (OCS) in severe asthma, and to which extent these patients are followed in specialist care in the Nordic countries. <b>Methods:</b> NORDSTAR is a population-based, observational dataset of asthma patients based on Nordic registries. Using a cross-sectional design, we identified adult patients with severe asthma according to the ERS/ATS definition in 2018. High cumulative OCS use was defined as dispensed fillings ≥5 mg/day. Patients managed in specialist care were those with an asthma-related outpatient contact (only available in Sweden and Finland). <b>Results:</b> We identified N=6,477, N=6,999, and N=8,476 severe asthma patients corresponding to 3.5%, 5.4% and 5.2% of all asthma patients aged ≥18 in Sweden, Norway, and Finland, respectively. Most patients with severe asthma had a high cumulative use of OCS; 53%, 66% and 63% in the three countries, respectively. In Sweden and Finland, 33% and 39% of patients with high cumulative OCS use were currently managed in specialist care. <b>Conclusion:</b> Population-based nationwide data demonstrate a comparable prevalence of severe asthma and a high cumulative OCS use in the Nordic countries. Most patients with severe asthma and high cumulative OCS use are currently not managed by a respiratory specialist, indicating the need for increased awareness of severe asthma in primary care