Mortality in severe asthma: results from the NORDSTAR cohort

BACKGROUND: Longitudinal data addressing the impact of asthma severity on mortality are lacking. We aimed to explore all-cause and cause-specific mortality according to asthma severity. METHODS: The present registry-based cohort study is based on Danish data from the NORdic Dataset for aSThmA Research (NORDSTAR) research collaboration platform. Adult patients with severe asthma were matched on age and sex to 10 patients with mild-to-moderate asthma and followed from 2000 to 2020. Patients with COPD diagnosed prior to inclusion were excluded. Absolute and relative measures of all-cause and cause-specific mortality were compared between severe and mild-to-moderate asthma. RESULTS: 3.8% (95% CI 3.6-4.0%); p<0.001) also contributing. Although rare, the relative risk of asthma-related deaths was three-fold in severe asthma patients (HR 2.95, 95% CI 2.08-4.18; p<0.001). CONCLUSIONS: In this nationwide cohort, severe asthma was associated with a significantly higher mortality risk compared to mild-to-moderate asthma. The increased risk was primarily driven by respiratory-related deaths, with OCS use and T2 inflammation as contributing mortality risk factors.