Background: Asthma-related mortality is low, and as a result, there is a paucity of data on clinical factors related to this endpoint.

Methods: In this retrospective, population-based study, we reviewed provincial health records of all patients whose primary cause of death was asthma between January 1, 2009, and December 31, 2019. We aimed to identify clinical features, which were associated with asthma-related mortality.

Results: We obtained data on 212 patients who presented to acute care with a diagnosis of an asthma exacerbation (mean ± SD age: 63±23 years, 43% female) who died and compared them to 304 matched patients who survived. In single and multi-factor modified Poisson regression models, we identified that a higher risk of asthma-related mortality was associated with the use of daily OCS (1.47; 1.05-2.08), any hospitalization in the 30 days prior to death (1.26; 1.04-1.53), living >50 km away from tertiary care (1.41; 1.14-1.76) and higher use of SABA in the year prior (1.06; 1.04-1.09).  However, both all-cause and asthma-specific ED visits were associated with a lower risk of asthma-related mortality.

Conclusion: Although the mortality rate due to asthma is quite low, there are certain clinical factors that are associated with higher asthma-related mortality. Identification of this patient population could help further reduce mortality due to asthma.