Low-dose oral corticosteroids in asthma associates with increased morbidity and mortality

Long-term oral corticosteroid (OCS) treatment for severe asthma is known to cause significant adverse effects, but knowledge on effects of lower exposures in general asthma populations is limited. We aimed to explore this in a nationwide Danish asthma population.Users of asthma medication aged 18-45 years were identified in the Danish nationwide registers during 1999-2018 and followed prospectively in an open-cohort design. Incident OCS users were matched 1:4 to nonusers by propensity scores with replacement. Associations between OCS use and incident comorbidities were examined by Cox regression. Mortality rates, causes of death and rates of unscheduled hospital visits were assessed.OCS users (n=30 352) had, compared with nonusers (n=121 408), an increased risk of all outcomes with evident dose-response relationships starting at cumulative doses of ≤500 mg (prednisolone-equivalent). Hazard ratios ranged from 1.24 (95% CI 1.18-1.30) for fractures to 8.53 (95% CI 3.97-18.33) for adrenal insufficiency. Depression/anxiety had the highest incidence rate difference at 4.3 (95% CI 3.6-5.0) per 1000 person-years. Asthma-specific mortality rates were generally low at 0.15 (95% CI 0.11-0.20) and 0.04 (95% CI 0.02-0.06) per 1000 person-years for OCS users and nonusers, respectively. Mortality rates and unscheduled hospital visits increased with increasing OCS exposure.The study findings should be interpreted with their observational nature in mind. However, we found that even at low cumulative exposure, OCS use in asthma management was associated with increased risk of comorbidities, mortality and unscheduled hospital visits. Effective strategies for optimising asthma control and reducing OCS use are pivotal in asthma management.