Trends in asthma hospitalizations among adults in Spain: Analysis of hospital discharge data from 2011 to 2020

Aims: To analyze trends in asthma hospitalizations in patients over 15 years of age in Spain. To identify possible changes in incidence, demographic characteristics, clinical conditions, and outcomes. Methods: We conducted an observational retrospective epidemiological study using the Spanish National Hospital Discharge Database and included all patients hospitalized with a diagnosis of asthma from 2011 to 2020. Results: A total of 1,102,923 patients were hospitalized with a code for asthma in any diagnostic position; of these, 153,749 (13.94%) had asthma coded as the primary diagnosis (asthma exacerbation). The number of patients with an asthma exacerbation decreased over time, from 15,356 in 2011 to 8804 in 2020. In-hospital mortality (IHM) remained low (around 1.5%) and stable in this subgroup of patients. When the diagnosis of asthma appeared in any diagnostic position, hospitalizations increased for all ages and sexes. In this case, a significant change was observed for IHM, which increased from 3.27% in 2011-12 to 4.36% in 2019-20 (p < 0.001). The main risk factors for IHM in both cases were age over 65 years, need for mechanical ventilation, and associated diagnoses of pneumonia, heart disease, or atrial fibrillation. In contrast, obesity was a predictor of lower mortality. Conclusion: Our results suggest a decline in the incidence of hospitalizations for asthma exacerbations from 2011 to 2020. In contrast, the number of patients with asthma in any diagnostic position increased progressively, as did mortality, probably owing to an increase in comorbidities in a gradually ageing population.