Factors associated with the development of severe asthma - a nationwide study (FINASTHMA).

Abstract

Background: Severe asthma presents a major challenge to healthcare and negatively affects the quality of life of the patients. Understanding on the factors predicting the development of severe asthma is limited.

Objective: This study aimed at characterizing patients with severe asthma and establishing risk factors for the development of severe asthma in a Finnish sample with a nationwide coverage of population, healthcare and drug register data.

Methods: We used data from January 1st, 2014 to December 31st, 2020. Pooled data over the years were used to identify characteristics of patients with severe asthma. Annual data were used in machine learning methods and logistic regression to identify factors predicting the development of severe asthma.

Results: Analysis of pooled data including 242,164 individuals showed that patients with severe asthma were more often women, slightly older, multimorbid and had higher body mass index values compared to patients with non-severe asthma. They also had higher use of non-asthma-related medications, manifesting as polypharmacy. Annual data from 6,908 patients showed that the most significant predictors of the development of severe asthma were being aged 51-60 (odds ratio (OR) 3.90 [95% confidence interval (CI): 3.42-4.47], chronic sinusitis (OR 2.48 [95% CI: 2.12-2.89]) and higher blood eosinophil counts (≥600 cells/μl, OR 2.10 [95% CI: 1.56-2.28]). Increases in all medications (non-asthma and asthma medications) were observed in the year before the onset of severe asthma.

Conclusion: The results provide a clinically relevant risk factor profile for early identification of the patients at risk of developing severe asthma.