Comorbidity Burden in Severe and Nonsevere Asthma: A Nationwide Observational Study (FINASTHMA)

Background: Asthma, affecting more than 330 million people worldwide, is associated with a high level of morbidity, mortality, and socioeconomic costs. Objective: In this cross-sectional study, we analyzed the comorbidity burden in patients with severe asthma compared with nonsevere asthma and investigated the role of corticosteroid use on the risk of comorbidities. Methods: All adults (≥18 y) with a diagnosis of asthma (International Classification of Diseases–10th revision code J45.x) between 2014 and 2017 were identified and data were collected until 2018 from Finnish nationwide registers. Asthma was defined as continuously or transiently severe or nonsevere based on annual dispensed inhaled corticosteroids (ICS), oral corticosteroids (OCS), and hospitalizations. Results: Of 193,730 adult identified patients diagnosed with asthma, 86.3% had nonsevere, 8.1% transiently severe, and 5.6% continuously severe asthma. Excess prevalence of pneumonia was observed in continuously (22%) and transiently severe (14%) compared with nonsevere patients after adjusting for age and sex. Cataract, osteoporosis, obesity, heart failure, and atrial fibrillation were also more frequent in severe asthma patients. The ICS and/or OCS use contributed to the risk of several comorbidities in a dose-dependent manner, particularly pneumonia, osteoporosis, obesity, heart failure, and atrial fibrillation. High OCS use and the presence of comorbidities were associated with increased health care resource use. Conclusions: Patients with severe asthma have a high burden of comorbidities, especially pneumonia. Many of the comorbidities have a strong dose-dependent association with ICS and OCS treatment, suggesting that corticosteroid doses should be carefully evaluated in clinical practice.