The burden of adult asthma in Finland: impact of disease severity and eosinophil count on health care resource utilization

Medaffcon’s new real-world evidence study on the burden of adult asthma in Finland demonstrates the impact of disease severity and eosinophil count on health care resource utilization.

Asthma is a heterogenous disease characterized by chronic airway inflammation and respiratory symptoms, and it is thought to affect approximately 235 million people worldwide. The prevalence in the adult population in Finland is estimated to be around 10 %. Severe asthma is a form of the disease that requires treatment with high-dose inhaled corticosteroids (ICS) and a second controller, and/or systematic corticosteroids for more than 50 % of the year to maintain control, or asthma that remains uncontrolled despite these treatments. One form of severe asthma is severe eosinophilic asthma, defined as severe asthma with a blood eosinophil count of ≥ 300 cells/µl. Although only 5-10 % of asthma patients have severe asthma, it places a high burden on health care systems. The aims of this retrospective registry study were to describe the health care resource utilization (HRCU) and associated costs in patients with asthma according to disease severity and blood eosinophil levels, and to the determine mortality and the burden of comorbidities in these patient groups.

This study, done in collaboration with the Turku University Hospital and GSK, utilized real-world evidence (RWE) data from the hospital register of the Hospital District of Southwest Finland. All adult patients who were treated for asthma between 2004 and 2015 were included in the study. Patients were categorized according to asthma severity and blood eosinophil count (under or over 300 cells/µl), and patients that presented with severe asthma during the study period were classified as having transitioning asthma. The total HRCU in the first year after diagnosis and following calendar years was calculated from hospital inpatient days and visits, outpatient visits, emergency room (ER) visits, hospital laboratory tests and procedures, and compared between the different patient groups. Comorbidities were assessed at the end of the study period based on ICD-10 codes, and asthma related mortality (with asthma being the direct, indirect or contributing cause of death) figures were obtained from Statistics Finland.

Of the 14,398 patients included in the analysis, only 2.7 % had severe asthma at the beginning of the study and another 5.9 % presented with severe asthma during the study period. Blood eosinophil counts were available for 26.3 % of the patients, and the majority (62.1 %) had normal eosinophil counts of under 300 cells/µl. A total of 270 patients (1.9 %) had severe eosinophilic asthma, i.e. severe asthma with a blood eosinophil count ≥ 300 cells/µl at any time during the study period. Patients with severe asthma had a higher rate of HCRU, and the total and asthma-related costs were higher compared to those with non-severe asthma. The highest cost per patient year (€ 5143) was observed for those with severe eosinophilic asthma (vs. € 1878 for those with non-severe asthma). The comorbidities between the patient groups were also compared, and essential hypertension, pneumonia, sleep disorders, type 2 diabetes, atrial fibrillation and flutter, and age-related cataract were more common in patients with severe asthma compared to patients with non-severe asthma. Finally, asthma-related deaths occurred in less than 5 % of the patients in all of the patient groups during the study period, but overall survival was reduced in patients with severe asthma.

The results from this RWE study clearly demonstrate the high burden associated with asthma in Finland. The burden is especially high for the small group of patients with severe eosinophilic asthma, possibly due to the high comorbidity burden for these patients. Even though the implementation of the national Finnish asthma and allergy programs has been shown to be associated with a marked reduction in hospitalizations and lost productivity, our findings indicate that there is still work to be done, and new treatment strategies are needed for the patients with severe and/or eosinophilic asthma who are currently not achieving adequate control.