Health Care Utilization and Direct Costs in Mild, Moderate, and Severe Adult Asthma: A Descriptive Study Using the 2014 South Korean Health Insurance Database.

PURPOSE: Although asthma exacerbation comprises a large burden of the total asthma-related costs, few studies have examined the frequency and cost of acute exacerbation according to asthma severity. This study investigated asthma-related health care utilization and costs according to the severity of asthma.
METHODS: We conducted a descriptive study using the national health insurance claims database between January 1 and December 31, 2014. We included adult patients with asthma (18 years of age and older) who had ≥2 claims with for an asthma diagnosis and were prescribed ≥1 asthma medications. They were classified into 3 asthma severity levels (level 1 = mild, level 2 = moderate, and level 3 = severe), based on individual medication prescriptions. Acute exacerbation was defined as having a corticosteroid burst, an emergency department visit, or hospitalization. Health care utilization, acute exacerbation, and direct costs associated with asthma were compared according to asthma severity levels.
FINDINGS: Of the 36,687 adult asthma patients, level 1 had the largest proportion of patients (81.2%), followed by level 2 (18.2%), and level 3 (0.6%). The average number of asthma-related outpatient visits was 4.5 for level 1, 7.2 for level 2, and 11.9 for level 3 (P < 0.01). The estimated asthma-related direct cost per patient was $174 for level 1, $634 for level 2, and $1635 for level 3 (P < 0.01). The number of patients who experienced acute exacerbation increased as asthma severity increased: level 1, 22.6%; level 2, 26.0%; and level 3, 48.7% (P < 0.01). Direct costs associated with asthma exacerbation dramatically increased and accounted for 15.1% of the total cost in level 1 patients, 19.5% in level 2 patients, and 40.8% in level 3 patients (P < 0.01). IMPLICATIONS: The direct costs of acute exacerbation increased as asthma severity increased. In patients with severe asthma, acute exacerbation and the relative cost ratio in South Korea were higher than those in other countries. Proper management is required to avoid acute exacerbations and to reduce the burden of asthma, particularly in patients with severe asthma.