Background: To compare health care utilization and cost by asthma severity and type of health insurance in Thailand.

Methods: A retrospective cohort study using an electronic database was conducted in patients with asthma. Patients who were diagnosed with asthma from 2009 to 2011, had at least two subsequent health care encounters for asthma during the first six months after the first asthma diagnosis, and had at least 90 days of follow-up were included. The primary outcome was direct health care costs of inpatient and outpatient care. We compared outcomes between groups on the basis of a proxy of severity (mild/moderate severe asthma vs. high severe asthma) and type of health insurance using a multivariable generalized linear model. Covariates such as Patients' demographic characteristics, comorbidities, and concurrent medications were included in the model.

Results: Among 1982 patients included, the average age was 40.3 ± 24.0 years, with 60.7% being males. A total of 1936 patients had mild/moderate severe asthma, whereas 46 patients had high severe asthma. There were 1293 patients under the Universal Coverage Scheme, 264 patients under Social Security Insurance, and 626 patients under the Civil Servant Medical Benefit Scheme (CSMBS). The average annual cost per patient was $598 ± $871. In adjusted analyses, the health care cost of patients with high severe asthma was $71 higher than that of patients with mild/moderate severe asthma (95% confidence interval $−131 to $274). The cost of patients under the CSMBS was $110 (95% confidence interval $29–$191) higher than that of patients under Universal Coverage Scheme.

Conclusions: Health care costs of patients with asthma were substantial and were higher in patients with high severe asthma and patients under the CSMBS.