Universal coverage with supply-side reform: The impact on medical expenditure risk and utilization in Thailand

We estimate the impact on out-of-pocket (OOP) medical expenditure of a major reform in Thailand that greatly extended health insurance coverage to achieve universality while implementing supply-side measures intended to deliver cost-effective care from an increased, but modest, public health budget. Difference-in-differences comparison of groups to whom coverage was extended or deepened with those whose coverage did not change indicates that the reform reduced OOP expenditure by 28% on average and by 42% at the 95th percentile of the conditional distribution. Simulations suggest that exposure to medical expenditure risk was reduced by three-fifths, on average, generating a social welfare gain equivalent to 80-200% of the approximate deadweight loss from financing the reform. Estimated effects on health care access suggest that the policy managed to reduce households' medical expenses while also raising their utilization of both inpatient and ambulatory care.