Materials and methods
2.1 data source
This study employed a natural experiment design with a nationwide, populations-based dataset to examine the impacts of the Taiwan version of the DRG payment scheme. In 2009, 486 hospitals were contracted with the BNHI, accounting for more than 95% of all hospitals in Taiwan, and more than 99% of Taiwan residents were enrolled in the compulsory health insurance program. The analysis presented in this study is based on the nationwide NHI claims dataset from 2009 to 2010 in Taiwan.
2.2 DRG payment
Beginning with its inauguration on March 1, 1995, the BNHI implemented a case-payment scheme, which was a simplified version of a prospective payment system similar to the DRG in the United States. The case-payment scheme reimbursed a predetermined, fixed amount for each patient admitted into a hospital for certain surgical procedures, such as appendectomy or Caesarean section. However, this scheme did not adjust for age, sex, or discharge status. Patients underwent those procedures would be reimbursed by a fixed amount of reimbursement; however, a certain proportion of patients with complication/co morbidity or consumed higher resources during a hospital stay could be reimbursed by fee-for-services schemes via application. The total number of surgical procedures under the case-payment scheme increased between 1995 and 2009 from 3 to 54
The BNHI developed the Taiwan version of DRG payments scheme based on the 18th version of DRG provided by center for medicare and Medicaid services (former health care financing administration). It reimburses a fixed rate per admission while accounting for age and sex, discharge status, and the presence of complications or co morbidities. Currently, the Taiwan version of DRG consists of 1029 codes and excludes several categories, such as psychiatric disorders, cancer treatments etc. The DRG payment scheme was introduced gradually by various groups beginning in 2010 and is scheduled to be completed in 2014. In order to minimize the impact of DRG payment, in 2010 the BNHI started with the 164 categories of DRGs which were derived and sub-categorized from the original 54 categories in the case-payment scheme. Inpatient services that will adopt the DRG payment in the second year (2011) or later were reimbursed by fee-for-services schemes in 2010 as usual.