Evaluating performance of local case-mix system by international comparison: a case study in Beijing, China

Case-mix is an important tool for health planning and management in many countries. As a major developing country, China is considering the introduction of the case-mix system in the health reform. Beijing, the capital of China, developed a local case-mix version whose performance needs to be evaluated before utilization.

The objective of this study was to evaluate the performance of the case-mix system developed in Beijing by comparing it with those used in Australia and the U.S.A.

A total of 1.3 million inpatient records from 154 hospitals in Beijing in 2008 were grouped respectively using three case-mix systems: (i) Beijing Diagnosis Related Groups (BJ-DRGs); (ii) US-based All Patient DRGs; and (iii) Australian Refined DRGs. Coefficient of variation (CV) and reduction in variance (RIV) were used to measure the performance of DRGs system.

The BJ-DRGs produced the best CV and RIV results for expenditure. However, at the level of Major Diagnostic Category (MDC), three MDCs of BJ-DRGs gave the poorest RIVs for both expenditure and length of stay.

Although the performance of BJ-DRGs was acceptable, further revision and improvement is needed. Comparisons with other mature DRGs versions can assist in identifying the improvement priorities of the local version.