It is widely recognized that DRG is one of the most advanced and scientific payment methods in the world. Under the implementation of DRG payment, hospitals can keep any savings but also bear any cost overruns (8). That is, the source of profit under FFS payment, such as drugs and medical materials, can become the source of costs under the DRG system (10). Therefore, financial risk is further transferred to the provider. In particular, when the hospitalization expenditures exceed the DRG payment rates, the provider has more initiative to reduce the overrun cost (7). Induced demand will be suppressed, which will help doctors implement standard treatment regimens in accordance with authoritative clinical guidelines. By analysing the trend of variation in hospitalization expenditures for patients with similar medical conditions, we can analyse whether DRG payment can contribute to the consistency of health services.
The study found that when there were no significant differences in age, gender, disease severity, or disease type, the variation of hospitalization expenditures and its changing trend with time were still different among patients with different payment methods. Compared with the patients under FFS payment, patients under DRG payment had less variation in hospitalization expenditures. The variation in most years showed a downward trend, and the decrease was larger in the intervention group than that in the control group. The median of hospitalization expenditures for the intervention group was lower than the payment rate, and the opposite was observed in the control group. This indicates that the policy has played a certain role in reducing hospitalization expenditures and their variation. In patients with the three disease types, the use of clinical resources was more consistent after DRG payment. Since key clinical decisions are made by doctors, it can be assumed that the reduction in the variation in hospitalization expenditures presented in the study is due to more consistent treatment behaviours by doctors. This supports the premise that DRG payment helps suppress the induced-demand of FFS payment and promotes a more standard treatment plan that is closer to clinical guidelines.
The study also found that patients with AMI had the least reduction in the variation of hospitalization expenditures before and after DRG payment. This may be explained as that the treatment regimen of AMI has been very mature before the implementation of the policy, and universal consensus with clinical guidelines has already been established, so doctors’ behaviours have been regulated by a certain degree. Therefore, the effect of DRG payment on the variation in AMI hospitalization expenditures is not as obvious as that of other diseases. In addition, according to the analysis of hospitalization expenditures’ composition, most expenditures in the internal medicine group belong to drug expenditures, while medical materials are the greatest source of expenditures in the surgical group. It can be inferred that in the management of DRG payment, the internal medicine group and the surgical group can make medical services more consistent by regulating the use of drugs and medical materials, respectively.
Previous studies have shown that compared with FFS, DRG payment has achieved shorter hospital stays (8), slower medical cost growth (11), better care processes (9), more efficient management (12, 13) and a more reasonable cost structure. Past experience shows that the variation in hospitalization expenditures will decrease after DRG payment implementation (6)which is largely consistent with the results of this study. Based on this effect, we tried to explore the main factors behind the decrease. The causes of variation in DRG internal resource utilization are complex. Obviously, one potential explanatory variable is the severity of the disease, but this is not the only variable or the most important one. The study showed that the average cost of the same procedure varied among surgeons (14), and the differences between doctors are even greater than those between hospitals (15). Therefore, doctors must be a primary control variable (16) in interpreting DRG internal resource changes. Studies have shown that changes in doctors’ practice can reduce the variation in hospitalization expenditures more than the severity of illness (16). The decrease in hospitalization days was due more to changes in doctors’ behaviour than to a decrease in disease severity (5, 6). This provides further support for the results of this study. After controlling for individual difference, the reduction in the variation in hospitalization expenditures is more likely due to a more consistent clinical practice among doctors.
1. In this study, the impacts of doctors’ behaviour on the reduction of variation in hospitalization expenditures were examined by controlling the individual differences of patients. However, the reduction in the variation of hospitalization expenditures is not the same as the regulation of doctors’ practices. In the future, detailed measurement of doctors’ practices should be conducted based on information such as specific treatment programs.
2. Although the results show a reduction in the variation of hospitalization expenditures, the consistency of hospitalization expenditures is not always equivalent to the standardization of health services. It remains to be analysed whether the clinical resources of patients are used in the most rational way and whether there is a risk of inadequate services affecting the quality of care. Future research should focus on which types of expenditures are most effective in improving quality and which types of expenditures represent waste. A complete list of necessary treatments should be established. The balance between reasonable cost control and reasonable diagnosis and treatment under DRG should be analysed.