The revenue proportion of leading public hospitals decreased from 63.42–60.16%, and that of private hospitals decreased from 37.90–34.93%. Concurrently, there was an observed increase in the proportion of member hospitals, aligning with patterns identified in previous research [48, 49]. It indicated that the MAs reform has effectively improved the capacity of grassroots service through sinking leading hospitals' resources, which further guaranteed the balanced distribution of high-quality resources and the fairness of services.
Public hospital maintained steady revenue proportions, whereas private hospitals displayed fluctuating and ascending proportions when both serving as leading institutions. From the results of ITSA, when both public and private hospitals were the leading hospitals, the revenue proportion of public hospital was not significantly affected. In contrast, the revenue proportion of private hospital experienced a decline during the reform period, followed by a subsequent rebound. Previous studies have shown the generally higher medical quality and service efficiency of public hospitals compared to private hospitals[45]. This inherent competitiveness allows public hospitals to sustain a stable revenue proportion. Private hospitals were at a disadvantage in the competition with other public hospitals, which resulted in their instantaneous decrease trend. Meanwhile, private hospitals that can be selected as MAs leading hospitals have strong service capabilities themselves. Furthermore, the leaders of leading private hospitals will also have stronger enthusiasm due to the leadership of MAs [47]. In addition, leading hospitals can provide higher income and better career development opportunities, so more medical service providers with higher education level would be attracted to the leading private hospital[48]. Therefore, the leading private hospitals have certain recovery capability, the proportion of hospital revenue in the later stage of reform has rebounded significantly.
Secondly, the revenue proportion of member hospitals with different ownerships showed a downward trend. When both public and private hospitals were member hospitals, the proportion of hospital revenue decreased. This phenomenon can be attributed to various factors. Firstly, when the leading hospital has a greater power to formulate performance appraisal standards and allocate surplus funds, it will drive it to extract patients from member hospitals through MAs to earn more medical funds[49, 50]. Additionally, the selection criteria employed by leading hospitals tend to favor institutions with robust medical service capabilities, featuring high-level medical professionals, advanced diagnostic and treatment technologies, and extensive resources such as large-scale equipment. In order to increase hospital revenue, the leading medical institutions may engage in overtreatment, which is a common problem in China [30, 51]. Moreover, even if the higher-level medical institutions have the willingness to refer patients downward, the constrained availability of resources such as equipment, beds, and drugs in member hospitals may limit the actualization of downward referrals[52]. Although the results of descriptive analysis indicated positive outcomes from the MAs reform, it was still necessary to strengthen the supervision of the leading hospitals, enhance the service capacity of member hospitals, in order to curb the trend of diverting patients from member hospitals.
In addition, the reasons for the change of revenue proportion in member hospitals with different ownership were different. Specifically, the proportion of outpatients in member public hospitals decreased, while the proportion of inpatients in member private hospitals decreased. Previous studies have also shown that the proportion of hospitalizations in public hospitals is generally higher than that of private hospitals, and most of them were complex cases or operations required to treat patients with multiple injuries[17–19].On the one hand, due to the different functional positioning of inpatient services and outpatient services, it is more difficult to treat the diseases that need to be hospitalized and the level of medical services varies greatly among different medical institutions. On the other hand, the level of hospitalization expenses in the private sector is higher than that in public hospitals[17].Therefore, residents generally choose public medical institutions with more advanced medical technology for hospitalization[53, 54], thereby contributing to the observed decline in inpatient proportions within member private hospitals. For outpatient services with relatively low technical complexity, residents will be more inclined to go to private hospitals when there is not much difference in the level of outpatient expenses between public and private hospitals. The superior patient experience often encountered in private healthcare facilities also influences this trend, thereby resulting in a reduction in the proportion of outpatient visits to public hospitals.
Finally, empowering private hospitals with leadership roles or reinforcing oversight mechanisms may constrain their unreasonable behavior. According to the results of the average length of stay, the level of public hospitals has remained relatively stable. The post-reform level (8.58 days) of leading public hospitals was lower than the average level of China in 2021 (9.2 days). Conversely, the average length of stay of member private hospital increased from 15.29 days to 16.16 days after the reform, and kept this increasing trend by 0.321 days per month(p < 0.01). The leading private hospital did not appear the unreasonable behavior. As member hospitals, the private hospitals need to face the strong competition from both leading hospital and public hospitals at the same time. When they were unable to increase their proportion of hospitalizations, in response, they may choose unconventional efforts and higher risk strategies, such as extending hospitalization time, to make up for losses in hospital revenue[55]. Therefore, to provide health care through private providers requires strong regulatory, management and information capabilities[56].
Limitations of the study
This study has several limitations. Firstly, in addition to the MAs reform, there may be other disruptive factors affecting the changes in the market share of public and private hospitals, such as medical technology and equipment, patient needs and preferences, geographical location and transportation accessibility, which may also have potential impacts. Secondly, our study utilized a 24-month period for the comparative analysis using ITSA, although this timeframe allowed us to examine market share changes, it may not capture longer-term trends or account for potential changes beyond the observed period. Future studies with longer observation periods could provide a more comprehensive understanding. Thirdly, the specific characteristics of the sample regions and hospitals may not be fully representative of the broader healthcare landscape. The applicability of our results to other regions or healthcare alliance systems should be interpreted with caution.