West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China.
Institute for Healthy Cities and West China Research Center for Rural Health Development, Sichuan University, Chengdu, China.
Front Public Health. 2021 Aug 18;9:721504. doi: 10.3389/fpubh.2021.721504. eCollection 2021.
This study aims to provide empirical evidence for the controversy about whether the inference is consistent if alternative hospital market definition methods are employed, and for which definition method is the best alternative to the predicted patient flow approach. Collecting data from the discharge data of inpatients and hospital administrative data of Sichuan province in China in the fourth quarter of 2018. We employed Herfindahl-Hirschman Index (HHI) as the proxy of market competition used as an example to measure the hospital market structure. Correlation coefficients of HHIs based on different definition methods were assessed. The corresponding coefficient of each HHI estimated in identical regression models was then compared. In addition, since the predicted patient flow method has been argued by the literature of its advantages compared with the previous approaches, we took the predicted patient flow as a reference to compare with the other approaches. We selected the common diseases with a significant burden, and 11 diseases were included (902,767 hospitalizations). The correlation coefficients of HHIs based on different market definition methods are all significantly greater than 0, and the coefficients of HHIs are different in identical regression models. Taking the predicted patient flow approach as a reference, we found that the correlation coefficients between HHIs based on fixed radius and predicted patient flow approach is larger than others, and their parameter estimates are all consistent. Although the HHIs based on different definition methods are significantly and positively correlated, the inferences about the effectiveness of market structure would be inconsistent when alternative market definition methods are employed. The fixed radius would be the best alternative when researchers want to use the predicted patient flow method to define the hospital market but are hindered by the data limitations and computational complexity.
本研究旨在为关于采用替代医院市场定义方法时推断是否一致的争议提供经验证据，以及哪种定义方法是预测患者流量方法的最佳替代方法。从 2018 年第四季度中国四川省住院患者出院数据和医院管理数据中收集数据。我们使用赫芬达尔-赫希曼指数（HHI）作为市场竞争的代理，作为衡量医院市场结构的示例。评估了基于不同定义方法的 HHI 的相关系数。然后比较了在相同回归模型中估计的每个 HHI 的相应系数。此外，由于预测患者流量方法在文献中被认为具有优于先前方法的优势，我们将预测患者流量作为参考与其他方法进行比较。我们选择了负担显著的常见疾病，包括 11 种疾病（902,767 例住院）。基于不同市场定义方法的 HHI 的相关系数均显著大于 0，并且在相同回归模型中 HHI 的系数不同。以预测患者流量方法为参考，我们发现基于固定半径的 HHI 与预测患者流量方法之间的相关系数大于其他方法，并且它们的参数估计值均一致。尽管基于不同定义方法的 HHI 显著正相关，但当研究人员希望使用预测患者流量方法来定义医院市场但受到数据限制和计算复杂性的阻碍时，替代市场定义方法的推断将不一致。当研究人员希望使用预测患者流量方法来定义医院市场但受到数据限制和计算复杂性的阻碍时，固定半径将是替代方法的最佳选择。
