Impact of Volume and Temporal Distance on the Value of Organ Transplant Surgery

描述(由申请者提供)：在包括器官移植在内的外科手术中，供者数量和患者结果之间的关系得到了充分的研究。器官移植的证据是有限的，而且在很大程度上是相关的。获取移植中体积对结果的可信的因果影响对于管理和政策决策是重要的。此外，手术中的时间距离被定义为提供者执行特定手术之间的时间，已被证明与较差的患者结果呈正相关。具体地说，当提供者最后一次执行手术的时间增加时，患者的情况会变得更糟。这种影响在移植中还没有被研究过。我们将使用2009-2011年移植受者科学登记处的数据，检查肾、肝和胰腺移植，以解决多个目标。首先，我们将使用计量经济学方法检验中心体积和时间距离对患者结果的相对影响，无论是在时间上的近端还是在较长的时间范围内，这些方法旨在产生这些影响的可信的因果估计，而不仅仅是统计关联。我们将使用中心固定效应回归建模技术来检验音量和时间距离效应。然后，我们建议使用现有的半参数危险建模技术，这些技术允许通过数值积分技术来解释未观察到的异质性。其次，我们将检验量或时间距离是否会影响资源使用。器官是一种稀缺资源，因此移植手术的质量影响着移植市场的效率。这种对质量和资源使用情况的检查将为评估这些中心为患者提供的价值提供一个框架。此外，一旦确定了体积和时间距离效应的大小，该信息可以直接用于向移植中心认证政策和干预措施提供信息，以维持移植中心的组织人力资本。 公共卫生相关性：拟议的研究对公共卫生具有重要影响，因为它涉及与器官移植手术护理的质量、安全和效率有关的问题。这项研究的结果将强调需要设计干预措施并制定政策，以保持移植中心的组织人力资本，改善移植程序的质量和价值。

DESCRIPTION (provided by applicant): There is a well investigated association between provider volume and patient outcomes in surgery, including organ transplantation. The evidence in organ transplantation is limited and largely correlative. Obtaining plausibly causal impacts of volume on outcomes in transplantation is important for managerial and policy decision making. In addition, temporal distance in surgery, which is defined as the time between a provider's performances of a particular procedure, has been shown to be positively related to poorer patient outcomes. Specifically, patients do worse when the time since their provider last performed the procedure increases. This effect has not been investigated in transplantation. We will examine the kidney, liver and pancreas transplants to address multiple aims, employing data from the Scientific Registry of Transplant Recipients for the years 2009-2011. First, we will examine the relative impact of center volume and temporal distance on patient outcomes both proximal to the procedure in time and over the longer horizon using econometric methods designed to yield plausibly causal estimates of these effects rather than only statistical associations. We will employ center fixed effects regression modeling techniques to examine volume and temporal distance effects. We then propose to use existing semi-parametric hazard modeling techniques that allow the unobserved heterogeneity to be accounted for through numerical integration techniques. Second, we will examine whether volume or temporal distance impacts resource use. Organs are a scarce resource, and as such the quality of the transplant surgery impacts the efficiency of the transplant market. Together this examination of quality and resource use will provide a framework for assessing the value the centers provide for patients. Furthermore, once the magnitudes of the volume and temporal distance effects are identified, this information can be used to directly inform transplant center certification policie and interventions to maintain the organization human capital of the transplant centers. PUBLIC HEALTH RELEVANCE: The proposed research has important implications for public health as it addresses issues related to the quality, safety and efficiency of surgical care in organ transplantation. Results of this research would emphasize the need to design interventions and enact policies that would maintain organizational human capital of transplant centers improvement the quality and value of transplant procedures.