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.
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.