The aggressive phenotype: center-level patterns in the utilization of suboptimal kidneys

Area of Science:

• Nephrology
• Transplant Surgery
• Health Services Research

Background:

• Suboptimal kidneys, despite poorer outcomes, are utilized variably due to differing wait times and wait-list mortality.
• It remains unclear if transplant centers exhibit an aggressive phenotype in using various types of suboptimal grafts concurrently.
• Understanding center characteristics associated with aggressive suboptimal graft utilization is crucial for optimizing kidney transplant practices.

Purpose of the Study:

• To investigate whether transplant centers' aggressive use of one type of suboptimal kidney graft correlates with the aggressive use of other types.
• To identify center-specific characteristics associated with an overall aggressive phenotype in utilizing suboptimal kidney grafts.
• To explore the impact of wait-list dynamics, organ availability, and center operational factors on transplant aggressiveness.

Main Methods:

• Utilized United Network for Organ Sharing (UNOS) data from 2005-2009 for adult kidney transplant recipients.
• Aggregated data to the center level and assigned an aggressiveness score based on suboptimal graft usage.
• Employed cluster analysis to identify patterns in aggressive utilization across different graft types and correlated aggressiveness with center characteristics.

Main Results:

• Aggressiveness in suboptimal kidney utilization was associated with wait-list size, organ shortage, and longer waiting times.
• Higher transplant volumes did not consistently correlate with aggressiveness, unlike in lower-volume centers.
• Aggressive centers were predominantly located in specific geographic regions (2 and 9), and none were found in single-center Organ Procurement Organizations (OPOs).

Conclusions:

• Wait-list size, waiting times, geographic region, and OPO competition are significant drivers of center-level aggressiveness in utilizing suboptimal kidney grafts.
• While some centers show consistent aggressive or non-aggressive patterns, others exhibit intermediate phenotypes with varied suboptimal kidney usage.
• These findings highlight the complex interplay of systemic and operational factors influencing organ allocation strategies and transplant center behavior.