Association Between Organ Procurement Organization Social Network Centrality and Kidney Discard and Transplant Outcomes

Deceased donor kidneys from higher distressed communities are significantly less likely to be utilized for transplantation

The proportion of kidneys procured for transplantation but not utilized exceeds 20% in the United States. Factors associated with nonutilization are complex, and further understanding of novel causes are critically important. We used the national Scientific Registry of Transplant Recipients data (2010-2022) to evaluate associations of Distressed Community Index (DCI) of deceased donor residence and likelihood of kidney nonutilization (n = 209 413). Deceased donors from higher distressed communities were younger, had an increased history of hypertension and diabetes, were CDC high-risk, and had higher terminal creatinine and donation after brain death. Mechanisms and circumstances of death varied significantly by DCI. The proportion of kidney nonutilization was 19.9%, which increased by DCI quintile (Q1 = 18.1% to Q5 = 21.6%). The adjusted odds ratio of nonutilization from the highest quintile DCI communities was 1.22 (95% CI = 1.16-1.28; reference = lowest DCI), which persisted stratified by donor race. Donors from highly distressed communities were highly variable by the donor service area (range: 1%-51%; median = 21%). There was no increased risk for delayed graft function or death-censored graft loss by donor DCI but modest increased adjusted hazard for overall graft loss (high DCI = 1.05; 95% CI = 1.01-1.10; reference = lowest DCI). Results indicate that donor residential distress is associated with significantly higher rates of donor kidney nonutilization with notable regional variation and minimal impact on recipient outcomes.

Do Organizational Characteristics of Lung Procurement Operations Matter: The Association Between Transplant Center Centrality and Volume With Total Ischemic Time

BACKGROUND

To understand the association of 2 organizational characteristics of transplant center (TXC), volume and closeness centrality, with total ischemic time for deceased donor lung transplants in conjunction with the removal of donation service area (DSA) lung allocation policy. The organization of donor procurements has received increased attention since DSA was removed from allocation policy. Consistent with network theories of organization, organizational characteristics of a TXC could affect procurement efficiency, as volume and closeness centrality (measuring how connected a TXC is within the Organ Procurement and Transplantation Network) could be associated with total ischemic time. These associations could have changed because of the removal of DSA from allocation policy.

METHODS

We conducted a retrospective, pooled cross-sectional study of total ischemic time for nonperfused deceased donor lung transplants (n = 9281) between 2015 and 2019, using within-between regression.

RESULTS

Higher volume TXCs exhibited lower total ischemic times after the removal of DSA from lung allocation policy (P = 0.011); however, all TXCs that had increased volumes, after the removal of DSA from lung allocation policy, exhibited higher levels of total ischemic time (P ≤ 0.001). Before the removal of DSA, TXCs that had increased volumes exhibited lower levels of ischemic time (P ≤ 0.001). Both within and between closeness centrality exhibited u-shaped associations with total ischemic time (P = 0.012; P = 0.006) and the effect of closeness centrality on total ischemic time was different after DSA removal (P < 0.001).

CONCLUSIONS

Organizational characteristics were associated with the efficiency of deceased organ procurements. The effects on total ischemic time were dependent on whether DSA was used for lung allocation.

Greater complexity and monitoring of the new Kidney Allocation System: Implications and unintended consequences of concentric circle kidney allocation on network complexity

The deceased donor kidney allocation system in the United States has undergone several rounds of iterative changes, but these changes were not explicitly designed to address the geographic variation in access to transplantation. The new allocation system, expected to start in December 2020, changes the definition of "local allocation" from the Donation Service Area to 250 nautical mile circles originating from the donor hospital. While other solid organs have adopted a similar approach, the larger number of both kidney transplant centers and transplant candidates is likely to have different consequences. Here, we discuss the incredible increase in complexity in allocation, discuss some of the likely intended and unintended consequences, and propose metrics to monitor the new system.

Evaluating Spatial Associations in Inpatient Deaths Between Organ Procurement Organizations

To improve the measurement of organ procurement organization (OPO) performance, the Center for Medicare and Medicaid Services recently proposed using inpatient deaths defined as the eligible pool of organ donors within an OPO as patients 75 years or younger that died from any cause that would not preclude donation.

METHODS

To account for the geographic variation in OPO performance and organ availability across the United States, we utilized spatial analysis to appraise the newly proposed metric of inpatient deaths.

RESULTS

Using spatial clustering that accounts for geographic relationships between Organ Procurement Organizations, the top 5 causes of donation-eligible death, and inpatient deaths, we identified 4 unique OPO clusters. Each group had a distinct demographic composition, cause of death, and inpatient death pattern. In multivariate analysis accounting for these geographic relationships, the spatial clusters remained significantly associated with the outcome of inpatient deaths (P < 0.001) and were the best-fitting model compared with models without the spatial clusters; this suggests that further risk adjustment of inpatient deaths should include these geographic considerations.

CONCLUSIONS

This approach provides not only a manner to assess donor potential by improving risk adjustment but also an opportunity to further explore geographic and spatial relationships in the practice of organ transplantation and OPO performance.

Prediction of Kidney Allograft Discard Before Procurement: The Kidney Discard Risk Index

OBJECTIVES

There is an 18.9% discard rate among kidney allografts. Here, we aimed to determine predictors of kidney discard and construct an index to identify high-probability discard kidney allografts prior to procurement.

MATERIALS AND METHODS

A total of 102 246 potential kidney allograft donors from the Organ Procurement and Transplantation Network database were used in this analysis. The cohort was randomized into 2 groups. The training set included 67% of the cohort and was used to derive a predictive index for discard that comprised 21 factors identified by univariate and multivariate logistic regression analysis. The validation set included 33% and was used to internally validate the kidney discard risk index.

RESULTS

In 77.3% of donors, at least 1 kidney was used for transplant, whereas in 22.7% of donors, both kidneys were discarded. The kidney discard risk index was highly predictive of discard with a C statistic of 0.89 (0.88-0.89). The bottom 10th percentile had a discard rate of 0.73%, whereas the top 10th percentile had a discard rate of 83.65%. The 3 most predictive factors for discard were age, creatinine level, and hepatitis C antibody status.

CONCLUSIONS

We identified 21 factors predictive of discard prior to donor procurement and used these to develop a kidney discard risk index with a C statistic of 0.89.

Applications of network analysis to routinely collected health care data: a systematic review

Objective

To survey network analyses of datasets collected in the course of routine operations in health care settings and identify driving questions, methods, needs, and potential for future research.

Materials and Methods

A search strategy was designed to find studies that applied network analysis to routinely collected health care datasets and was adapted to 3 bibliographic databases. The results were grouped according to a thematic analysis of their settings, objectives, data, and methods. Each group received a methodological synthesis.

Results

The search found 189 distinct studies reported before August 2016. We manually partitioned the sample into 4 groups, which investigated institutional exchange, physician collaboration, clinical co-occurrence, and workplace interaction networks. Several robust and ongoing research programs were discerned within (and sometimes across) the groups. Little interaction was observed between these programs, despite conceptual and methodological similarities.

Discussion

We use the literature sample to inform a discussion of good practice at this methodological interface, including the concordance of motivations, study design, data, and tools and the validation and standardization of techniques. We then highlight instances of positive feedback between methodological development and knowledge domains and assess the overall cohesion of the sample.

Characteristics and Performance of Unilateral Kidney Transplants from Deceased Donors

BACKGROUND AND OBJECTIVES

The fraction of kidneys procured for transplant that are discarded is rising in the United States. Identifying donors from whom only one kidney was discarded allows us to control for donor traits and better assess reasons for organ discard.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We conducted a retrospective cohort study using United Network for Organ Sharing Standard Transplant Analysis and Research file data to identify deceased donors from whom two kidneys were procured and at least one was transplanted. Unilateral pairs were defined as kidney pairs from a single donor from whom one kidney was discarded ("unilateral discard") but the other was transplanted ("unilateral transplant"). Organ quality was estimated using the Kidney Donor Risk Index and Kidney Donor Profile Index (KDPI). We compared all-cause graft failure rates for unilateral transplants to those for bilateral transplant Kaplan-Meier methods, and life table methodology was used to evaluate 1-, 2-, 3-, and 5-year survival rates of transplants from bilateral and unilateral donors.

RESULTS

Compared with bilateral donors (i.e., both kidneys transplanted) (n=80,584), unilateral donors (i.e., only one kidney transplanted) (n=7625) had higher mean terminal creatinine (1.3±2.1 mg/dl versus 1.1±0.9 mg/dl) and KDPI (67%±25% versus 42%±27%), were older, and were more likely to have hypertension, diabetes, hepatitis C, terminal stroke, or meet Centers for Disease Control and Prevention high-risk donor criteria. Unilateral discards were primarily attributed to factors expected to be similar in both kidneys from a donor: biopsy findings (22%), no interested recipient (13%), and donor history (7%). Anatomic abnormalities (14%), organ damage (11%), and extended ischemia (6%) accounted for about 30% of discards, but were the commonest reasons among low KDPI kidneys. Among kidneys with KDPI≥60%, there was an incremental difference in allograft survival over time (for unilateral versus bilateral transplants, 1-year survival: 83% versus 87%; 3-year survival: 69% versus 73%; 5-year survival: 51% versus 58%).

CONCLUSIONS

A large number of discarded kidneys were procured from donors whose contralateral kidneys were transplanted with good post-transplant outcomes.