Better Understanding the Disparity Associated With Black Race in Heart Transplant Outcomes: A National Registry Analysis

BACKGROUND

Black heart transplant recipients have higher risk of mortality than White recipients. Better understanding of this disparity, including subgroups most affected and timing of the highest risk, is necessary to improve care of Black recipients. We hypothesize that this disparity may be most pronounced among young recipients, as barriers to care like socioeconomic factors may be particularly salient in a younger population and lead to higher early risk of mortality.

METHODS

We studied 22 997 adult heart transplant recipients using the Scientific Registry of Transplant Recipients data from January 2005 to 2017 using Cox regression models adjusted for recipient, donor, and transplant characteristics.

RESULTS

Among recipients aged 18 to 30 years, Black recipients had 2.05-fold (95% CI, 1.67-2.51) higher risk of mortality compared with non-Black recipients (P<0.001, interaction P<0.001); however, the risk was significant only in the first year post-transplant (first year: adjusted hazard ratio, 2.30 [95% CI, 1.60-3.31], P<0.001; after first year: adjusted hazard ratio, 0.84 [95% CI, 0.54-1.29]; P=0.4). This association was attenuated among recipients aged 31 to 40 and 41 to 60 years, in whom Black recipients had 1.53-fold ([95% CI, 1.25-1.89] P<0.001) and 1.20-fold ([95% CI, 1.09-1.33] P<0.001) higher risk of mortality. Among recipients aged 61 to 80 years, no significant association was seen with Black race (adjusted hazard ratio, 1.12 [95% CI, 0.97-1.29]; P=0.1).

CONCLUSIONS

Young Black recipients have a high risk of mortality in the first year after heart transplant, which has been masked in decades of research looking at disparities in aggregate. To reduce overall racial disparities, clinical research moving forward should focus on targeted interventions for young Black recipients during this period.

Characterizing the landscape and impact of infections following kidney transplantation

Infections remain a major threat to successful kidney transplantation (KT). To characterize the landscape and impact of post-KT infections in the modern era, we used United States Renal Data System (USRDS) data linked to the Scientific Registry of Transplant Recipients (SRTR) to study 141 661 Medicare-primary kidney transplant recipients from January 1, 1999 to December 31, 2014. Infection diagnoses were ascertained by International Classification of Diseases, Ninth Revision (ICD-9) codes. The cumulative incidence of a post-KT infection was 36.9% at 3 months, 53.7% at 1 year, and 78.0% at 5 years. The most common infections were urinary tract infection (UTI; 46.8%) and pneumonia (28.2%). Five-year mortality for kidney transplant recipients who developed an infection was 24.9% vs 7.9% for those who did not, and 5-year death-censored graft failure (DCGF) was 20.6% vs 10.1% (P < .001). This translated to a 2.22-fold higher mortality risk (adjusted hazard ratio [aHR]: _2.15 2.22_2.29 , P < .001) and 1.92-fold higher DCGF risk (aHR: _1.84 1.91_1.98 , P < .001) for kidney transplant recipients who developed an infection, although the magnitude of this higher risk varied across infection types (for example, 3.11-fold higher mortality risk for sepsis vs 1.62-fold for a UTI). Post-KT infections are common and substantially impact mortality and DCGF, even in the modern era. Kidney transplant recipients at high risk for infections might benefit from enhanced surveillance or follow-up to mitigate these risks.

Changes in offer and acceptance patterns for pediatric kidney transplant candidates under the new Kidney Allocation System

Stakeholders have expressed concerns regarding decreased deceased donor kidney transplant (DDKT) rates for pediatric candidates under the Kidney Allocation System (KAS). To better understand what might be driving this, we studied Scientific Registry of Transplant Recipients kidney offer data for 3642 pediatric (age <18 years) kidney-only transplant candidates between December 31, 2012 to December 3, 2014 (pre-KAS) and December 4, 2014 to January 6, 2017 (post-KAS). We used negative binomial regression and multilevel logistic regression to compare offer and acceptance rates pre- and post-KAS. We stratified by donor age (<18, 18-34, and 35+ years) and KDPI (<35% and ≥35%) to reflect differing allocation prioritization pre-KAS and post-KAS. As might be expected from prioritization changes, post-KAS candidates were less likely to receive offers for donors 18-34 years old with KDPI ≥ 35% (adjusted incidence rate ratio [aIRR]: 0.18 0.210.25 , P < .001), and more likely to receive offers for donors 18-34 years old and KDPI < 35% (aIRR: 1.12 1.201.29 , P < .001). However, offer acceptance practices also changed post-KAS: kidneys from donors 18-34 years old and KDPI < 35% were 23% less likely to be accepted post-KAS (adjusted odds ratio: 0.61 0.770.98 , P = .03). Using kidneys from donors 18-34 years old with KDPI < 35% post-KAS to the same extent they were used pre-KAS might be an effective strategy to mitigate any decrease in DDKT rates for pediatric candidates.

How do highly sensitized patients get kidney transplants in the United States? Trends over the last decade

Prioritization of highly sensitized (HS) candidates under the kidney allocation system (KAS) and growth of large, multicenter kidney-paired donation (KPD) clearinghouses have broadened the transplant modalities available to HS candidates. To quantify temporal trends in utilization of these modalities, we used SRTR data from 2009 to 2017 to study 39 907 adult HS (cPRA ≥ 80%) waitlisted candidates and 19 003 recipients. We used competing risks regression to quantify temporal trends in likelihood of DDKT, KPD, and non-KPD LDKT for HS candidates (Era 1: January 1, 2009-December 31, 2011; Era 2: January 1, 2012-December 3, 2014; Era 3: December 4, 2014-December 31, 2017). Although the likelihood of DDKT and KPD increased over time for all HS candidates (adjusted subhazard ratio [aSHR] Era 3 vs 1 for DDKT: 1.74 1.851.97 , P < .001 and for KPD: 1.70 2.202.84 , P < .001), the likelihood of non-KPD LDKT decreased (aSHR: 0.69 0.820.97 , P = .02). However, these changes affected HS recipients differently based on cPRA. Among recipients, more cPRA 98%-99.9% and 99.9%+ recipients underwent DDKT (96.2% in Era 3% vs 59.1% in Era 1 for cPRA 99.9%+), whereas fewer underwent non-KPD LDKT (1.9% vs 30.9%) or KPD (2.0% vs 10.0%). Although KAS increased DDKT likelihood for the most HS candidates, it also decreased the use of non-KPD LDKT to transplant cPRA 98%+ candidates.

Assessment of Use of Arteriovenous Graft vs Arteriovenous Fistula for First-time Permanent Hemodialysis Access

Importance

Initial hemodialysis access with arteriovenous fistula (AVF) is associated with superior clinical outcomes compared with arteriovenous graft (AVG) and should be the procedure of choice whenever possible. To address the national underuse of AVF in the United States, the Centers for Medicare & Medicaid has established an AVF goal of 66% or greater in 2009.

Objective

To explore contemporary practice patterns and physician characteristics associated with high AVG use compared with AVF use.

Design, Setting, and Participants

This review of 100% Medicare Carrier claims between January 1, 2016, and December 31, 2017, includes both inpatient and outpatient Medicare claims data. All patients undergoing initial permanent hemodialysis access placement with an AVF or AVG were included. All surgeons performing more than 10 hemodialysis access procedures during the study period were analyzed.

Exposures

Placement of an AVF or AVG for initial permanent hemodialysis access.

Main Outcomes and Measures

A surgeon-level AVG (vs AVF) use rate was calculated for all included surgeons. Hierarchical logistic regression modeling was used to identify patient-level and surgeon-level factors associated with AVG use.

Results

A total of 85 320 patients (median age, 70 [range, 18-103] years; 47 370 men [55.5%]) underwent first-time hemodialysis access placement, of whom 66 489 (77.9%) had an AVF and 18 831 (22.1%) had an AVG. Among the 2397 surgeons who performed more than 10 procedures per year, the median surgeon level AVG use rate was 18.2% (range, 0.0%-96.4%). However, 498 surgeons (20.8%) had an AVG use rate greater than 34%. After accounting for patient characteristics, surgeon factors that were independently associated with AVG use included more than 30 years of clinical practice (vs 21-30 years; odds ratio, 0.85 [95% CI, 0.75-0.96]), metropolitan setting (odds ratio, 1.25 [95% CI, 1.02-1.54]), and vascular surgery specialty (vs general surgery; odds ratio, 0.77 [95% CI, 0.69-0.86]). Surgeons in the Northeast region had the lowest rate of AVG use (vs the South; odds ratio, 0.83 [95% CI, 0.73-0.96]). First-time hemodialysis access benchmarking reports for individual surgeons were created for potential distribution.

Conclusions and Relevance

In this study, one-fifth of surgeons had an AVG use rate above the recommended best practices guideline of 34%. Although some of these differences may be explained by patient referral practices, sharing benchmarked performance data with surgeons could be an actionable step in achieving more high-value care in hemodialysis access surgery.

Pediatric deceased donor kidney transplant outcomes under the Kidney Allocation System

The Kidney Allocation System (KAS) has resulted in fewer pediatric kidneys being allocated to pediatric deceased donor kidney transplant (pDDKT) recipients. This had prompted concerns that post-pDDKT outcomes may worsen. To study this, we used SRTR data to compare the outcomes of 953 pre-KAS pDDKT (age <18 years) recipients (December 4, 2012-December 3, 2014) with the outcomes of 934 post-KAS pDDKT recipients (December 4, 2014-December 3, 2016). We analyzed mortality and graft loss by using Cox regression, delayed graft function (DGF) by using logistic regression, and length of stay (LOS) by using negative binomial regression. Post-KAS recipients had longer pretransplant dialysis times (median 1.26 vs 1.07 years, P = .02) and were more often cPRA 100% (2.0% vs 0.1%, P = .001). Post-KAS recipients had less graft loss than pre-KAS recipients (hazard ratio [HR]: _0.35 0.54_0.83 , P = .005) but no statistically significant differences in mortality (HR: _0.29 0.72_1.83 , P = .5), DGF (odds ratio: _0.93 1.32_1.93 , P = .2), and LOS (LOS ratio: _0.96 1.06_1.19 , P = .4). After adjusting for donor-recipient characteristics, there were no statistically significant post-KAS differences in mortality (adjusted HR: _0.37 1.04_2.92 , P = .9), DGF (adjusted odds ratio: _0.94 1.41_2.13 , P = .1), or LOS (adjusted LOS ratio: _0.93 1.04_1.16 , P = .5). However, post-KAS pDDKT recipients still had less graft loss (adjusted HR: _0.38 0.59_0.91 , P = .02). KAS has had a mixed effect on short-term posttransplant outcomes for pDDKT recipients, although our results are limited by only 2 years of posttransplant follow-up.

Endovascular repair of tortuous recurrent femoral-popliteal aneurysm in a patient with Loeys-Dietz syndrome

Loeys-Dietz syndrome is a rare connective tissue disorder with widespread arterial tortuosity and aneurysms. This syndrome is most notable for its aortic disease, including aortic root dilation and aortic dissection or rupture. Although not as well studied, peripheral artery aneurysms are a prevalent concurrent manifestation and have previously been repaired with both open and endovascular approaches. There are minimal data about the durability and technical considerations of endovascular repair in this disease. We report a case of a patient who developed an extremely tortuous recurrent femoral-popliteal artery aneurysm secondary to aneurysmal degeneration around previously placed stents that was treated with an endovascular approach.