Geographical rural status and health outcomes in pediatric liver transplantation: an analysis of 6 years of national United Network of Organ Sharing Data

Ambient air pollution is associated with graft failure/death in pediatric liver transplant recipients

Children exposed to disproportionately higher levels of air pollution experience worse health outcomes. In this population-based, observational registry study, we examine the association between air pollution and graft failure/death in children following liver transplantation (LT) in the US. We modeled the associations between air pollution (PM2.5) levels localized to the patient's ZIP code at the time of transplant and graft failure or death using Cox proportional-hazards models in pediatric LT recipients aged <19 years in the US from 2005-2015. In univariable analysis, high neighborhood PM2.5 was associated with a 56% increased hazard of graft failure/death (HR: 1.56; 95% CI: 1.32, 1.83; P < .001). In multivariable analysis, high neighborhood PM2.5 was associated with a 54% increased risk of graft failure/death (HR: 1.54; 95% CI: 1.29, 1.83; P < .001) after adjusting for race as a proxy for racism, insurance status, rurality, and neighborhood socioeconomic deprivation. Children living in high air pollution neighborhoods have an increased risk of graft failure and death posttransplant, even after controlling for sociodemographic variables. Our findings add further evidence that air pollution contributes to adverse health outcomes for children posttransplant and lay the groundwork for future studies to evaluate underlying mechanisms linking PM2.5 to adverse LT outcomes.

Geographic barriers to children's surgical care: A systematic review of existing evidence

BACKGROUND

Ensuring that children have access to timely and appropriate surgical care is a vital component of comprehensive pediatric care. This study systematically reviews the existing evidence related to geographic barriers in children's surgery.

METHODS

Medline and Scopus databases were searched for any English language studies that examined associations between geographic burden (rural residence or distance to care) and a quantifiable outcome within pediatric surgical subspecialties. Two independent reviewers extracted data from each study.

RESULTS

From 6331 studies screened, 22 studies met inclusion criteria. Most studies were retrospective analyses and conducted in the U.S. or Canada (14 and three studies, respectively); five were conducted outside North America. In transplant surgery (seven studies), greater distance from a transplant center was associated with higher waitlist mortality prior to kidney and liver transplantation, although graft outcomes were generally similar. In congenital cardiac surgery (five studies), greater travel was associated with higher neonatal mortality and older age at surgery but not with post-operative outcomes. In general surgery (eight studies), rural residence was associated with increased rates of perforated appendicitis, higher frequency of negative appendectomy, and increased length of stay after appendectomy. In orthopedic surgery (one study), rurality was associated with decreased post-operative satisfaction. No evidence for disparate outcomes based upon distance or rurality was identified in neurosurgery (one study).

CONCLUSIONS

Substantial evidence suggests that geographic barriers impact the receipt of surgical care among children, particularly with regard to transplantation, congenital cardiac surgery, and appendicitis.

Living Donor Liver Transplant Center Volume Influences Waiting List Survival Among Children Listed for Liver Transplantation

BACKGROUND

Pediatric living donor liver transplantation (LDLT) remains infrequently performed in the United States and localized to a few centers. This study aimed to compare pediatric waiting list and posttransplant outcomes by LDLT center volume.

METHODS

The Scientific Registry of Transplant Recipients/Organ Procurement and Transplantation Network database was retrospectively reviewed for all pediatric (age <18 y) liver transplant candidates listed between January 1, 2009, and December 31, 2019. The average annual number of LDLT, deceased donor partial liver transplant (DDPLT), and overall (ie, LDLT + DDPLT + whole liver transplants) pediatric liver transplants performed by each transplant center during the study period was calculated.

RESULTS

Of 88 transplant centers, only 44 (50%) performed at least 1 pediatric LDLT during the study period. LDLT, DDPLT, and overall transplant center volume were all positively correlated. LDLT center volume was protective against waiting list dropout after adjusting for confounding variables (adjusted hazard ratio, 0.92; 95% confidence interval, 0.86-0.97; P = 0.004), whereas DDPLT and overall center volume were not (P > 0.05); however, DDPLT center volume was significantly protective against both recipient death and graft loss, whereas overall volume was only protective against graft loss and LDLT volume was not protective for either.

CONCLUSIONS

High-volume pediatric LDLT center can improve waiting list survival, whereas DDPLT and overall volume are associated with posttransplant survival. Expertise in all types of pediatric liver transplant options is important to optimize outcomes.

Association Between Neighborhood-level Socioeconomic Deprivation and the Medication Level Variability Index for Children Following Liver Transplantation

BACKGROUND

Neighborhood socioeconomic deprivation is associated with adverse health outcomes. We sought to determine if neighborhood socioeconomic deprivation was associated with adherence to immunosuppressive medications after liver transplantation.

METHODS

We conducted a secondary analysis of a multicenter, prospective cohort of children enrolled in the medication adherence in children who had a liver transplant study (enrollment 2010-2013). Participants (N = 271) received a liver transplant ≥1 year before enrollment and were subsequently treated with tacrolimus. The primary exposure, connected to geocoded participant home addresses, was a neighborhood socioeconomic deprivation index (range 0-1, higher indicates more deprivation). The primary outcome was the medication level variability index (MLVI), a surrogate measure of adherence to immunosuppression in pediatric liver transplant recipients. Higher MLVI indicates worse adherence behavior; values ≥2.5 are predictive of late allograft rejection.

RESULTS

There was a 5% increase in MLVI for each 0.1 increase in deprivation index (95% confidence interval, -1% to 11%; P = 0.08). Roughly 24% of participants from the most deprived quartile had an MLVI ≥2.5 compared with 12% in the remaining 3 quartiles (P = 0.018). Black children were more likely to have high MLVI even after adjusting for deprivation (adjusted odds ratio 4.0 95% confidence interval, 1.7-10.6).

CONCLUSIONS

This is the first study to evaluate associations between neighborhood socioeconomic deprivation and an objective surrogate measure of medication adherence in children posttransplant. These findings suggest that neighborhood context may be an important consideration when assessing adherence. Differential rates of medication adherence may partly explain links between neighborhood factors and adverse health outcomes following pediatric liver transplantation.

Distance is associated with mortality on the waitlist in pediatric liver transplantation

The distance to liver transplant centers affects outcomes in adult liver transplantation. Because pediatric patients are particularly vulnerable, we hypothesized that distance adversely affects the time to transplantation and waitlist mortality. The SRTR was queried for isolated pediatric liver transplant registrants (under age 18) with valid ZIP code information from 2003 to 2012. Distance was measured from home ZIP code to listing transplant center. Competing events analysis, adjusted for demographic factors, indication, and PELD, was undertaken for transplantation and death while on the waitlist. The median distance to listing transplant center for 6924 children was 65 (IQR 17.5-189) miles. Median distance traveled increased by listing volume (73.9 vs 33.8 miles, highest vs lowest volume quartile, P<.001 for trend) and varied across the country. Longer distance was not associated with time to transplantation (HR 0.99, longest vs shortest distance quartile, P=.80), but was associated with increased mortality (HR 1.75, P<.001). Larger centers attract patients from a distance, while smaller centers serve local populations. Increasing distance is associated with a higher risk of waitlist death, which may reflect decreased access to specialist and tertiary care associated with a transplant center.