Kidney Disease Belt Mimics Stroke Belt, With Higher Organ Needs

Nancy A. Melville

March 31, 2020

Consistent with the known distinction of a region in the southeastern United States known as the "stroke belt", a corresponding "end-stage renal disease (ESRD) belt" exists, where the prevalence of advanced kidney disease is high and the supply of donor organs is low, new research concludes.

ESRD is a known risk factor for stroke and its high prevalence in the region is not unexpected, however unique implications — including the burden on the kidney donation supply — makes the separate identification of an ESRD belt important, says the lead researcher.

"While it has previously been shown that the Deep South has a high prevalence of ESRD, to our knowledge, this is the first analysis to formally explore the association between ESRD and stroke prevalence," Rhiannon Reed, DrPH, an assistant professor of surgery at the Comprehensive Transplant Institute, University of Alabama at Birmingham, told Medscape Medical News.

And it shows "wide geographic variation in ESRD period prevalence per million adult population, with increased burden concentrated in the southeast," she said.

And in a separate analysis, Reed and colleagues found that states with a higher prevalence of ESRD had a lower rate of kidney transplant.

"If an area has a high burden of health factors that will ultimately make individuals ineligible for donation, there will be fewer organs available to meet the need for transplantation," she explained.

"A national allocation system could alleviate geographic disparities and maintain an equitable supply/demand ratio throughout the country."

Five Southern States Make Up ESRD Belt

For the first cross-sectional study, presented virtually this month at the Cutting Edge of Transplantation (CEOT) meeting in Phoenix, Arizona, Reed and colleagues evaluated data from the United States Renal Data System (USRDS) to estimate the prevalence of adult, transplant-eligible ESRD patients in 2016.

They identified 450,828 patients with ESRD in total, with US prevalence rates ranging from 3430 patients per million in Mississippi to only about 808 patients per million in Vermont and New Hampshire.

The burden was significantly increased in the southeast, and of the 10 states with the highest ESRD prevalence, five were also located in the stroke belt. In addition to Mississippi, they include Louisiana (2962 patients per million), Alabama (2648 patients per million), Georgia (2740 patients per million), and South Carolina (2673 patients per million).

And the prevalence of ESRD was significantly correlated with history of stroke at the state level (P < .001), the authors note.

"These findings of overlapping disease underscore the need to consider disease burden in conversations regarding organ supply and allocation, to ensure equitable access to transplantation and prevention of future comorbidity," they advise.

High Rates of ESRD Correlate With Low Organ Availability, Transplant Rates

In a separate analysis also presented at the meeting, Reed and colleagues looked at transplant rates in states according to prevalence of ESRD and found evidence that states in the ESRD belt, and others with a higher prevalence of ESRD, in fact had lower transplant rates, defined as the number of adult deceased donor kidney transplantations per 100 eligible candidates with ESRD.

In the study of 364,358 transplant-eligible patients with ESRD, using USRDS data, the state prevalence rates of ESRD ranged from 3528 patients per million in Washington, DC, to 627 patients per million in Vermont, with a mean of 1477 patients per million (SD, 592).

Transplant rates, meanwhile, ranged from 6.24 in Iowa to 1.55 in Arkansas (mean, 3.38).

The state-level prevalence of eligible ESRD patients per million was strongly negatively correlated with the state transplant rate (P < .001).

"Higher demand for kidney transplantation is associated with lower supply of deceased donor kidney transplantation, suggesting that current geographic inequities will not improve and may intensify," the authors report.

They note that the kidney allocation system that was implemented in 2014 does not account for the potential local supply based on the health characteristics of the population within a donation service area.

Reed explained: "The high burden of ESRD in this area is likely attributed to the high prevalence of minority race/ethnicity, given that African Americans are at greatest risk for development of ESRD, as well as high prevalence of other comorbid conditions associated with increased risk of ESRD, specifically obesity, hypertension, and diabetes mellitus."

In previous research, Reed and colleagues demonstrated the very factors that increase organ demand also decrease supply, as organ donors — both living and deceased — are drawn from the surrounding population.

"As such, we believe it is crucial to consider the health of the population when discussing organ allocation policies," they write.

The authors have reported no relevant financial relationships.

Cutting Edge of Transplantation (CEOT) Meeting. Abstracts 15 and 16. Presented March 5, 2020.

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