# ESRD-specific physiologic age: improving geriatric transplant prognostication

> **NIH NIH R01** · JOHNS HOPKINS UNIVERSITY · 2020 · $763,394

## Abstract

Older adults with end stage renal disease (ESRD) who receive kidney transplantation (KT) double their life
expectancy. The new kidney allocation system, designed to better match longevity of recipients and allografts,
has been in effect for 2 years. During this time, access to KT among older adults has plummeted; with rates
declining 10% for candidates aged 61-70 and 24% for those aged >70. The core problem is that the United
Network for Organ Sharing (UNOS) decided that longevity matching for the new allocation system would be
based on Estimated Post-Transplant Survival (EPTS), a simple model that only includes chronologic age,
diabetes, time on dialysis, and prior transplant. EPTS has poor predictive power among older recipients; the c-
statistic of EPTS for older recipients is 0.59, which is lower than the c-statistic of 0.67 for younger recipients.
We hypothesize that a measure of physiologic reserve will more accurately stratify risk among older KT
recipients than chronologic age. Our preliminary work suggests that the Fried frailty phenotype, is associated
with poor post-KT outcomes. While our findings are encouraging, it is unlikely that this construct captures all
the dimensions of physiologic reserve associated with ESRD. It is likely that some attributes of the Fried frailty
phenotype are not even relevant for this population. We believe an ESRD-specific measure of physiologic
reserve, beyond frailty and/or other conventional measures, would greatly improve risk stratification.
UNOS and the transplant community might be reluctant to add a new variable to the purposefully parsimonious
EPTS score, which was debated for 15 years. Our novel approach, supported by the upcoming UNOS
president, is to replace chronologic age with physiologic age in the model. The overarching goal of our
research will be to develop a physiologic age calculator and test whether replacing chronologic age with
physiologic age improves prognostication for older adults with ESRD.
To achieve these goals, we will leverage existing data and collect new data within an ongoing longitudinal
cohort study of 5,500 ESRD patients. We will abstract new data on components of physiologic reserve from the
parent study and enroll an additional 2,342 new ESRD patients in an ancillary study which will directly measure
the physiologic reserve components that cannot be abstracted. We will test the following aims: 1) To elicit and
evaluate novel constructs that might quantify physiologic reserve in older ESRD patients; 2) To create a valid,
reliable, and generalizable measure of physiologic reserve for ESRD patients; 3) To test if replacing
chronologic age with physiologic age improves prognostication in older recipients.
This work would improve prognostication for older adults with ESRD, which would benefit patient selection,
informed consent, and case-mix adjusted transplant center report cards. Our novel approach to replacing
chronologic age with physiologic age has the support of UN...

## Key facts

- **NIH application ID:** 9934961
- **Project number:** 5R01AG055781-04
- **Recipient organization:** JOHNS HOPKINS UNIVERSITY
- **Principal Investigator:** Mara A. McAdams DeMarco
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2020
- **Award amount:** $763,394
- **Award type:** 5
- **Project period:** 2017-09-01 → 2022-05-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/9934961

## Citation

> US National Institutes of Health, RePORTER application 9934961, ESRD-specific physiologic age: improving geriatric transplant prognostication (5R01AG055781-04). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/9934961. Licensed CC0.

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