TRENDS IN ESTIMATED GLOMERULAR FILTRATION RATE DURING YEARS 1 TO 5 POST-TRANSPLANT, DATA FROM THE PREDICTING OUTCOMES IN RENAL TRANSPLANT (PORT) INTERNATIONAL DATA COLLABORATION

EPIDEMIOLOGY AND CLINICAL OUTCOMES

J. Snyder¹, J. Liu², M. Skeans¹, A. Israni¹, G. L’italian³, B. Kasiske^2
1, Chronic Disease Research Group, Minneapolis/UNITED STATES OF AMERICA, ², Chronic Disease Research Group, Minneapolis/MN/UNITED STATES OF AMERICA, ³, Bristol-Myers Squibb Company, Wallingford/CT/UNITED STATES OF AMERICA

Body: Introduction: Serum creatinine-based estimation of glomerular filtration rate (eGFR) is the standard marker for monitoring graft function. Monitoring declining eGFR can help clinicians anticipate long-term prognoses. Methods: We estimated rates of eGFR decline in patients whose allografts survived 1 year post-transplant (N=13,567 patients from 11 transplant centers in the Patient Outcomes in Renal Transplantation [PORT] international database). GFR was estimated using the abbreviated Modification of Diet in Renal Disease Study equation. eGFR at 1 year post-transplant was used to stratify patients by KDOQI CKD-staging category, with an additional cutpoint at 45 (90+, 60-89, 45-59, 30-44, 15-29, <15). eGFR at years 2, 3, 4, and 5 were used to estimate mean rate of decline per year stratified by first-year eGFR group. Figure 1 shows mean eGFR at years 1-5, stratified by eGFR group at year 1. A longitudinal mixed model was used to estimate mean rates of decline within strata of first year eGFR (Table 1).

eGFR at 1 year	Slope (ml/min/1.73m2 Per Patient Per Year)
90+	-8.4636
60 -89	-2.9628
45-59	-1.4124
30-44	-0.9974
15-29	-1.1324
<15	-1.9188

Results: One-year eGFR was between 45 and 60 for the largest proportion of patients (34%), in whom eGFR declined by 1.4 ml/min/1.73 m² per year. The lowest rate of decline, approximately 1 ml/min/1.73 m² per year, was seen for in the 30-44 group. The small percentage of patients with eGFR above 90 at 1 year experienced the most rapid declines. This could be a statistical phenomenon of regression toward the mean, or may be due to underlying poor health that is not accounted for in serum creatinine-based GFR estimation. Conclusion: The population with high eGFR deserves further study. Kidney allograft function declines at similar rates in patients with eGFR 0-60 mL/min at 1 year.

Disclosure: All authors have declared no conflicts of interest.