Elderly renal transplant recipients have worse outcomes with an expanded-criteria donor (ECD) kidney than a standard-criteria donor (SCD) kidney, according to a new study. They also had worse outcomes than younger ECD kidney recipients.
“These findings may have implications in kidney allocation policy developments that encourage placement of ECD kidneys for older recipients,” the study investigators reported in the Clinical Journal of the American Society of Nephrology (2012;7:1163-1171).
Joshua D. Mezrich, MD, and colleagues at the University of Wisconsin School of Medicine in Madison reviewed data from all primary deceased-donor kidney transplantations performed from 2000 to 2005 at their center. The study population included 189 recipients aged 60 years and older (group 1) and 370 recipients aged 40-59 years (group 2). In group 1, 96 patients received an ECD kidney and 93 received an SCD kidney. In group 2, 105 received an ECD kidney and 265 received an SCD kidney.
In group 1, recipients of ECD kidneys had one-, three-, and five-year graft survival rates of 72%, 59%, and 54%, respectively, whereas the rates for recipients of SCD kidneys were 92%, 72%, and 69%, respectively. The rates for patient survival were 77%, 69%, and 61%, respectively, for ECD kidney recipients, compared with 95%, 79%, and 76% for SCD kidney recipients. The differences in graft and patient survival were statistically significant.
In group 2, recipients of ECD kidneys had one-, three-, and five-year graft survival rates of 88%, 73%, and 56%, respectively, and recipients of SCD kidneys had rates of 91%, 83%, and 70%, respectively. ECD kidney recipients had one-, three-, and five-year patient survival rates of 92%, 83%, and 77%, respectively, and SCD kidney recipients had rates of 95%, 89%, and 79%.
Among patients in group 1, receiving an ECD kidney was associated with a twofold increased risk of both graft loss and patient death compared with receiving an SCD kidney, after adjusting for multiple variables.
In addition, in group 1, recipients of ECD kidneys had a significantly higher proportion of acute rejection episodes than recipients of SCD kidneys (35% vs. 17%). They also had significantly more pneumonia cases (35% vs. 22%), opportunistic infections (60% vs. 27%), and readmissions (80% vs. 66%).
“This study sheds light on the importance of appropriately matching organs with recipients, particularly for ECD organs,” the authors wrote. “This can be difficult in regions where multiple transplant centers are represented by a single organ procurement organization. Modifying allocation rules for ECD kidneys should be considered in an effort to match the appropriate kidney to the appropriate recipient, and still maximize the amount of transportation time for the kidney.”
Dr. Mezrich and his colleagues acknowledged that their study is limited by its retrospective, nonrandomized design and its inclusion of patients from only a single center. “Nevertheless, it has allowed us to better understand how best to use the kidneys available to our patients,” they stated.