What is KDPI and does it matter?

-
The kidney donor profile index (KDPI)  is used in the new kidney allocation system to match the longevity of the kidney with that of the recipient to maximize the years of life gained through transplantation. It combines 10 donor factors into a single number that summarizes the potential risk of graft failure after kidney transplant. 

It is not intended to serve as the only metric for determining donor suitability. Indeed the C-statistic for this is 0.6, which is a little better than a coin toss. Many of the factors have no bearing on long-term function.  Pediatric en-bloc kidneys and dual kidneys from older donors will have very high KDPI even though they will work far better than a single adult kidney with KDPI<85. It is an improvement over the old system of standard criteria and extended criteria kidneys, but far from perfect. 

Given the poor relationship to outcomes, I do not place much value on this in my practice. In my experience the factors that are more predictive of a durable outcome are:

DONOR FACTORS:

  1. the donors instability and comorbidies ( diabetes, hypertension, icu support requirements) 
  2. the kidney biopsy ( glomerculosclerosis, interstitial fibrosis, arteriosclerosis)
  3. cold ischemia time (time from clamping the vessels in the donor to restoring blood flow in the recipient) 
  4. the kidneys performance on the pulsatile perfusion machine 
RECIPIENT FACTORS:
  1. recipients vascular disease (most kidneys are lost because the recipient dies with a functioning kidney)
  2. recipients ability to tolerate a rejection or infection episode. 
  3. recipients compliance with medical care ( taking care of diabetes, blood pressure, immunosuppressants)
  4. regular followup with their transplant center. 
  5. good insurance and solid support system 
The newer non-nephrotoxic immunosuppressant, Nulojix, has shown better graft function and increased patient survival at 7 year. This is used in more than half of the patients receiving a transplant at the Iowa Methodist Transplant Center. The other patients are maintained on tacrolimus based immunosuppression. 

So, KDPI is an improvement on the older system but it does not determine longterm kidney function. I do no place a too much emphasis on KDPI when evaluating kidney offers for transplant. The donor and recipient factors I have outlined above are far more important. 


pediatric en-bloc kidneys and dual kidney have very high KDPI despite having better long-term function compared to a single kidney transplant. 








Location: Des Moines, IA, USA

Comments

Post a Comment

Popular posts from this blog

Immunosuppression: why and how?

-
Image
Background: Care is taken to perform compatible transplants by checking antibodies to blood (ABO) and tissue (HLA) antigens.The rejection of transplanted organs is caused by the activation of lymphocytes. HLA class 1 molecules are present on all nucleated cells and help the immune system to distinguish self from non-self.  HLA class 2 molecules are only present on antigen presenting cells (dendritic cells, monocytes, macrophages). The dendritic cells of the donor tissue migrate to the recipients lymphoid tissue and present them to the recipients lymphocytes, activating the overwhelming armamentarium of of the immune system. All blood cells arise from a common stem cell but the lymphocytes follow a different lineage.  Once activated, the T lymphocytes differentiate into cytotoxic T cells, tumor suppressor cells, and T-helper cells;  The B lymphocytes become plasma cells and memory cells.  There are essentially two types of rejection although a mixed patt...
Read more

I have a history of cancer, can I still get a transplant?

-
Image
Patients on dialysis have an increased risk of cancer compared to the general population but there is no evidence to support more intensive screening of potential transplant recipients above that suggested for the general population. Cancer is responsible for 9–12% of deaths in renal transplant recipients. Post-transplant immunosuppression likely inhibits surveillance mechanisms that otherwise counteract the development of malignant cell growth. In fact, the risk of a developing new cancers exceeds the risk of recurrence of the original malignancy after transplantation.  Kidney failure patients that have been successfully treated for their cancer are generally considered to be suitable candidates for  transplantation. Tumor biology varies considerably between cancers and even within the same cancer, therefore a blanket recommendation for malignancy overall would not be valid. The current guidelines are based primarily on registry data from the Isra...
Read more