Response letter to the public commentary period on proposed modifications to UNOS Policy 3.5.9. (the point system for kidney allocation).

September 5, 1997

Date posted on the Web: September 15, 1997

To: The Board of Directors, United Network for Organ Sharing

From: The American Society of Transplant Physician

Re: Proposed modifications to UNOS Policy 3.5.9. (The Point System for Kidney Allocation)

The American Society of Transplant Physicians feels that the proposed modifications in the Point System for Kidney Allocation will go a long way toward guaranteeing equity in the organ distribution system; however, we feel that they require further revision. We agree with the need for uniform listing criteria, and for the need to apply the same standard to all patients, but we recommend exempting children less than 18 years of age. A substantial body of scientific evidence suggests that children benefit uniquely from renal transplantation. At the Standardized Listing Criteria Consensus Conference (sponsored by ASTP, UNOS, and the NIH, and held in Washington DC, January 30, 1997) there was unanimity of opinion that children should be given preferential consideration in any listing criteria.

In addition, we strongly advocate that a more reliable and more reproducible method to measure renal function be used as the determining criteria for listing. Creatinine clearances are notoriously inaccurate, and can easily be manipulated by under-collecting the urine sample. If creatinine clearance is used as a listing criteria, then a mechanism for validating the completeness of the collection should be included, e.g., urine creatinine excretion adjusted for gender, height, weight, etc.

The Cockroft-Gault method has not been extensively validated in populations of patients likely to be affected by these listing criteria, and data presented at the Consensus Conference suggest that other methods may be more reliable. The use of "other reliable formula" is too vague and ill-defined, and appears to allow any formula to be used to calculate renal function. This would defeat the whole purpose of having uniform listing criteria.

I would now like to discuss areas of basic science research in transplantation that deserve your attention.

We recommend that a task force (made up of experts knowledgeable in the measurement of renal function) be established to develop and test a formula that uses serum creatinine and other easily measured parameters to estimate glomerular filtration rate. This could be done relatively quickly, using existing data. However, if it is felt that listing criteria should be established immediately, then we recommend that the formula devised and tested by Dr. Andrew Levey, using data from the Modification of Diet in Renal Disease Study, be used until additional analysis suggests appropriate modifications.

Finally, we feel that the level of renal function, i.e., corresponding to a creatinine clearance less than 20 ml/min is too high. Instead, we recommend that the minimal acceptable level be less than 18 ml/min.

The American Society of Transplant Physicians supports UNOS in this important effort to establish uniform listing criteria for renal transplantation. We are ready to assist UNOS in any way in this endeavor.