THE UNOS CREG STUDY MAY ADVERSELY AFFECT ORGAN ALLOCATION.
PJ Wetzsteon, P Sharpe, and DJ Norman, Oregon Health Sciences University, Portland, OR.
UNOS is conducting a randomized, prospective study to determine the value of CREG matching in kidney allocation and outcomes. Cadaver donor kidneys are alternately allocated to recipients via a CREG point system (CPS) or the standard UNOS point system (SPS). The CPS assigns 10 points for a 0 CREG / 0 DR mismatch (MM) and no points for lesser matches. The SPS assigns 7, 5 & 2 points for 0 BDR, 1 BDR and 2BDR MM respectively.
Before the study began, we were concerned that most kidneys randomized into the CPS would be allocated on a time-waiting basis only and recipients with better matches would not be allowed to receive those kidneys. Our data, shown below, have confirmed our concerns.
To determine if patients with better matches were overlooked when a donor was randomized to allocation via CPS, an identical dummy donor (DD) was entered into the UNOS computer and the SPS was used to generate a priority list from the same patient database. Conversely, if the donor was randomized to SPS allocation, a DD was entered and run via the CPS. The BDR MM for the highest ranking XM negative patient determined by the randomized donor run (either CPS or SPS) was compared to highest ranking XM negative patient determined by the dummy run.
For the 10 kidneys (9 donors) randomized to the CPS, there were no patients identified with 0 CREG / 0 DR MM, and the highest ranking patient was determined by waiting time only. In 5 instances the kidney would have been assigned to a patient with fewer BDR MM had the SPS been used. For the 19 kidneys (16 donors) randomized to SPS there were 10 patients who received BDR MM points. In 8 instances the CPS would have allocated kidneys to patients with more BDR MM, and no patients with 0 CREG / 0 DR MM would have been identified. Among the entire group of 29 kidneys, 52% of the patients had a < 2 BDR MM when randomized by SPS versus only 17% by CPS (p< 0.006).
The UNOS study should be redesigned so that the CPS includes the same points given for BDR MM as in the SPS. Subsequently, when no patient with a 0 CREG / 0 DR MM is identified (small waiting lists are at risk for this) patients with fewer BDR MM will not be passed over.