Referring physicians are poor predictors of patient mortality
The United Network for Organ Sharing (UNOS) currently utilizes scores based on the Model for End-Stage Liver Disease (MELD) or Pediatric End-Stage Liver Disease (PELD) to prioritize patients waiting for liver transplants. The MPS (MELD/PELD score) is a well-validated measure of short-term mortality from liver disease, however, referring physicians who believe a patient faces a greater mortality risk than predicted by the MPS can request accelerated listing.
Regional review boards can approve or deny these requests, and a new study published in the May 2004 issue of Liver Transplantation – the official journal of the American Association for the Study of Liver Diseases (AASLD) and the International Liver Transplantation Society (ILTS) – shows that these boards fairly and accurately distinguish between high and low risk patients. Their denials of physicians' requests for accelerated listings do not increase mortality for those patients. Liver Transplantation is published on behalf of the societies by John Wiley & Sons, Inc., and is available online via Wiley InterScience at http://www.interscience.wiley.com/journal/livertransplantation.
To determine the effect of regional review board decisions on the mortality of physician-referred patients, researchers led by Michael D. Voigt of the University of Iowa, analyzed 1,965 nationwide referrals to UNOS regional review boards. They noted which cases were approved and which were denied, and gathered information about patient deaths while awaiting transplantation. They found that there was no significant difference in survival to transplantation whether accelerated listing was approved or denied for adult or pediatric cases.
Secondly, the researchers examined whether or not referring physicians predicted death better than the MPS. They found that the physicians had poor predictive capacity and added no additional information to the risk assessment of the true MPS.
"The absence of increased death in denied cases and the poor ability of referring physicians to predict outcome – but the excellent predictive capacity of the MPS – should reassure UNOS, referring physicians, patients, and the transplant community that patients are being treated fairly," the authors report. "Taken together, these observations show that regional review boards function well not only in separating high- from low-risk patients referred to them, but also that the process contributes additional prognostic information, which fine-tunes organ allocation."
The study was limited by a lack of analysis of post-transplant survival – which might have shown a deleterious effect of delayed transplantation in denied cases, and also by the small numbers of patients in the pediatric, pulmonary, and metabolic/structural groups.
Still, the findings confirm the accuracy of the MELD-PELD score, while affirming the role of the regional review boards. Further, they indicate that the UNOS allocation policy makes appropriate provisions for the sickest patients.
And though the data showed that referring physicians did not predict mortality accurately, the researchers suggested that these physicians be aware of a tendency to request only small increases in MPS for their sickest patients, while requesting larger increases in patients with lower MPS. "This may be associated with a worse outcome for the sicker patients receiving the small increases in score," the authors conclude.
Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009
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