Background: Few studies have evaluated the accuracy of United Network for Organ Sharing (UNOS) or Scientific Registry of Transplant Recipients data among patients listed for liver transplantation. Of particular importance for transplant policy and practice is whether patients' outcomes are coded properly.
Methods: Using data from four transplant centers, we identified all liver transplant candidates removed from the waitlist from February 27, 2002 to July 24, 2010, with a specific focus the removal code of "other."
Results: Among nontransplanted patients at these centers, 2206 patients were removed for death or clinical deterioration. Of these, 8.6% (189 of 2206) were misclassified; they were assigned the UNOS removal code of "other." Among these 189 misclassified patients, 128 became medically unsuitable, 35 died, and 26 became too sick to transplant. Nearly one-half (46.8%) of misclassified patients were removed due to advanced hepatocellular carcinoma. Among true waitlist removals for death, only 35 of 1593 (2.2%) were misclassified. Conversely, of true removals for clinical deterioration, 154 of 612 (25.2%) were misclassified, with significant (P < 0.001) center variation: 4.4% (Baylor), 8.0% (Georgetown), 32.6% (University of Pennsylvania), and 45.0% (Mount Sinai). Extrapolating these data to the entire United States, if "other" patients who truly died or clinically deteriorated were recoded appropriately, there would be an additional 2525 (95% confidence interval, 2046-3102) patients removed from the waitlist due to death (331) or clinical deterioration (2194) since 2002.
Discussion: A substantial proportion of patients truly removed from the waitlist for death or clinical deterioration were misclassified as "other." Thus, analyses using the UNOS or the Scientific Registry of Transplant Recipients database may underestimate the true proportion of patients removed from the waitlist for clinical deterioration.