Living Donors

The OPTN database of the United Network for Organ Sharing (UNOS) was used to identify patients registered on the waiting list on or before April 24, 2006, during 2 periods, pre-MELD (January 1, 1996–December 31, 2000) and post-MELD (February 28, 2002–March 31, 2006). The study population comprised all non-Hispanic black and non-Hispanic white patients aged 18 years or older who were liver transplant waiting list registrants during those periods. Race is identified by patients when registering on the UNOS waiting list. Hispanics were not included as the UNOS database has multiple variables that identify race and ethnicity with often discordant results.
Patients listed for retransplantation or multiorgan transplantation were excluded. Given the different criteria for organ allocation, patients were excluded if they were listed as status 1, defined as fulminant liver failure with a life expectancy without liver transplantation of less than 7 days. We also excluded patients listed as temporarily inactive because they could not be properly assessed for receipt of liver transplantation. The UNOS variables collected included listing date, age, sex, blood type, listing diagnoses, race, education level, insurance payer, UNOS region, calculated MELD score at listing and removal, waiting time, reason for removal from the waiting list, and comorbid illnesses. Waiting time was determined using the first date each patient was placed on the waiting list and the date of removal from the list.
Education level was grouped into 3 categories comprising no education or grade school education, high school and attended college without degree, and college degree or higher. The UNOS regions were grouped into 4 categories according to region of the country (northeast = UNOS regions 1, 2, and 9; southeast = UNOS regions 3, 4, and 11; midwest = UNOS regions 7, 8, and 10; and west = UNOS regions 5 and 6). Listing diagnoses were grouped into 11 common diagnostic categories including cryptogenic cirrhosis, hepatitis C virus, hepatitis B virus, Laennec cirrhosis, nonalcoholic steatohepatitis, autoimmune hepatitis, primary biliary cirrhosis, primary sclerosing cholangitis, alpha-1 antitrypsin deficiency, hemochromatosis, and HCC. All other diagnoses were combined into a category designated “other.”
Patients with reasons for removal from the waiting list, such as emergency transplant, died during transplant, and transplanted at another center, were combined into a category called “transplanted.” Similarly, patients removed from the waiting list with reasons such as medically unsuitable or too sick for liver transplantation were combined into a category called “too sick for liver transplantation,” and patients whose reasons for removal from the waiting list were identified as refused transplant, transferred to another center, other, condition improved, living donor, and removed in error were combined into a category called “other.” Patients who died before liver transplantation were kept as 1 category and called “died.”