Twenty-Year Comparative Analysis of Patients With Autoimmune Liver Diseases on Transplant Waitlists

Abstract

Background & aims: The rarity of autoimmune liver disease poses challenges to epidemiology studies. However, waitlists for liver transplantation can be used to study patients with end-stage liver diseases. We used these waitlists to assess trends in numbers and demographics of patients awaiting liver transplant for primary biliary cholangitis (PBC), primary sclerosing cholangitis (PSC), or autoimmune hepatitis (AIH).

Methods: We collected data from UK and US national registries for all adults on liver transplant waitlists, from January 1, 1995, through December 31, 2014. We analyzed data from patients with PBC (n = 1434 in the United Kingdom and n = 5598 in the United States), PSC (n = 1093 in the United Kingdom and n = 6820 in the United States), and AIH (n = 538 in the United Kingdom and n = 4949 in the United States). Numbers of listings per year were adjusted to the estimated populations during each year. Regression analyses were used to examine trends and comparative statistics were used to evaluate differences in individual characteristics among groups.

Results: Over the total study period, listings for PBC were 1.2 and 1.0 per million population per year in the United Kingdom and United States, respectively; for PSC, 0.9 and 1.2 per million population per year; and for AIH, 0.5 and 0.8 per million population per year. Over the period studied, numbers of listings for PBC decreased by 50% in both countries; changes in numbers of listings for PSC and AIH were smaller and not consistent between countries. By 2014, PSC had become the leading indication for liver transplantation among patients with autoimmune liver diseases in both countries. Median patient ages at time of listing were lower than those reported as median age of diagnosis for AIH and PBC. The ratio of women:men with PBC decreased by almost 50% from 1995 through 2014. Men with PSC were placed on the waitlist with higher disease severity scores than women in both countries. Among patients with PBC, those of black race were under-represented on waitlists from both countries. Among patients with PSC, Hispanics were under-represented on waitlists in the United States. Patients of non-white races were placed on waitlists at younger ages for all diseases; age differences in waitlist placement varied by up to 10 years, depending on race, among patients with PBC.

Conclusions: In an analysis of data collected from UK and US national liver transplant registries over 20 years, we found that PSC has become the leading indication for liver transplantation among patients with autoimmune liver diseases. Numbers of patients with PBC placed on waitlists, and the ratio of women:men with PBC, each decreased by almost 50%, possibly due to increased treatment with ursodeoxycholic acid. Within groups of patients on the transplant waitlist for PBC, PSC, or AIH, we found differences in age, sex, disease severity scores, and ethnicity between diseases and countries that require further study.

Keywords: Autoimmune Hepatitis; Autoimmunity; Epidemiology; Incidence; Liver Transplantation; NHSBT; Population Study; Primary Biliary Cholangitis; Primary Sclerosing Cholangitis; UNOS.