Since 2004, there’s been almost a tripling of the number of nonalcoholic steatohepatitis patients waiting for liver transplants; the condition is now the second leading reason to be put on the waiting list in the United States, according a study published online in Gastroenterology.
Even so and for reasons that are not fully clear, adults with nonalcoholic steatohepatitis (NASH) are less likely to survive for 90 days on the wait list than are patients with alcoholic liver disease (ALD), and less likely to get a new liver within 90 days than are patients with ALD, hepatitis C virus (HCV), or a blend of both. For now, HCV remains the No. 1 reason for liver transplants in the United States (Gastroenterology 2014 Nov. 24 [doi: 10.1053/j.gastro.2014.11.039]).
“Our study provides valuable information about the changing epidemiology of chronic liver disease among wait-listed patients, and adds greatly to our understanding of the epidemiology of NASH in the United States,” the researchers wrote. The rapid rise in the prevalence of NASH is “a direct consequence of the worldwide obesity epidemic” as well as greater awareness of the condition. An expected decline in HCV-related cirrhosis due to effective antiviral therapy “will further contribute to the changing epidemiology of patients awaiting liver transplants in the United States,” said the authors, led by Dr. Robert Wong of the division of gastroenterology and hepatology at Highland Hospital, Oakland, Calif.
“Given the expected continued rise in the number of NASH patients awaiting liver transplant, additional research is needed to improve wait-list survival and … outcomes among this cohort. In addition, the projection that overall donor availability will significantly diminish in the next 15-20 years emphasizes the need for additional research to improve liver transplant opportunities for NASH patients, including the option of living donor[s],” they said.
The researchers analyzed data from the United Network for Organ Sharing and Organ Procurement and Transplantation Network registry.
From 2004 to 2013, new wait-list registrants with NASH increased by 170% from 804 to 2,174; those with ALD increased by 45% from 1,400 to 2,024; and those with HCV increased by 14% from 2,887 to 3,291. Registrants with both HCV and ALD decreased by 9% from 880 to 803. NASH became the second-leading disease among liver transplant wait-list registrants in 2013.
Patients with ALD had a significantly higher Model for End-Stage Liver Disease (MELD) score at the time of registration than did others. However, after adjustment for MELD and other variables, patients with ALD were less likely to die within 90 days than were NASH patients (OR 0.77; 95% CI 0.67–0.89; P < .001). No difference was seen in wait-list mortality between NASH and HCV and HCV/ALD patients.
Compared with NASH, patients with HCV (OR 1.45; 95% CI 1.35–1.55; P < .001), ALD (OR 1.15; 95% CI: 1.06–1.24; P < .001), and HCV/ALD (OR 1.29; 95% CI 1.18–1.42; P < .001) were all significantly more likely to receive a liver after 3 months on the wait list.
A “potential explanation for these observations might be etiology-specific differences in disease progression, such that more aggressive etiologies (e.g., HCV or HCV/ALD) can have a more rapid rise in MELD score, receive liver transplant, and have lower wait-list mortality, and etiologies with less rapid progression (e.g., NASH) can have slower rise in MELD score over time, lower rates of LT, but no significant increase in wait-list mortality,” the investigators said.
Overall 1-year wait-list survival among NASH patients decreased from 42.8% in 2004-2008 to 25.6% in 2009-2013, and overall 1-year probability of receiving liver transplant among NASH patients also decreased from 42.1% in 2004-2008 to 39.6% in 2009-2013. The trends were similar for other etiologies, perhaps in part because there are more people waiting for a liver.
The authors said they have no financial conflicts to disclose.