SAN FRANCISCO – The type of liver graft used in transplantation plays a large role in early development of new-onset diabetes, according to a retrospective study of 430 patients from the United Kingdom.
A team led by Dr. Hermien Hartog, an honorary clinical fellow in the Liver Unit, Queen Elizabeth Hospital, Birmingham, England, studied patients undergoing primary liver transplant between 2008 and 2012. Patients were excluded from the study if they had preexisting diabetes, had died, or had undergone retransplantation within 90 days.
Dr. Hermien Hartog
The investigators assessed both the development of new-onset diabetes after transplant (NODAT), using criteria adapted from a published article (Transplantation 2013;96:58-64), and its resolution, defined as the date of cessation of antihyperglycemic therapy or the last episode of hyperglycemia.
Seventy-nine percent of the patients received grafts donated after brain death (DBD), Dr. Hartog reported at the annual meeting of the 2014 World Transplant Congress. Among the recipients of grafts donated after circulatory death (DCD), the mean warm ischemic time was 21 minutes.
With a median follow-up of 2.5 years, the cumulative 1-year incidence of NODAT was 19% in the entire cohort, with a median time to onset of 30 days. In the 44% of affected patients whose NODAT resolved, the median time to resolution was 150 days post transplantation, Dr. Hartog reported at the congress, which was sponsored by the American Society of Transplant Surgeons.
The cumulative 1-year incidence of NODAT was 23% in DCD graft recipients and 18% in DBD graft recipients, a nonsignificant difference. But when patients were stratified by graft type, "we saw an early occurrence and high peak incidence of NODAT in DCD graft recipients. Also, a larger proportion of these patients resolved their NODAT over time," she commented.
The overall temporal pattern suggested that "the effect that we see of graft type seems to be temporary and [lessens] over time when multifactorial factors come into play," according to Dr. Hartog.
In multivariate analyses, the risk of NODAT within 90 days of transplantation was higher for patients who received a DCD graft (hazard ratio, 1.8). More detailed analysis showed that the elevation of risk was greatest within the first 15 days.
"Our study confirms known associations with NODAT after liver transplantation but identifies DCD graft as a novel risk factor. This causes a temporary effect in the early post-transplant period that is independent from known risk factors," Dr. Hartog commented.
"Based on our observations, we hypothesize that hyperglycemia may be related to liver graft function through ischemia-reperfusion–induced hepatic insulin resistance," she added. "We are currently trying to confirm our data in an independent data set, which will also include postreperfusion glucose levels and correlation with the insulin receptor pathway in time-zero liver biopsies."
"The clinical relevance of our findings is as yet unknown," she acknowledged. However, they may help inform new approaches for graft optimization and selection.
Session cochair Dr. Darius Mirza, also of the University of Birmingham, asked, "Why does the pattern of recovery seem to be different in the DCDs versus the DBDs? Also, why are the cumulative incidence and the time frame so different?"
"Actually, in the literature, I have not seen any reports looking at the early post-transplant period. So most reports look at one time point, normally 1 year," Dr. Hartog replied. "What I think is that there is an early peak caused by DCD grafts that would explain why there is an early peak, but also why those patients recover later on. I think this peak is a bit obscure because there are also other factors that come into play, maybe after a while, that will obscure that first peak. If you would take those other factors out of the equation, I think you would just see a peak in the early period."
Dr. Mirza also wondered about the role of using DCD grafts that are accepted under extended criteria. "So you start off using mainly young, fit DCD livers. Now, the vast majority are extended-criteria DCD livers. Do you think that plays a role, or is it too early to say?"
"Yes, I think so," Dr. Hartog said, while adding that this phenomenon is likely not restricted to DCD grafts. "From earlier literature, there is a clear difference between a living donated graft and deceased donation. And it might also be that the extended grafts or the more steatotic grafts may exhibit this effect more than the better grafts."
Dr. Hartog disclosed no conflicts of interest relevant to the research.