New research suggests a better monitoring system might be warranted for fatty liver diseases including non-alcoholic fatty liver disease (NAFLD) for living donors.¹

A team led by Ryoichi Goto, Department of Gastroenterological Surgery I, Hokkaido University Graduate School of Medicine, evaluated the safety of living donors, particularly for outcomes from liver postdonation hepatectomies.

“Approximately 30 years have passed since the first experience of living donor liver transplantation (in Japan),” the authors wrote. “The time to evaluate the long-term safety of living donors has been fulfilled.”

However, the rate of NAFLD is increasing worldwide and there is very limited data on the long-term outcomes of living donors.

In the study, the investigators evaluated 212 living donors between 1997-2018 using computed tomography at >1-year postdonation. The team defined fatty liver as a liver to spleen ratio of greater than 1.1 within 6 months prior to the donation hepatectomy. This was confirmed using intraoperative pathological diagnosis of a macrovascular steatosis less than 5% of hepatocytes.

The investigators scheduled follow-ups for living donors at 1, 3, and 12 months after donation and annually until at least 5 years postdonation.

Each participant must be a blood relative within the second degree or spouse of the recipient, not have physical and mental illness, ABO-identical or compatible, aged 20-65 years, and volunteered freely with an understanding of the risks and benefits.

The team also identified predictive risk factors for the development of a fatty liver that were evaluated for several parameters, including sex, height, age, weight, body mass index (BMI), history of diet-exercise, daily alcohol consumption, donation surgery, ratio of graft volume relative to standard liver

The results show, 14.2% (n = 30) of participants had fatty liver at 4.2 years postdonation with cumulative incidence rates of fatty liver of 3.1%, 12.1%, 22.1%, and 27.7% at 2, 5, 10, and 15 years postdonation, respectively.

For the patients who developed fatty liver, 60% (n = 18) displeased a severe steatosis (liver to spleen ratio, <0.9). Moreover, 16.7% (n = 5) of the patients had a prior history of excessive alcohol abuse and more than 30% of the participants developed a metabolic syndrome such as obesity, hyperlipemia, or diabetes.

While 20% (n = 6) had a Fib-4 index greater than 1.3, including 1 case of a Fib-4 index greater than 2.67, the investigators did not identify a significant increase in Fib-4 index in patients with fatty liver compared to those who did not develop fatty liver (P = 0.66).

The investigators also identified several risk factors associated with the risk of developing fatty liver, including the male sex, pediatric recipients, and higher body mass index (BMI) at donation.

“Living donors with risk factors for developing fatty liver should be carefully followed-up for the prevention and management of metabolic syndrome,” the authors wrote.

References

Goto R, Kawamura N, Watanabe M, et al. Long‐term risk of a fatty liver in liver donors. Annals of Gastroenterological Surgery. 2023. doi:10.1002/ags3.12658