The impact of macro‐ and micro‐steatosis on the outcomes of patients who undergo liver transplant: Analysis of the UNOS‐STAR database

Abstract Background and Aims The presence of steatosis in a donor liver and its relation to post‐transplantation outcomes are not well defined. This study evaluates the effect of the presence and severity of micro‐ and macro‐steatosis of a donor graft on post‐transplantation outcomes. Methods The UNOS‐STAR registry (2005–2019) was used to select patients who received a liver transplant graft with hepatic steatosis. The study cohort was stratified by the presence of macro‐ or micro‐vesicular steatosis, and further stratified by histologic grade of steatosis. The primary endpoints of all‐cause mortality and graft failure were compared using sequential Cox regression analysis. Analysis of specific causes of mortality was further performed. Results There were 9184 with no macro‐steatosis (control), 150 with grade 3 macro‐steatosis, 822 with grade 2 macro‐steatosis and 12 585 with grade 1 macro‐steatosis. There were 10 320 without micro‐steatosis (control), 478 with grade 3 micro‐steatosis, 1539 with grade 2 micro‐steatosis and 10 404 with grade 1 micro‐steatosis. There was no significant difference in all‐cause mortality or graft failure among recipients who received a donor organ with any evidence of macro‐ or micro‐steatosis, compared to those receiving non‐steatotic grafts. There was increased mortality due to cardiac arrest among recipients of a grade 2 macro‐steatosis donor organ. Conclusion This study shows no significant difference in all‐cause mortality or graft failure among recipients who received a donor liver with any degree of micro‐ or macro‐steatosis. Further analysis identified increased mortality due to specific aetiologies among recipients receiving donor organs with varying grades of macro‐ and micro‐steatosis.