Association Between Survival After Living Donor Liver Transplantation and Recipient Systemic Inflammation and Body Composition

<b>Background/Objectives:</b> Preoperative sarcopenia in liver transplantation (LT) recipients is an important prognostic factor of LT outcomes. Systemic inflammatory status (SIS) has been proposed as a unifying mechanism for skeletal muscle loss; thus, considering SIS and sarcopenia together may enhance prognosis assessment in patients undergoing LT. Herein, we aimed to describe the relationship between the SIS and skeletal muscle index (SMI) with short-term and long-term mortality post-living donor LT (LDLT). <b>Methods:</b> In total, 3387 consecutive adult LDLT recipients were retrospectively evaluated. The neutrophil-to-lymphocyte ratio (NLR, using a cut-off of 3) was utilized as an SIS. SMI was calculated using computed tomography scans, measured at the third lumbar vertebra; sex-specific cut-offs were determined from contemporary donors. Univariate and multivariable Cox proportional hazard analyses were performed. <b>Results:</b> Decreasing SMI was associated with increasing NLR. Increasing NLR and decreasing SMI both showed dose-dependent relationships with a risk of 90-day mortality. Within sarcopenic patients, NLR > 3 (vs. NLR ≤ 3) was associated with higher 90-day (9.3% vs. 3.5%, <i>p</i> = 0.049) and overall mortality (28.4% vs. 19.1%, <i>p</i> = 0.045). Sarcopenia and NLR > 3 (vs. neither) were independent predictors of 90-day mortality (hazard ratio [HR] 2.48 [1.40-4.40], <i>p</i> = 0.002) and overall mortality (HR, 1.81 [1.37-2.38], <i>p</i> < 0.001) after multivariable adjustment. When stratified by age, sex, and MELD score, the association between sarcopenia and overall mortality persisted in all subgroups, with the highest risk observed in women (HR 3.43, 95% CI 1.83-6.43). <b>Conclusions:</b> Sarcopenia, with the systemic inflammatory response, nearly doubled the risk of 90-day and overall mortality post-LT, proposing that these readily available biomarkers are a practical index for predicting survival post-LT. Considering that these are potentially modifiable factors, our result may provide a new therapeutic target to improve survival post-LT.