Liver Transplant Candidates With Obesity and High MELD Are Not at Increased Risk for Post Transplant Death or Graft Failure.

Abstract

The prevalence of obesity is increasing among patients undergoing liver transplant (LT). It has been proposed that an elevated BMI in the setting of higher MELD scores may confer increased risk for poor post-LT outcomes. Aims: To investigate the impact of BMI on post-LT outcomes in the context of pre-LT liver disease severity as assessed by MELD score. Methods: We identified all adult (≥18 yrs) primary LT recipients from 3/1/02-9/30/11 in the UNOS dataset. BMI was categorized as: underweight, normal, overweight, Obese Class I, II, or III (<18.5; 18.5-24.9; 25-29.9; 30-34.9; 35-39.9; ≥40 kg/m2, respectively). 1-year post-LT death and graft loss were modeled using Cox regression and included an interaction term between BMI category and MELD. Results: Of the 45551 LT recipients identified, 68% were male, median [IQR] age=55 [49-60] yrs, MELD=19 [13-26], DRI=1.39 [1.12-1.69] and BMI categories were: Underweight (n=863, 1.9%), Normal (n=13262, 29%), Overweight (n=16329, 36%), Obese Class I (n=9639, 21%), Class II (n=4062, 9%), and Class III (n=1396, 3%). In adjusted multivariate analyses, increasing BMI was not associated with increased risk for post-LT death or graft loss at 1-yr. There were statistically significant interactions between BMI and MELD with respect to risk for 1-yr post-LT death (p=0.02) and graft loss (p=0.01) in the underweight BMI category only. Obesity (Class I, II, or III) was not associated with increased risk for 1-yr death or graft loss, regardless of MELD. However, there was increased risk for death (Figure 1) and graft loss (trend similar to patient death, data not shown) at 1-yr post-LT in patients with very low BMI (<18.5 kg/m2) who were transplanted at lower MELD scores. Conclusions: Obese LT recipients do not have increased risk of death or graft loss post-LT, even in the setting of higher MELD scores. LT recipients with the lowest BMIs (<18.5 kg/m2) are at increased risk for death and graft loss at lower MELD scores, with the specific mechanisms underlying this phenomenon requiring further investigation.Figure: No Caption available.