Obesity is a risk factor for progression to kidney transplant waitlisting after liver transplantation

Temporal changes in obesity and outcomes for patients listed for liver transplant

BACKGROUND

The prevalence of obesity has dramatically increased. Candidates with obesity have higher waitlist mortality and are less likely to undergo liver transplantation (LT). The association of obesity with post-transplant mortality is inconsistent.

METHODS

This study quantified the temporal trends in waitlist and transplant outcomes among patients with obesity using 2013-2023 SRTR data. Obesity class was defined as follows: no obesity (body mass index [BMI] of 18.5-29.0 kg/m2), class I obesity (BMI of 30.0-34.0 kg/m2), class II obesity (BMI of 35.0-39.0 kg/m2), and class III obesity (BMI of 40.0-55.0 kg/m2). The risks of waitlist and post-transplant mortality were quantified using adjusted competing risks and Cox proportional hazards.

RESULTS

Among 103,640 candidates and 58,692 recipients, candidates with higher obesity classes had higher listing Model for End-Stage Liver Disease (MELD) scores that increased over time. Candidates with class III obesity were listed and transplanted at higher MELD scores than those without obesity, those with class I obesity, and those with II obesity. Nearly 40% of candidates with class III obesity had listing MELD scores of ≥30. From 2013-2017 to 2018-2023, the waitlist mortality decreased by 35% in candidates with class III obesity (subhazard ratio, 0.65 [95% CI, 0.58-0.73]; P <.001), and post-transplant mortality decreased by 20% for recipients with class III obesity (hazard ratio, 0.80 [95% CI, 0.66-0.96]; P =.02). However, over time, post-transplant mortality differed by obesity class, with no reduction in post-transplant mortality among recipients with class I or II obesity.

CONCLUSION

LT candidates and recipients with class III obesity are being listed and transplanted at higher MELD scores with improvement in outcomes over time. Despite the higher risk, temporal trends in LT outcomes for this population are favorable. Given the higher disease severity at listing for candidates with class III obesity, referral patterns for LT evaluation in these patients should be evaluated.

Intraoperative hypotension during critical phases of liver transplantation and its impact on acute kidney injury: a retrospective cohort study

INTRODUCTION

Acute Kidney Injury (AKI) following Liver Transplantation (LT) is associated with prolonged ICU and hospital stay, increased risk of chronic renal disease, and decreased graft survival. Intraoperative hypotension is a modifiable risk factor associated with postoperative AKI. We aimed to determine in which phase of LT hypotension has the strongest association with AKI: the anhepatic or neohepatic phase.

METHODS

This retrospective cohort study included adult patients undergoing LT between January 2010 and June 2022. Exclusion criteria were re-do or combined transplantations, preoperative dialysis, and early graft failure or death. Primary outcome was AKI as defined by KDIGO. Hypotension was Mean Arterial Pressure (MAP) below predefined thresholds in minutes. Risk adjusted logistic regression analysis considered hypotension in 3 periods: the total procedure, anhepatic phase, and neohepatic phase.

RESULTS

Our cohort included 1153 patients. The median MELD-NA score was 19 (IQR 11-28), and 412 (35.9%) were living-related donations. AKI occurred in 544 patients (47.2%). The unadjusted model showed an association with AKI for MAP < 60 mmHg (OR = 1.011 [1.0, 1.022], p = 0.047) and MAP < 55 mmHg (OR = 1.023 [1.002, 1.047], p = 0.040) in the anhepatic phase, and for MAP < 60 mmHg (OR = 1.032 [1.01, 1.056], p = 0.006) in the neohepatic phase. The adjusted model did not reach significance in the subgroups but did in the total procedure: MAP < 60 mmHg (OR = 1.005 [1.002, 1.008], p < 0.001) and MAP < 55 mmHg (OR = 1.008 [1.003-1.013], p = 0.004).

CONCLUSION

Intraoperative hypotension is independently associated with AKI following LT. This association is seen during the anhepatic phase. Maintaining MAP above 60 mmHg may improve kidney function after LT.

Results of a multidisciplinary strategy to improve the management of cardiovascular risk factors after liver transplantation

Although liver transplantation (LT) recipients are at high cardiovascular risk (CVR), the management of CVR factors (CVRF) after LT is far from optimal and needs to be improved. For this reason, we developed a multidisciplinary protocol to standardize the identification, risk stratification, management, and targets of therapy of CVRF during the first post-LT year. The grade of identification and control of CVRF 12 months after LT in the postintervention cohort (LT January 2018-January 2020, n = 150) were compared with a control cohort who underwent LT between July 2015 and December 2016 (n = 100). Before LT, the prevalence of metabolic-associated fatty liver disease as the indication of LT and the presence of obesity were significantly higher in the postintervention cohort, whereas the prevalence of other CVRF and renal dysfunction tended to be higher. Cyclosporine A was used less frequently in the postintervention cohort, whereas everolimus tended to increase. At 12 months after LT, the proportion of patients with measured blood pressure (88% vs. 56%), glycosilated hemoglobin (HbA1c; 96% vs. 72%), and high-density lipoprotein/low-density lipoprotein cholesterol (67% vs. 33%) was higher in the postintervention than in the control cohort (all p < 0.001). Blood pressure (64% vs. 36%, p = 0.02) and HbA1c (85% vs. 70%, p = 0.1) were within target in more individuals with hypertension and diabetes mellitus, respectively, in the postintervention cohort. Median total cholesterol levels were lower in the postintervention (184 mg/dl; interquartile range [IQR], 160-210 mg/dl) than in the control cohort (212 mg/dl; IQR, 186-240 mg/dl; p = 0.02). At 2 years after LT, the incidence of cardiovascular events was 14% in the control cohort and 6% in the postintervention cohort (p = 0.063). In conclusion, a multidisciplinary, multiprofessional strategy can achieve a higher grade of assessment and management of post-LT CVR despite a worsening metabolic profile of LT recipients.

Divergent trajectories of lean vs obese non-alcoholic steatohepatitis patients from listing to post-transplant: A retrospective cohort study

BACKGROUND

Non-alcoholic steatohepatitis (NASH) cirrhosis is the second most common indication for liver transplantation (LT). The role of body mass index (BMI) on outcomes of NASH cirrhosis has been conflicting.

AIM

To compare the longitudinal trajectories of patients with lean vs obese NASH cirrhosis, from listing up to post-transplant, having adjusted their BMI for ascites.

METHODS

We retrospectively reviewed all adult NASH patients listed for LT in our program from 2012 to 2019. Fine-Gray Competing Risk analyses and Cox Proportional-Hazard Models were performed to examine the cumulative incidence of transplant and survival outcomes respectively.

RESULTS

Out of 265 NASH cirrhosis listed patients, 176 were included. Median age was 61.0 years; 46% were females. 111 patients underwent LT. Obese robust patients had better waitlist survival [hazard ratio (HR): 0.12; 95%CI: 0.05–0.29, P < 0.0001] with higher instantaneous rate of transplant (HR: 5.71; 95%CI: 1.26–25.9, P = 0.02). Lean NASH patients had a substantially higher risk of graft loss within 90 d post-LT (1.2% vs 13.8%, P = 0.032) and death post-LT (2.4% vs 17.2%, P = 0.029). 1- 3- and 5-year graft survival was poor for lean NASH (78.6%, 77.3% and 41.7% vs 98.6%, 96% and 85% respectively). Overall patient survival post-LT was significantly worse in lean NASH (HR: 0.17; 95%CI: 0.03–0.86, P = 0.0142) with 83% lower instantaneous rate of death in obese group.

CONCLUSION

Although lean NASH is considered to be more benign than obese NASH, our study suggests a paradoxical correlation of lean NASH with waitlist outcomes, and graft and patient survival post-LT.