“Weighing the risk”: Obesity and outcomes following liver transplantation

The impact of race and comorbid conditions on adult liver transplant outcomes in obese recipients

Many prior studies comparing liver transplant outcomes between obese and nonobese recipients found no significant differences in survival. However, obesity is intrinsically associated with demographic factors such as race and comorbidities. Thus, this work aimed to analyze the effects of obesity, in conjunction with these factors, on liver transplant outcomes. OPTN data was analyzed to identify adult-only, first-time liver transplants between 1995 and 2019. Obesity was defined by the CDC obesity classification. Race, insurance status, age, and comorbidities were analyzed together with patient survival and graft survival using a multivariable Cox Proportional-Hazards model and long-term survival with Kaplan-Meier curves. The multivariable models found that being black, older than 50 years, having diabetes, or having nonprivate insurance were all risk factors for both patient survival and graft survival after liver transplant. Adjusting for obesity class, black recipients had a 20% lower patient survival and 23% lower graft survival compared with nonblack recipients. Survival curves verified that obese black liver transplant recipients had poorer long-term patient survival and graft survival compared with both obese nonblack and nonobese recipients. In conclusion, obesity compounds known factors associated with poor outcomes after liver transplantation. Further work is critical to understand why these discrepancies persist.

Impact of Morbid Obesity on Liver Transplant Candidacy and Outcomes: National and Regional Trends

BACKGROUND

Body mass index (BMI) limits for liver transplant (LT) candidacy are controversial. In this study, we evaluate waitlist and post-LT outcomes, and prognostic factors and examine regional patterns of LT waitlist registration in patients with BMI ≥40 versus BMI 18-39.

METHODS

United Network for Organ Sharing (UNOS) data were analyzed to assess waitlist dropout, post-LT survival, and prognostic factors for patient survival. The distribution of waitlisted patients with BMI ≥40 was compared with the Centers for Disease Control Behavioral Risk Factors Surveillance System data to explore the rates of morbid obesity in the general population of each UNOS region.

RESULTS

Post-LT outcomes demonstrate a small but significantly lower 1- and 3-y overall survival for patients with BMI ≥45. Risk factors for post-LT mortality for patients with BMI ≥40 included age >60 y, prior surgery, and diabetes on multivariable analysis. Model for End-Stage Liver Disease >30 was significant on univariable analysis only, likely due to the limited number of patients with BMI ≥40; however, median Model for End-Stage Liver Disease scores in this BMI group were higher than those in patients with lower BMI across all UNOS regions. Patients with BMI ≥40 had a higher waitlist dropout in 4 regions. Comparison with BRFSS data illustrated that the proportion of waitlisted patients with BMI ≥40 was significantly lower than the observed rates of morbid obesity in the general population in 3 regions.

CONCLUSIONS

While BMI ≥45 is associated with modestly lower patient survival, careful selection may equalize these numbers.

Improving Outcomes of Bariatric Surgery in Patients With Cirrhosis in the United States: A Nationwide Assessment

INTRODUCTION

With increasing burden of obesity and liver disease in the United States, a better understanding of bariatric surgery in context of cirrhosis is needed. We described trends of hospital-based outcomes of bariatric surgery among cirrhotics and determined effect of volume status and type of surgery on these outcomes.

METHODS

In this population-based study, admissions for bariatric surgery were extracted from the National Inpatient Sample using International Classification of Diseases, 9th and 10th Revision, Clinical Modification codes from 2004 to 2016 and grouped by cirrhosis status, type of bariatric surgery, and center volume. In-hospital mortality, complications, and their trends were compared between these groups using weighted counts, odds ratios [ORs], and logistic regression.

RESULTS

Among 1,679,828 admissions for bariatric surgery, 9,802 (0.58%) had cirrhosis. Cirrhosis admissions were more likely to be in white men, had higher Elixhauser Index, and higher in-hospital complications rates including death (1.81% vs 0.17%), acute kidney injury (4.5% vs 1.2%), bleeding (2.9% vs 1.1%), and operative complications (2% vs 0.6%) (P < 0.001 for all) compared to those without cirrhosis. Overtime, restrictive surgeries have grown in number (12%-71%) and complications rates have trended down in both groups. Cirrhotics undergoing bariatric surgery at low-volume centers (<50 procedures per year) and nonrestrictive surgery had a higher inpatient mortality rate (adjusted OR 4.50, 95% confidence interval 3.14-6.45, adjusted OR 4.00, 95% confidence interval 2.68-5.97, respectively).

DISCUSSION

Contemporary data indicate that among admissions for bariatric surgery, there is a shift to restrictive-type surgeries with an improvement in-hospital complications and mortality. However, patients with cirrhosis especially those at low-volume centers have significantly higher risk of worse outcomes (see Visual abstract, Supplementary Digital Content, http://links.lww.com/AJG/B648).

Obesity in Liver Transplantation: A Risk Factor for Unplanned Reoperation and Prolonged Operative Time

Selection of orthotopic liver transplantation (OLT) candidates is increasingly inclusive of patients with high BMI. We aim to characterize the influence of obesity on the surgical outcome measures of prolonged operative time and unplanned reoperation. We reviewed the records of obese and normal weight OLT recipients over a 10-year period from a single institution. Variables that trended ( P < 0.1) with endpoints on univariate analysis were put into multivariate logistic regression models to determine independent association ( P < 0.05). We included 195 obese and 171 normal weight OLT recipients in our study. On multivariate analysis, obesity was the only preoperative risk factor that trended with unplanned reoperation (odds ratio 2, P = 0.05). Similarly, only obesity remained independently associated with prolonged length of operation (defined as ≥275 minutes) on multivariate analysis (odds ratio 1.7, P = 0.04). In summary, obesity may make OLT more technically challenging and, thus, represents an independent risk factor for unplanned reoperations and prolonged operative time.

Impact of sarcopenic overweight on the outcomes after living donor liver transplantation

Background

The effect of body composition disturbances has been recently in focus. Sarcopenic obesity, a co-occurrence of low muscle mass and high body fat was reportedly predictive of high mortality in patients with cirrhosis. However, the impact of the interacting sarcopenia and overweight on the outcomes after liver transplantation is still unclear.

Methods

We evaluated 200 patients undergoing adult-to-adult living donor liver transplantation at our institution between January 2008 and November 2013 classified according to BMI and psoas muscle index (PMI) on admission to transplant into 4 subgroups; sarcopenic overweight (SO), sarcopenic non-overweight (SN), non-sarcopenic overweight and non-sarcopenic non-overweight (NN). Short-term outcomes and overall post-transplant survival were compared among the four subgroups.

Results

Sarcopenic patients with preoperative low PMI had higher incidence of postoperative bacteremia and major postoperative complications, and poorer overall post-transplant survival than non-sarcopenic patients with normal/high PMI (P<0.001, respectively). Overweight recipients had a significantly higher overall survival (OS) rate than non-overweight patients (P=0.021). SO subgroup (low PMI and BMI ≥25) had statistically indifferent incidence of postoperative bacteremia, major postoperative complications or overall post-transplant survival than other recipients. In contrast, SN subgroup (low PMI and BMI <25) had higher incidence of postoperative bacteremia (P<0.001), major postoperative complications (P<0.001) than the SO subgroup and possessed the poorest OS among the four recipient subgroups (P=0.001).

Conclusions

In living donor liver transplantation, preoperative SO did not confer added significant morbidity or mortality risks than the stand-alone sarcopenia.

Impact of super obesity on perioperative outcomes after hepatectomy: The weight of the risk

BACKGROUND

We evaluated perioperative outcomes in super obese patients (body mass index >50 kg/m²) undergoing liver resection using the American College of Surgeons National Surgical Quality Improvement Program.

METHODS

Patients undergoing hepatectomy recorded in the American College of Surgeons National Surgical Quality Improvement Program dataset from 2005 to 2015 were analyzed. Out of 21,228 hepatectomies in the National Surgical Quality Improvement Program dataset, 146 were performed on super obese patients.

RESULTS

Seventy-two percent of the super obese patients were female with a median age of 50.6 years, and 10% were classified as American College of Surgeons Class ≥III. In this group, 69.2% were hypertensive, 38.4% were diabetics, and 17.8% had dyspnea. The median operation time was 248 minutes in the super obese group, greater than any other body mass index class. Twenty-two percent of these patients required perioperative transfusion, although 74% underwent partial hepatectomies. Body mass index >50 kg/m² significantly increased morbidity in patients undergoing hepatectomies, almost 2-fold. Infectious complications increased by 86%, and the risk of developing critical care complications increased by 63%.

CONCLUSION

Our data show that super obesity (body mass index >50 kg/m²) is the strongest independent predictor of perioperative morbidity. These patients also are at much greater risk of infectious complications and critical care complications. Future studies should be conducted using weight loss strategies in extreme obese patients to reduce their risk of life-threatening complications after hepatectomy.

Systematic review with meta-analysis: post-operative complications and mortality risk in liver transplant candidates with obesity

BACKGROUND

International guidelines rate class III (morbid) obesity (body mass index [BMI]≥40 kg/m² ) as a relative contraindication for liver transplantation (LT) requiring further research. Moreover, data on the mortality risk in candidates with a BMI: 30-34.9 and 35-39.9 kg/m² (class I and class II obesity, respectively) are weak.

AIM

To compare post-operative complications and mortality risks in all obese candidates vs candidates with a BMI: 18.5-29.9 (normal/overweight) assumed as controls.

METHODS

We searched the Cochrane library, PubMed, Scopus, Web-of-Science and article reference lists, restricted to the English language, and selected cohort studies analysing the following outcomes: all-causes mortality (at 30 days, 1-2-3-5 years), post-operative and cardiopulmonary complications, hospital and intensive care unit (ICU) length of stay. Two reviewers independently extracted the studies data and a third one resolved discrepancies.

RESULTS

Twenty-four studies comprising 132 162 patients met the inclusion criteria. As compared to controls, mortality risk was increased at all time-periods (except at 3 years) for a BMI≥40, at 30 days for a BMI: 30-34.9 and in none of the considered time-periods for a BMI: 35-39.9. Post-operative complications were significantly higher for a BMI>30 and 30-34.9. Due to the shortage/absence of data, we evaluated cardiopulmonary complications, hospital and ICU length of stay only in the BMI≥30 category. In these patients, only cardiopulmonary complications were increased as compared to controls.

CONCLUSIONS

Morbid obesity has an impact on patients' survival after LT. However, since even a BMI>30 increases post-transplant complications, new strategies should be included in the LT programme to favour weight loss in all obese candidates.

Early Intervention With Live Donor Liver Transplantation Reduces Resource Utilization in NASH: The Toronto Experience

Background

In parallel with the obesity epidemic, liver transplantation for nonalcoholic steatohepatitis (NASH) is increasing dramatically in North America. Although survival outcomes are similar to other etiologies, liver transplantation in the NASH population has been associated with significantly increased resource utilization. We sought to compare outcomes between live donor liver transplantation (LDLT) and deceased donor liver transplantation (DDLT) at a high volume North American transplant center, with a particular focus on resource utilization.

Methods

The study population consists of primary liver transplants performed for NASH at Toronto General Hospital from 2000 to 2014. Recipient characteristics, perioperative outcomes, graft and patient survivals, and resource utilization were compared for LDLT versus DDLT.

Results

A total of 176 patients were included in the study (48 LDLT vs 128 DDLT). LDLT recipients had a lower model for end-stage liver disease score and were less frequently hospitalized prior to transplant. Estimated blood loss and early markers of graft injury were lower for LDLT. LDLT recipients had a significantly shorter hospitalization (intensive care unit, postoperative, and total hospitalization).

Conclusions

LDLT for NASH facilitates transplantation of patients at a less severe stage of disease, which appears to promote a faster postoperative recovery with less resource utilization.

Role of cardiotrophin-1 in the regulation of metabolic circadian rhythms and adipose core clock genes in mice and characterization of 24-h circulating CT-1 profiles in normal-weight and overweight/obese subjects

Cardiotrophin (CT)-1 is a regulator of glucose and lipid homeostasis. In the present study, we analyzed whether CT-1 also acts to peripherally regulate metabolic rhythms and adipose tissue core clock genes in mice. Moreover, the circadian pattern of plasma CT-1 levels was evaluated in normal-weight and overweight subjects. The circadian rhythmicity of oxygen consumption rate (Vo₂) was disrupted in aged obese CT-1-deficient (CT-1^-/-) mice (12 mo). Although circadian rhythms of Vo₂ were conserved in young lean CT-1^-/- mice (2 mo), CT-1 deficiency caused a phase shift of the acrophase. Most of the clock genes studied (Clock, Bmal1, and Per2) displayed a circadian rhythm in adipose tissue of both wild-type (WT) and CT-1^-/- mice. However, the pattern was altered in CT-1^-/- mice toward a lower percentage of the rhythm or lower amplitude, especially for Bmal1 and Clock. Moreover, CT-1 mRNA levels in adipose tissue showed significant circadian fluctuations in young WT mice. In humans, CT-1 plasma profile exhibited a 24-h circadian rhythm in normal-weight but not in overweight subjects. The 24-h pattern of CT-1 was characterized by a pronounced increase during the night (from 02:00 to 08:00). These observations suggest a potential role for CT-1 in the regulation of metabolic circadian rhythms.-López-Yoldi, M., Stanhope, K. L., Garaulet, M., Chen, X. G., Marcos-Gómez, B., Carrasco-Benso, M. P., Santa Maria, E. M., Escoté, X., Lee, V., Nunez, M. V., Medici, V., Martínez-Ansó, E., Sáinz, N., Huerta, A. E., Laiglesia, L. M., Prieto, J., Martínez, J. A., Bustos, M., Havel, P. J., Moreno-Aliaga, M. J. Role of cardiotrophin-1 in the regulation of metabolic circadian rhythms and adipose core clock genes in mice and characterization of 24-h circulating CT-1 profiles in normal-weight and overweight/obese subjects.

Tipping the Scales: Liver Transplant Outcomes of the Super Obese

OBJECTIVE

We aim to study outcomes in liver transplant recipients with body mass index (BMI) ≥50 using the United Network for Organ Sharing (UNOS) database.

METHODS

We reviewed patients undergoing liver transplantation recorded in the UNOS database from 1988 to 2013. Of 104,250 liver transplant procedures, 123 were performed on super obese patients.

RESULTS

Sixty-four percent of the super obese patients are female (64 %) and had a mean age 47 years (20-71). The mean BMI was 53.5 (50-72.86) and 16 % had diabetes. The mean Model for End-Stage Disease (MELD) score at transplant was 29.1 (6-53). It was found that BMI ≥50 increased 1.6-fold the risk of death within 30 days after liver transplantation. Graft failure was increased by 52 % and overall mortality was by 62 %. A 1:1 propensity score-matched analysis demonstrated that patients with BMI <50 have significantly better graft and overall patient survival than the super obese.

CONCLUSIONS

Overall, our data shows that BMI ≥50 is an independent predictor of perioperative mortality and graft and overall patient survival. Further studies are necessary to better understand predictors of outcomes in super obese patients.

From Child-Pugh to Model for End-Stage Liver Disease: Deciding Who Needs a Liver Transplant

This article reviews the historical evolution of the liver transplant organ allocation policy and the indications/contraindications for liver transplant, and provides an overview of the liver transplant evaluation process. The article is intended to help internists determine whether and when referral to a liver transplant center is indicated, and to help internists to counsel patients whose initial evaluation at a transplant center is pending.

Obesity-Associated Adipose Tissue Inflammation and Transplantation

Obesity is often associated with the development of adipose tissue (AT) inflammation, resulting in metabolic dysfunction and an increased risk for developing type 2 diabetes. It is also associated with multiple chronic diseases, including cardiovascular, liver, and kidney disease, and thus can contribute to organ failure. Several studies have investigated whether there is a correlation between obesity and outcomes in transplantation, but there is currently very limited information on the specific role of AT inflammation in the rejection process or on the overall function of the transplanted organ. Here, we provide a brief review of the current understanding of the cellular mechanisms that control obesity-associated AT inflammation and summarize knowledge about how obesity affects clinical outcomes following solid organ or hematopoietic stem cell transplantation. We also highlight opportunities for more research to better understand how obesity affects outcomes of transplantation.