A. Nardi

Liver Match, a prospective observational cohort study on liver transplantation in Italy: Study design and current practice of donor-recipient matching

BACKGROUND The Liver Match is an observational cohort study that prospectively enrolled liver transplantations performed at 20 out of 21 Italian Transplant Centres between June 2007 and May 2009. Aim of the study is to investigate the impact of donor/recipient matching on outcomes. In this report we describe the study methodology and provide a cross-sectional description of donor and recipient characteristics and of graft allocation. METHODS Adult primary transplants performed with deceased heart-beating donors were included. Relevant information on donors and recipients, organ procurement and allocation were prospectively entered in an ad hoc database within the National Transplant Centre web-based Network. Data were blindly analysed by an independent Biostatistical Board. RESULTS The study enrolled 1530 donor/recipient matches. Median donor age was 56 years. Female donors (n = 681, median 58, range 12-92 years) were older than males (n = 849, median 53, range 2-97 years, p < 0.0001). Donors older than 60 years were 42.2%, including 4.2% octogenarians. Brain death was due to non-traumatic causes in 1126 (73.6%) cases. Half of the donor population was overweight, 10.1% was obese and 7.6% diabetic. Hepatitis B core antibody (HBcAb) was present in 245 (16.0%) donors. The median Donor Risk Index (DRI) was 1.57 (>1.7 in 35.8%). The median cold ischaemia time was 7.3h (≥ 10 in 10.6%). Median age of recipients was 54 years, and 77.7% were males. Hepatocellular carcinoma (HCC) was the most frequent indication overall (44.4%), being a coindication in roughly 1/3 of cases, followed by viral cirrhosis without HCC (28.2%) and alcoholic cirrhosis without HCC (10.2%). Hepatitis C virus infection (with or without HCC) was the most frequent etiologic factor (45.9% of the whole population and 71.4% of viral-related cirrhosis), yet hepatitis B virus infection accounted for 28.6% of viral-related cirrhosis, and HBcAb positivity was found in 49.7% of recipients. The median Model for End Stage Liver Disease (MELD) at transplant was 12 in patients with HCC and 18 in those without. Multivariate analysis showed a slight but significant inverse association between DRI and MELD at transplant. CONCLUSIONS The deceased donor population in Italy has a high-risk profile compared to other countries, mainly due to older donor age. Almost half of the grafts are transplanted in recipients with HCC. Higher risk donors tend to be preferentially allocated to recipients with HCC, who are usually less ill and older. No other relevant allocation strategy is currently adopted at national level.

Serum soluble Fas levels in ovarian cancer.

Objective To determine the value of serum soluble Fas levels as a prognostic marker for survival of women with ovarian cancer and as a discriminator between benign and malignant adnexal masses. Methods Serum soluble Fas levels were measured with an enzyme-linked immunosorbent assay in 52 women with ovarian cancer, 30 women with benign ovarian cysts, and 35 healthy women. Results Median serum soluble Fas levels in women with ovarian cancer, women with benign ovarian cysts, and healthy women were 3.7 (range 1.6–14.5), 2.3 (range 1.3–4.1), and 1.5 ng/mL (range 0.1–5.6), respectively (P < .001). A univariate logistic regression model showed a significant influence of serum soluble Fas and CA 125 levels on the odds of presenting with ovarian cancer versus benign cysts (P < .001 and P = .001, respectively). In a multivariable logistic regression model for soluble Fas and CA 125, both markers showed a statistically significant influence on the odds of presenting with ovarian cancer versus benign cysts (P = .01 and P = .01, respectively). Increased pretreatment serum soluble Fas levels were associated with shortened disease-free and overall survival (P = .002 and P = .001, respectively). A multivariable Cox regression model identified serum soluble Fas levels as a significant prognostic factor for disease-free and overall survival, independent of tumor stage (P = .04 and P = .03, respectively). Conclusion Soluble Fas levels might be useful as a discriminator between benign ovarian cysts and ovarian cancer, adding to the information obtained with the use of the established tumor marker CA 125. Pretreatment serum soluble Fas levels also might be an independent prognostic factor for disease-free and overall survival.

Early postoperative prediction of cerebral damage after pediatric cardiac surgery

BACKGROUND Cerebral damage is a serious complication of pediatric cardiac surgery. Early prediction of actual risk can be useful in counseling of parents, and in early diagnosis and rehabilitation therapy. Also, if all children at risk could be identified therapeutic strategies to limit perioperative cerebral damage might be developed. The aim of this study is to create a mathematical model to predict risk of neurologic sequelae within 24 hours after surgery using simple and readily available clinical measurements. METHODS The hospital records of 534 children after cardiac surgery were reviewed. Variables examined were age at operation, diagnosis, use of cardiopulmonary bypass, arterial and central venous oxygen saturation, serum glucose, lactate and creatine kinase, mean arterial pressure, and body temperature. The endpoint for each study patient was the occurrence or lack of occurrence of seizures, movement or developmental disorders, cerebral hemorrhage, infarction, hydrocephalus, or marked cerebral atrophy. Univariate and multivariate regression analyses were used to evaluate the predictive power of the investigated factors as well as to create a predictive model. RESULTS In 6.26% of children symptoms of cerebral damage were found. Significant risk factors were age at surgery, more complex malformations, metabolic acidosis, and increased lactate (odds ratio: age, 0.882/yr [0.772-1.008]; complex malformations, 10.32 [1.32-80.28]; arterial pH more than 7.35 to 0.4 [0.18-0.89]; lactate -1.018 per mg/dL [1.006-1.03]). CONCLUSIONS It is possible to quantify the risk of appearance of symptoms of cerebral damage after cardiac surgery within 24 hours using simple and readily available clinical measurements.

Hepatitis B-core antibody positive donors in liver transplantation and their impact on graft survival: Evidence from the Liver Match cohort study

BACKGROUND & AIMS The appropriate allocation of grafts from HBcAb positive donors in liver transplantation is crucial, yet a consensus is still lacking. METHODS We evaluated this issue within Liver Match, a prospective observational Italian study. Data from 1437 consecutive, first transplants performed in 2007-2009 using grafts from deceased heart beating donors were analyzed (median follow-up: 1040 days). Of these, 219 (15.2%) were HBcAb positive. Sixty-six HBcAb positive grafts were allocated to HBsAg positive and 153 to HBsAg negative recipients. RESULTS 329 graft losses occurred (22.9%): 66 (30.1%) among 219 recipients of HBcAb positive grafts, and 263 (21.6%) among 1218 recipients of HBcAb negative grafts. Graft survival was lower in recipients of HBcAb positive compared to HBcAb negative donors, with unadjusted 3-year graft survival of 0.69 (s.e. 0.032) and 0.77 (0.013), respectively (log-rank, p=0.0047). After stratifying for recipient HBsAg status, this difference was only observed among HBsAg negative recipients (log rank, p=0.0007), 3-year graft survival being excellent (0.88, s.e. 0.020) among HBsAg positive recipients, regardless of the HBcAb donor status (log rank, p=0.4478). Graft loss due to de novo HBV hepatitis occurred only in one patient. At Cox regression, hazard ratios for graft loss were: MELD (1.30 per 10 units, p=0.0002), donor HBcAb positivity (1.56, p=0.0015), recipient HBsAg positivity (0.43, p <0.0001), portal vein thrombosis (1.99, p=0.0156), and DRI (1.41 per unit, p=0.0325). CONCLUSIONS HBcAb positive donor grafts have better outcomes when transplanted into HBsAg positive than HBsAg negative recipients. These findings suggest that donor HBcAb positivity requires more stringent allocation strategies.

Prevalence of paradoxically normal serum cholesterol in morbidly obese women

The paradox that cholesterol may be lower in extremely obese subjects versus those who are less overweight, although originally observed more than 40 years ago, has never been documented in a systematic fashion. We have therefore prospectively determined the body mass index (BMI) and serum cholesterol concentration in 3,312 women. The percentage of women with serum cholesterol in the normal range (<200 mg/dL) decreased with an increasing BMI, from 55% in women with a BMI less than 20 kg/m2 to 28% in those with a BMI of 30 to 35 kg/m2. Serum cholesterol greater than 300 mg/dL was found in only 2% of individuals with a BMI less than 20 kg/m2 but in 6% of the group with a BMI between 30 and 35 kg/m2. However, among morbidly obese women (BMI >40 kg/m2, n = 46), 39% presented with serum cholesterol less than 200 mg/dL and only one woman had serum cholesterol more than 300 mg/dL. With the BMI, the fitted regression model shows an increase in cholesterol for low BMIs, while cholesterol appears to decrease with larger values for the BMI. The age-dependent increase in cholesterol is more evident in younger women versus older women, where it tends to disappear. It is concluded that among morbidly obese women (BMI >40 kg/m2), there is a substantial subgroup with normal serum cholesterol.

Jeffreys priors for survival models with censored data

Abstract When prior information on model parameters is weak or lacking, Bayesian statistical analyses are typically performed with so-called “default” priors. We consider the problem of constructing default priors for the parameters of survival models in the presence of censoring, using Jeffreys’ rule. We compare these Jeffreys priors to the “uncensored” Jeffreys priors, obtained without considering censored observations, for the parameters of the exponential and log-normal models. The comparison is based on the frequentist coverage of the posterior Bayes intervals obtained from these prior distributions.

A Bayesian methodology to improve prediction of early graft loss after liver transplantation derived from the Liver Match study

BACKGROUND To generate a robust predictive model of Early (3 months) Graft Loss after liver transplantation, we used a Bayesian approach to combine evidence from a prospective European cohort (Liver-Match) and the United Network for Organ Sharing registry. METHODS Liver-Match included 1480 consecutive primary liver transplants performed from 2007 to 2009 and the United Network for Organ Sharing a time-matched series of 9740 transplants. There were 173 and 706 Early Graft Loss, respectively. Multivariate analysis identified as significant predictors of Early Graft Loss: donor age, donation after cardiac death, cold ischaemia time, donor body mass index and height, recipient creatinine, bilirubin, disease aetiology, prior upper abdominal surgery and portal thrombosis. RESULTS A Bayesian Cox model was fitted to Liver-Match data using the United Network for Organ Sharing findings as prior information, allowing to generate an Early Graft Loss-Donor Risk Index and an Early Graft Loss-Recipient Risk Index. A Donor-Recipient Allocation Model, obtained by adding Early Graft Loss-Donor Risk Index to Early Graft Loss-Recipient Risk Index, was then validated in a distinct United Network for Organ Sharing (year 2010) cohort including 2964 transplants. Donor-Recipient Allocation Model updating using the independent Turin Transplant Centre dataset, allowed to predict Early Graft Loss with good accuracy (c-statistic: 0.76). CONCLUSION Donor-Recipient Allocation Model allows a reliable donor and recipient-based Early Graft Loss prediction. The Bayesian approach permits to adapt the original Donor-Recipient Allocation Model by incorporating evidence from other cohorts, resulting in significantly improved predictive capability.

Recipient female gender is a risk factor for graft loss after liver transplantation for chronic hepatitis C: Evidence from the prospective Liver Match cohort.

BACKGROUND Female gender has been reported to be a risk factor for graft loss after liver transplantation for hepatitis C virus (HCV)-related cirrhosis but evidence is limited to retrospective studies. AIMS To investigate the impact of recipient gender and donor/recipient gender mismatch on graft outcome. METHODS We performed a survival analysis of a cohort of 1530 first adult transplants enrolled consecutively in Italy between 2007 and 2009 and followed prospectively. After excluding possible confounding factors (fulminant hepatitis, human immunodeficiency virus co-infection, non-viremic anti-HCV positive subjects), a total of 1394 transplant recipients (604 HCV-positive and 790 HCV-negative) were included. RESULTS Five-year graft survival was significantly reduced in HCV-positive patients (64% vs 76%, p=0.0002); Cox analysis identified recipient female gender (HR=1.44, 95% CI 1.03-2.00, p=0.0319), Mayo clinic End stage Liver Disease score (every 10 units, HR=1.25, 95% CI 1.03-1.50; p=0.022), portal thrombosis (HR=2.40, 95% CI 1.20-4.79, p=0.0134) and donor age (every 10 years, HR=1.14, 95% CI 1.05-1.24, p=0.0024) as independent determinants of graft loss. All additional mortality observed among female recipients was attributable to severe HCV recurrence. CONCLUSIONS This study unequivocally shows that recipient female gender unfavourably affects the outcome of HCV-infected liver grafts.

An a priori prediction model of response to peginterferon plus ribavirin dual therapy in naïve patients with genotype 1 chronic hepatitis C

BACKGROUND Aim was to select naïve patients with genotype 1 chronic hepatitis C having a high probability of response to Peg-interferon+ribavirin therapy. METHODS In 1073 patients (derivation cohort), predictors of rapid and sustained virological response were identified by logistic analysis; regression coefficients were used to generate prediction models for sustained virological response. Probabilities at baseline and treatment week 4 were utilized to develop a decision rule to select patients with high likelihood of response. The model was then validated in 423 patients (validation cohort). RESULTS In the derivation cohort, 257 achieved rapid virological response and 818 did not, with sustained virological response rates of 80.2% and 25.4%, respectively; interleukin-28B polymorphisms, fibrosis staging, gamma-glutamyl transferase, and viral load predicted sustained virological response. Assuming a <30% sustained virological response probability for not recommending Peg-interferon+ribavirin, 100 patients (25.6%) in the validation cohort were predicted a priori to fail this regimen. Assuming a ≥80% sustained virological response probability as a threshold to continue with Peg-interferon+ribavirin, 61 patients were predicted to obtain sustained virological response, and 55 of them (90.2%) eventually did. CONCLUSIONS This model uses easily determined variables for a personalized estimate of the probability of sustained virological response with Peg-interferon+ribavirin, allowing to identify patients who may benefit from conventional therapy.

The present profile of chronic hepatitis B virus infection highlights future challenges

BACKGROUND Chronic hepatitis B virus (HBV) infection remains a primary cause of morbidity and mortality worldwide. AIM The study is aimed at updating the clinical and epidemiological profile of chronic HBV infection in Italy. METHODS A cross-sectional multicenter prospective study enrolled consecutive HBsAg positive patients seen in 73 Italian centers in the period 2012-2015. Individual patient data were collected using an electronic platform and analyzed using standard statistical methods. RESULTS Among 2877 HBsAg positive individuals (median age 49.8 years, 68% males), 27% were non-Italian natives (NINs); 20% had chronic infection, 58.5% chronic hepatitis and 21.5% cirrhosis. Among NINs, age was younger, male gender was less prevalent and liver disease less advanced than in Italians (all p < 0.0001). HBeAg positive cases were 23.6% among NINs vs 8.2% in Italians (p < 0.0001); HDV coinfections 11.1% vs 7.3% (p = 0.006) and HCV coinfections 2.3% vs 4.2% (p = 0.017), respectively. Anti-HDV or anti-HCV antibodies were detected more frequently in patients with cirrhosis. Fifty percent of NINs with cirrhosis were aged below 45 years. CONCLUSION The study offers an insight into the evolving burden of chronic hepatitis B virus infection in the near future and highlights new territories for public health interventions.