C. Gavrila

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.

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.

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.