The British Society of Gastroenterology/UK-PBC primary biliary cholangitis treatment and management guidelines.

Primary biliary cholangitis (formerly known as primary biliary cirrhosis, PBC) is an autoimmune liver disease in which a cycle of immune mediated biliary epithelial cell injury, cholestasis and progressive fibrosis can culminate over time in an end-stage biliary cirrhosis. Both genetic and environmental influences are presumed relevant to disease initiation. PBC is most prevalent in women and those over the age of 50, but a spectrum of disease is recognised in adult patients globally; male sex, younger age at onset (<45) and advanced disease at presentation are baseline predictors of poorer outcome. As the disease is increasingly diagnosed through the combination of cholestatic serum liver tests and the presence of antimitochondrial antibodies, most presenting patients are not cirrhotic and the term cholangitis is more accurate. Disease course is frequently accompanied by symptoms that can be burdensome for patients, and management of patients with PBC must address, in a life-long manner, both disease progression and symptom burden. Licensed therapies include ursodeoxycholic acid (UDCA) and obeticholic acid (OCA), alongside experimental new and re-purposed agents. Disease management focuses on initiation of UDCA for all patients and risk stratification based on baseline and on-treatment factors, including in particular the response to treatment. Those intolerant of treatment with UDCA or those with high-risk disease as evidenced by UDCA treatment failure (frequently reflected in trial and clinical practice as an alkaline phosphatase >1.67 × upper limit of normal and/or elevated bilirubin) should be considered for second-line therapy, of which OCA is the only currently licensed National Institute for Health and Care Excellence recommended agent. Follow-up of patients is life-long and must address treatment of the disease and management of associated symptoms.

Senescence in chronic liver disease: Is the future in aging?

Cellular senescence is a fundamental, complex mechanism with an important protective role present from embryogenesis to late life across all species. It limits the proliferative potential of damaged cells thus protecting against malignant change, but at the expense of substantial alterations to the microenvironment and tissue homeostasis, driving inflammation, fibrosis and paradoxically, malignant disease if the process is sustained. Cellular senescence has attracted considerable recent interest with recognition of pathways linking aging, malignancy and insulin resistance and the current focus on therapeutic interventions to extend health-span. There are major implications for hepatology in the field of fibrosis and cancer, where cellular senescence of hepatocytes, cholangiocytes, stellate cells and immune cells has been implicated in chronic liver disease progression. This review focuses on cellular senescence in chronic liver disease and explores therapeutic opportunities.

Selective insulin resistance in hepatocyte senescence.

Insulin resistance has been described in association with chronic liver disease for decades. Hepatocyte senescence has been demonstrated in chronic liver disease and as many as 80% of hepatocytes show a senescent phenotype in advanced liver disease. The aim of this study was to understand the role of hepatocyte senescence in the development of insulin resistance. Senescence was induced in HepG2 cells via oxidative stress. The insulin metabolic pathway was studied in control and senescent cells following insulin stimulation. GLUT2 and GLUT4 expressions were studied in HepG2 cells and human liver tissue. Further, GLUT2 and GLUT4 expressions were studied in three independent chronic liver disease cohorts. Signalling impairment distal to Akt in phosphorylation of AS160 and FoxO1 was evident in senescent HepG2 cells. Persistent nuclear localisation of FoxO1 was demonstrated in senescent cells despite insulin stimulation. Increased GLUT4 and decreased GLUT2 expressions were evident in senescent cells, human cirrhotic liver tissue and publically available liver disease datasets. Changes in GLUT expressions were associated with a poor clinical prognosis. In conclusion, selective insulin resistance is evident in senescent HepG2 cells and changes in GLUT expressions can be used as surrogate markers of hepatocyte senescence.

Reliability of magnetic resonance elastography using multislice two-dimensional spin-echo echo-planar imaging (SE-EPI) and three-dimensional inversion reconstruction for assessing renal stiffness.

BACKGROUND: To evaluate the reliability of MRE using a spin-echo echo-planar imaging (SE-EPI) renal MRE technique in healthy volunteers. METHODS: Institutional review board approved prospective study in which all participants provided written informed consent. Sixteen healthy volunteers comprising seven males and nine females with a median age of 35 years (age range: 23 to 59 years) were included. Coronal 90 Hz and 60 Hz MRE acquisitions were performed twice within a 30-min interval between examinations. Renal MRE reliability was assessed by (i) test-retest repeatability, and (ii) inter-rater agreement between two independent readers. The MRE-measured averaged renal stiffness values were evaluated using: intraclass correlation coefficient (ICC), Bland-Altman and the within-subject coefficient of variation (COV). RESULTS: For test-retest repeatability, Bland-Altman showed a mean stiffness difference between examinations of 0.07 kPa (95% limits of agreement: -1.41, 1.54) at 90 Hz and 0.01 kPa (95% limits of agreement: -0.51, 0.53) at 60 Hz. Coefficient of repeatability was 1.47 kPa and 0.52 kPa at 90 Hz and 60 Hz, respectively. The within-subject COV was 13.6% and 7.7% at 90 Hz and 60 Hz, respectively. ICC values were 0.922 and 0.907 for test-retest repeatability and 0.998 and 0.989 for inter-rater agreement, respectively (P < 0.001). CONCLUSION: SE-EPI renal MRE is a reliable technique.

Magnetic resonance elastography in the detection of hepatorenal syndrome in patients with cirrhosis and ascites.

OBJECTIVE: Hepatorenal syndrome (HRS) is the most lethal cause of renal impairment in cirrhosis. Magnetic resonance elastography (MRE) is a diagnostic test that characterises tissues based on their biomechanical properties. The aim of this study was to assess the feasibility of MRE for detecting HRS in cirrhotic patients. METHODS: A prospective diagnostic investigation was performed. Renal MRE was performed on 21 hospitalised patients with cirrhosis and ascites. Six patients had HRS, one patient had non-HRS renal impairment, and 14 patients had normal renal function. The MRE-measured renal stiffness was compared against the clinical diagnosis as determined by clinical review alongside laboratory and radiologic results. RESULTS: The MRE-measured renal stiffness was significantly lower in patients with HRS (median stiffness of 3.30 kPa at 90 Hz and 2.62 kPa at 60 Hz) compared with patients with normal renal function (median stiffness of 5.08 kPa at 90 Hz and 3.41 kPa at 60 Hz) (P ≤ 0.014). For the detection of HRS, MRE had an area under the receiver operating characteristic curve of 0.94 at 90 Hz and 0.89 at 60 Hz. MRE had excellent inter-rater agreement, as assessed by Bland-Altman and intraclass correlation coefficient (> 0.9). CONCLUSION: MRE shows potential in the detection of HRS. KEY POINTS: • Magnetic resonance elastography (MRE) shows promise in the detection of hepatorenal syndrome. • MRE has the potential to track renal disease in a clinical population. • MRE is a reliable diagnostic test with excellent inter-rater agreement.

Induced pluripotent stem cells: from Nobel Prizes to clinical applications.

Advances in basic hepatology have been constrained for many years by the inability to culture primary hepatocytes in vitro, until just over five years ago when the scientific playing field was changed beyond recognition with the demonstration that human skin fibroblasts could be reprogrammed to resemble embryonic cells. The reprogrammed cells, known as induced pluripotent stem cells (iPSCs), were then shown to have the capacity to re-differentiate into almost any human cell type, including hepatocytes. The unlimited number and isogenic nature of the cells that can be generated from tiny fragments of tissue have massive implications for the study of human liver diseases in vitro. Of more immediate clinical importance were recent data demonstrating precision gene therapy on patient specific iPSCs, which opens up the real and exciting possibility of autologous hepatocyte transplantation as a substitute for allogeneic whole liver transplantation, which has been an effective approach to end-stage liver disease, but one that has now been outstripped by demand. In this review, we describe the historical development, current technology and potential clinical applications of induced pluripotency, concluding with a perspective on possible future directions in this dynamic field.

γ-H2AX+CD8+ T lymphocytes cannot respond to IFN-α, IL-2 or IL-6 in chronic hepatitis C virus infection.

BACKGROUND & AIMS: Age is the dominant prognostic factor influencing the natural history of hepatitis C virus (HCV) infection and treatment response. Accelerated lymphocyte telomere shortening in HCV infection correlates with adverse clinical outcomes. Critical telomere shortening generates double-stranded DNA breaks (DSB) inducing the DNA damage response, leading to replicative senescence. The phenotype and function of CD8+ T lymphocytes and the in vitro response to IFN-α in relation to the DNA damage response were investigated in patients with chronic HCV infection. METHODS: CD8+ T lymphocytes with DSB were identified by expression of γ-H2AX (Ser-139) in 134 HCV-exposed subjects and 27 controls. Telomere length was determined by flow-FISH; cytokine expression by intracellular cytokine staining; in vitro responses to IFN-α, IL-2 or IL-6 by phospho-STAT1 (Y701) or phospho-STAT5 (Y694) expression. RESULTS: The proportion of circulating CD8+γ-H2AX+ T lymphocytes rose with increasing fibrosis stage (p=0.0023). CD8+γ-H2AX+ T lymphocytes were enriched in liver compared to blood (p=0.03). CD8+γ-H2AX+ T lymphocytes demonstrated increased IFN-γ (p=0.02) and reduced IL-2 expression (p=0.02). CD8+γ-H2AX+ T lymphocytes failed to phosphorylate STAT1 in response to IFN-α compared to unfractionated CD8+ T lymphocytes (p <0.0001). More widespread failure of Jak/Stat signalling in CD8+γ-H2AX+ T lymphocytes was suggested by impaired phosphorylation of STAT1 with IL-6 (p=0.002) and STAT5 with IL-2 (p=0.0039) compared to unfractionated CD8+ T-lymphocytes. CONCLUSIONS: In chronic HCV infection, CD8+γ-H2AX+ T lymphocytes are highly differentiated with shortened telomeres, are more frequent within the liver, are associated with severe fibrosis and fail to activate Jak/Stat pathways in response to IFN-α, IL-2 or IL-6, perhaps explaining treatment failure in those with severe fibrosis.

Sustained telomere length in hepatocytes and cholangiocytes with increasing age in normal liver.

UNLABELLED: Telomeres, a validated biomarker of aging, comprise multiple nucleotide repeats capping chromosomes that shorten with each cell cycle until a critical length is achieved, precipitating cell senescence. Only two previous studies focused on the effect of aging in "normal" liver tissue, but these studies were compromised by small sample size, limited age range, tissue derived from individuals with an increased risk of senescence, and the use of liver homogenates. We developed a robust large-volume, four-color quantitative fluorescent in situ hybridization technique to measure telomere length in large numbers of hepatocytes, Kupffer cells, hepatic stellate cells, CD4-positive and CD8-positive lymphocytes, and cholangiocytes. Following validation against the gold standard (Southern blotting), the technique was applied to normal archived paraffin-embedded liver tissue obtained following reperfusion of implanted donor liver. We studied 73 highly selected donors aged 5-79 years with a short medical illness preceding death and no history of liver disease, reperfusion injury, or steatosis and normal graft function 1-year posttransplantation. Cholangiocytes had significantly longer telomeres compared with all other intrahepatic lineages over a wide age range (P < 0.05). Age-related telomere attrition was restricted to sinusoidal cells (i.e., Kupffer cells [P = 0.0054] and stellate cells [P = 0.0001]). Cholangiocytes and hepatocytes showed no age-related telomere shortening. CONCLUSION: In normal liver and over a broad age range, cholangiocytes have longer telomeres than all other intrahepatic lineages. Age-related telomere length decline is restricted to Kupffer cells and stellate cells.

CD4+ T-lymphocyte telomere length is related to fibrosis stage, clinical outcome and treatment response in chronic hepatitis C virus infection.

BACKGROUND & AIMS: Increasing age is associated with impaired immune function and in chronic HCV infection specifically, with progressive fibrosis, liver failure, HCC and impaired responses to antiviral therapy. T-lymphocyte telomere length declines with age. We hypothesised that shorter T-lymphocyte telomere length would be associated with poor clinical outcome in HCV infection. METHODS: Circulating T-lymphocyte telomere length, an objective measure of immune senescence, was measured by flow-FISH in 135 HCV-RNA-positive, treatment-naïve patients and 41 healthy controls in relation to clinical outcome. RESULTS: Shorter CD4+CD45RO+ T-lymphocyte telomeres were associated with severe fibrosis (p=0.003), independent of male sex (p=0.04), CMV positivity (p=0.003), previous HBV infection (p=0.007), and age (p=ns) in viraemic patients compared to controls. There were inverse correlations between CD4+CD45RO+ telomere length and fibrosis stage (p<0.001), portal tract inflammatory grade (p=0.035), prothrombin time (p<0.001) and bilirubin (p=0.001). One hundred and twenty-four viraemic individuals were followed prospectively to a composite endpoint of death, hepatic decompensation or HCC. Independent of age, those with shorter CD4+CD45RO+ telomeres were less likely to be complication free after 2-years than those with longer telomeres (86% versus 96%, p=0.009) with an age-adjusted hazard ratio of 0.93 (0.90-0.96). In addition, CD4+CD45RO+ telomere length predicted successful antiviral therapy (p=0.001) independent of other factors. CONCLUSIONS: CD4+ T-lymphocyte telomere length, independent of age, was related to inflammatory grade, fibrosis stage, laboratory indices of severity, subsequent hepatic decompensation and treatment outcome in patients with chronic HCV infection.

Features of immune senescence in liver transplant recipients with established grafts.

Immune senescence is the normal process whereby the human immune system ages, but becomes less effective. We investigated whether liver transplant recipients have features of immune senescence. Lymphocytes from 97 liver transplant recipients with established grafts and 41 age-matched and sex-matched controls were subjected to an 8-color flow cytometry assay that measured expression of killer cell lectin-like receptor subfamily G member 1, cluster of differentiation 127 (CD127), CD45RO, CD27, CD28, CD4, CD8, and CD57. Lymphocyte telomere length was assessed by flow-fluorescence in situ hybridization. Cases were compared with controls for each marker of immune senescence using a Mann-Whitney U test. For liver transplant recipients, linear regression analyses identified associations between markers of immune senescence and clinical or demographic characteristics. Lymphocytes from liver transplant recipients expressed more phenotypic markers of maturity than did lymphocytes from controls. Lymphocyte telomeres were shorter in liver transplant recipients than in controls. Age, hepatocellular carcinoma at transplantation, and skin malignancy developing after transplantation were associated independently with shortened lymphocyte telomeres. Increasing age and previous cytomegalovirus infection were associated independently with phenotypic markers of lymphocyte maturity. Thus, lymphocytes from liver transplant recipients are older "biologically" than lymphocytes from age-matched and sex-matched controls. Hepatocellular carcinoma at transplantation, subsequent skin malignancy, and previous cytomegalovirus infection are associated with lymphocyte senescence in liver transplant recipients.

Tumor recurrence following liver transplantation for hepatocellular carcinoma: role of tumor proliferation status.

The selection of patients with hepatocellular carcinoma for liver transplantation is currently based on the size and number of tumors to minimize the risk of recurrence. These criteria measure tumor bulk but may not reflect tumor behavior accurately. A biological marker of tumor behavior could aid with patient selection further. The aims of this study were to determine factors associated with a higher risk of tumor recurrence and to assess the role of tumor proliferation status with respect to recurrence following transplantation. Pathological data on 67 patients who underwent transplantation for hepatocellular carcinoma were reviewed, and tumor proliferation was assessed by minichromosome maintenance protein-2 (MCM-2) and cyclin A expression. A Cox regression analysis of factors related to tumor recurrence and overall survival was carried out. Recurrence-free survival was assessed according to compatibility with selection criteria, vascular invasion, and proliferation status. Tumor size, vascular invasion, and highest MCM-2 expression were associated with tumor recurrence by multivariate analysis (P < 0.02). Recurrence-free survival was significantly better for those patients without vascular invasion, those who were within the Milan, University of California San Francisco (UCSF), or Up-to-Seven selection criteria, and those with lower expression of MCM-2. In conclusion, tumors meeting the Milan, UCSF, or Up-to-Seven selection criteria had a lower rate of recurrence following liver transplantation. Vascular invasion and tumor proliferation status were associated with the risk of recurrence independently of tumor size. Biopsy of larger tumors to assess proliferative activity could identify those at lower risk of recurrence who could also benefit from liver transplantation.

The Alpha-1 Antitrypsin Polymer Load Correlates With Hepatocyte Senescence, Fibrosis Stage and Liver-Related Mortality.

BACKGROUND: Alpha-1 antitrypsin deficiency (AATD) is an important, inherited cause of chronic liver disease. Marked variation in fibrosis stages in patients with homozygous deficiency and those factors that determine whether heterozygous carriers develop liver fibrosis, remain unexplained. Murine studies implicate polymerized alpha-1 antitrypsin (AAT) within hepatocytes as pathogenic. AIMS AND METHODS: The relationship between the quantity of polymerized AAT within hepatocytes (polymer load), stage of hepatic fibrosis and liver-related clinical outcomes (death, evolution to hepatocellular carcinoma, or need for liver transplantation) were investigated using liver tissue from 92 patients at first presentation with either homozygous or heterozygous AATD. Further tissue-based studies were undertaken to determine if polymerized AAT was associated with failure of cell cycle progression, accelerated aging or hepatocyte senescence by immunohistochemical analysis. RESULTS: The AAT polymer load correlated closely with hepatic fibrosis stage and long-term clinical outcome, independent of homozygous or heterozygous status. AAT polymers within hepatocytes correlated closely with failure of cell cycle progression assessed using cell cycle phase markers, accelerated aging manifest as shortened telomeres and other markers consistent with hepatocyte senescence manifest as the presence of nuclear p21 expression and enlarged nuclei. The proportion of p21 positive hepatocytes or hepatocytes with enlarged nuclei correlated with hepatic fibrosis stage and the long-term clinical outcome. CONCLUSION: These data suggest that accumulation of AAT polymers within hepatocytes drives senescence. Quantitation of both the AAT polymer load or hepatocyte senescence markers correlated with hepatic fibrosis stage and the long-term clinical outcome. Either or both could be considered markers of disease severity and treatment response in clinical trials.

Complement abnormalities in acquired lipodystrophy revisited.

CONTEXT: Lipodystrophy is a heterogeneous condition characterized by an inherited or acquired deficiency in the number of adipocytes required for the storage of energy as triglycerides. Acquired lipodystrophy is frequently associated with other autoimmune disorders. One well-studied form is characterized by the selective loss of upper body fat in association with activation of the alternative complement pathway by C3 nephritic factor, low complement factor C3, and mesangiocapillary glomerulonephritis. OBJECTIVE: We now describe an immunologically distinct form of acquired generalized lipodystrophy, with evidence of activation of the classical complement pathway (low C4) and autoimmune hepatitis. Patients and Research Design: Three unrelated patients with acquired lipodystrophy and low complement C4 levels are described. In vitro analysis of the complement pathway was undertaken to determine the reason for the low C4 complement levels. Biopsies were obtained from liver, bone marrow, and adipose tissue for histological analysis. RESULTS: All three patients manifested near-total lipodystrophy, chronic hepatitis with autoimmune features, and low C4 complement levels. Additional autoimmune diseases, including severe hemolytic anemia, autoimmune thyroid disease, and polyneuropathy, were variably present. Detailed studies of complement pathways suggested constitutive classical pathway activation. CONCLUSIONS: Although the previously described syndrome, which typically results in a cephalad pattern of partial lipodystrophy, results from activation of the alternative complement pathway, this form, in which lipodystrophy is generalized, is associated with activation of the classical pathway. Future therapeutic approaches to these disorders may benefit from being tailored to their distinct immunopathogenesis.

Minichromosome maintenance protein-2-positive portal tract lymphocytes distinguish acute cellular rejection from hepatitis C virus recurrence after liver transplantation.

Hepatitis C virus (HCV) is a leading indication for liver transplantation worldwide, but graft infection with HCV frequently leads to hepatic fibrosis. Acute cellular rejection (ACR) can be difficult to distinguish confidently from HCV, even with histology, but accurate diagnosis is critical because treatment of ACR may accelerate HCV-related graft injury. Immunohistochemistry was undertaken on 99 liver biopsies from 31 patients with HCV graft infection, 22 patients with ACR, and 11 patients with HCV infection and unexplained graft dysfunction to investigate whether lymphocyte expression of minichromosome maintenance protein-2 (Mcm-2), a marker of licensed cell cycle entry, assessed in a novel semiautomated system could distinguish between ACR and graft infection with HCV. The portal tract area was greater in ACR than in HCV graft infection (P = 0.027), but there was considerable overlap. However, both the number of Mcm-2-positive lymphocytes per portal tract and the number of Mcm-2-positive lymphocytes per millimeter squared of portal tract distinguished between ACR and HCV graft infection (P < 0.0001). A cutoff value of 107 positive cells per portal tract had a sensitivity of 81.8% and a specificity of 91.9% (positive predictive value of 66.67% and negative predictive value of 95.75%). Of 11 HCV-infected patients with an uncertain diagnosis, 7 were deemed ultimately to have HCV graft infection, and 4 had superimposed corticosteroid-responsive ACR. The number of Mcm-2-positive cells per portal tract and per millimeter squared of portal tract again distinguished clearly between the groups (P = 0.012). In conclusion, lymphocyte Mcm-2 expression is a useful adjunct to histology in differentiating between HCV graft infection and ACR. Patients with a low number of Mcm-2-positive portal tract lymphocytes are less likely to have ACR.

Histological changes in HCV antibody-positive, HCV RNA-negative subjects suggest persistent virus infection.

UNLABELLED: It is unclear whether hepatitis C virus (HCV) has been eradicated or persists at a low level in HCV antibody-positive HCV RNA-negative individuals. The natural history and liver histology are not well characterized. One hundred seventy-two HCV antibody-positive, serum HCV RNA-negative patients underwent diagnostic liver biopsy between 1992 and 2000 and were followed a median 7 years (range, 5-12). Patients with any possible cause of liver injury other than HCV were excluded. A single histopathologist scored sections using Ishak criteria. Characterization of the inflammatory infiltrate in selected cases used a novel semiquantitative technique and compared with HCV RNA-positive patients and healthy controls. One hundred two patients were excluded because of a risk factor for liver injury other than HCV. Seventy patients met the study criteria; four (5.7%) became HCV RNA-positive during follow-up. Sixty-six cases remained HCV RNA-negative; five (7.5%) had a normal liver biopsy; 54 (82%) had fibrosis (stage 2 or 3 in 16 (24%)). Nonviremic cases revealed expanded portal tracts (P < 0.05), with fewer CD4+ (P < 0.05) and more CD8+ cells (P < 0.05) than healthy controls, but were indistinguishable from HCV RNA-positive cases for these parameters. Lobular CD4 staining, absent in healthy controls, was noted in both HCV RNA-negative and -positive cases and was more marked in the latter (P < 0.05) with a sinusoidal lining cell distribution. CONCLUSION: Nonviremic HCV antibody-positive patients have a liver biopsy that is usually abnormal. Fibrosis was present in most with similar inflammatory infiltrate to viremic cases. The presence of a CD8+ rich inflammatory infiltrate suggests an ongoing immune response in the liver, supporting the view that HCV may persist in the liver in the majority of HCV RNA-negative cases.

A real-time Taqman method for hepatitis C virus genotyping and methods for further subtyping of isolates.

The HCV genome is highly heterogeneous; more and more genotypes, each with several distinct subtypes, are being identified around the world. Knowledge of genotype is important for planning of treatment regimes, whereas subtype identification is useful in epidemiological studies and outbreak investigation. We describe HCV genotyping and subtyping assays, based on real-time PCR, that are sensitive, specific, and reliable. These assays provide fast, accurate, and convenient methods for HCV genotyping/subtyping to support clinical practice.

The case for combination antiviral therapy for chronic hepatitis B virus infection.

The treatment of hepatitis B virus (HBV) infection has been revolutionised in the past decade by the increased availability of effective antiviral agents. Many studies have shown the benefits of single agent therapy, but there is an alarming and rising rate of viral resistance, and clear evidence that viruses that harbour resistant mutations can cause liver disease and death. Current national guidelines for the treatment of HBV recommend a programme that starts with monotherapy, followed by sequential monotherapy or add-on therapy for those infections in which mutations have arisen. Very few studies starting with combination therapy have been undertaken, so there is little evidence of the clinical benefit of this approach to treatment. The studies that have been done have been short term and have concentrated on clinical parameters rather than virological resistance, which is likely to be the key determinant in the longer term. We argue that we should not wait for the evidence to use combination therapy for the treatment of HBV, since such trials may never be done and it would take several years for a benefit to become apparent. In the meantime, multidrug-resistant strains continue to hinder HBV control.

A single centre experience of liver disease in adults with cystic fibrosis 1995-2006.

BACKGROUND: Liver disease is an important cause of death in adults with cystic fibrosis (CF). Ursodeoxycholic acid (UDCA) may slow progression. Managing varices and timely evaluation for liver transplantation are important. METHODS: Adults with CF underwent annual review. Abnormalities of liver function tests or ultrasound prompted referral to the CF/liver clinic where UDCA was commenced. Endoscopic surveillance for varices was undertaken if ultrasound suggested portal hypertension. RESULTS: 154 patients were followed for a median 5 years. 43 had significant liver disease, 29 had cirrhosis with portal hypertension and 14 had ultrasound evidence of cirrhosis without portal hypertension. All started UDCA. Only one patient developed chronic liver failure and none required liver transplantation. 27 underwent endoscopy; 1 required variceal banding, the others had insignificant varices. Ultrasound was normal in 97 patients while five had steatosis; nine further patients had splenomegaly but no other evidence of portal hypertension. Neither spleen size nor platelet count correlated with portal hypertension. CONCLUSIONS: Liver disease was common in adults with CF but disease progression was rare. Thus liver disease detected and closely monitored in adults appeared to have a milder course than childhood CF. Splenomegaly, unrelated to portal hypertension may be a consequence of CF.

Event-biased referral can distort estimation of hepatitis C virus progression rate to cirrhosis, and of prognostic influences.

OBJECTIVE: To investigate how cirrhosis-biased referral to liver clinics can explain the wide variation in progression rates for differently recruited cohorts and, in particular, for liver clinic cohorts compared to community-based studies of the natural history of hepatitis C virus (HCV). STUDY DESIGN AND SETTING: A simulation was designed to illustrate the sort of referral bias pattern that is capable of converting a 20-year progression rate to cirrhosis of around 5% in the community of HCV-infected individuals into a 20% progression rate for patients who have been selectively referred to a liver clinic. RESULTS: We show that event-biased recruitment, such as occurs if referral to liver clinics is increasingly likely the closer a patient is to cirrhosis, can produce severely upwardly biased estimates of progression rates, can dampen the influence of "poor prognostic" factors (such as history of excessive alcohol consumption), but overrepresents the proportion of patients in the community of HCV-infected individuals who have poor prognosis. CONCLUSION: When attempting to establish the natural history of new diseases with long incubation periods, researchers should be on the look out for potential biases that result from the way patients are referred into clinical cohorts.