Updating prognosis in primary biliary cirrhosis using a time-dependent Cox regression model. PBC1 and PBC2 trial groups

Primary Biliary Cholangitis: Promising Emerging Innovative Therapies and Their Impact on GLOBE Scores

Primary biliary cholangitis (PBC), previously referred to as primary biliary cirrhosis, is an autoimmune disorder leading to the destruction of intra-hepatic bile ducts. If untreated, progressive bile duct damage and cholestasis can lead to ductopenia and result in cirrhosis. Ursodiol, the first drug approved for PBC, has changed the natural history of this disease and improved patient outcomes. Subsequently, several new prediction models incorporating a response to ursodiol were developed. These include the GLOBE score, which was shown to predict long-term outcomes in patients with PBC. In 2016, obeticholic acid (OCA) became the second drug to be approved by the FDA, predominantly based on improvement in alkaline phosphatase (ALP) levels. This trial has subsequently influenced the design of clinical trials. Several drugs are currently being evaluated as therapeutic options for PBC, with improvement in ALP being a main endpoint. In this review, we will discuss the impact of new therapies on GLOBE scores in patients with PBC.

Multivariate longitudinal data for survival analysis of cardiovascular event prediction in young adults: insights from a comparative explainable study

BACKGROUND

Multivariate longitudinal data are under-utilized for survival analysis compared to cross-sectional data (CS - data collected once across cohort). Particularly in cardiovascular risk prediction, despite available methods of longitudinal data analysis, the value of longitudinal information has not been established in terms of improved predictive accuracy and clinical applicability.

METHODS

We investigated the value of longitudinal data over and above the use of cross-sectional data via 6 distinct modeling strategies from statistics, machine learning, and deep learning that incorporate repeated measures for survival analysis of the time-to-cardiovascular event in the Coronary Artery Risk Development in Young Adults (CARDIA) cohort. We then examined and compared the use of model-specific interpretability methods (Random Survival Forest Variable Importance) and model-agnostic methods (SHapley Additive exPlanation (SHAP) and Temporal Importance Model Explanation (TIME)) in cardiovascular risk prediction using the top-performing models.

RESULTS

In a cohort of 3539 participants, longitudinal information from 35 variables that were repeatedly collected in 6 exam visits over 15 years improved subsequent long-term (17 years after) risk prediction by up to 8.3% in C-index compared to using baseline data (0.78 vs. 0.72), and up to approximately 4% compared to using the last observed CS data (0.75). Time-varying AUC was also higher in models using longitudinal data (0.86-0.87 at 5 years, 0.79-0.81 at 10 years) than using baseline or last observed CS data (0.80-0.86 at 5 years, 0.73-0.77 at 10 years). Comparative model interpretability analysis revealed the impact of longitudinal variables on model prediction on both the individual and global scales among different modeling strategies, as well as identifying the best time windows and best timing within that window for event prediction. The best strategy to incorporate longitudinal data for accuracy was time series massive feature extraction, and the easiest interpretable strategy was trajectory clustering.

CONCLUSION

Our analysis demonstrates the added value of longitudinal data in predictive accuracy and epidemiological utility in cardiovascular risk survival analysis in young adults via a unified, scalable framework that compares model performance and explainability. The framework can be extended to a larger number of variables and other longitudinal modeling methods.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT00005130, Registration Date: 26/05/2000.

Treatment of Primary Biliary Cholangitis: First-Line and Second-Line Therapies

Primary biliary cholangitis (PBC) is an autoimmune disease of the interlobular bile ducts leading to secondary damage of hepatocytes and may progress to cirrhosis and liver failure. The first-line treatment is ursodeoxycholic acid; up to 40% of patients do not have an adequate response and remain at risk of disease progression. Obeticholic acid has been conditionally approved for the treatment of PBC as add-on therapy and bezafibrate has shown similar efficacy in this group of patients. Several new therapies are in development and may further add to the treatment options available to patients with PBC.

Harnessing repeated measurements of predictor variables for clinical risk prediction: a review of existing methods

BACKGROUND

Clinical prediction models (CPMs) predict the risk of health outcomes for individual patients. The majority of existing CPMs only harness cross-sectional patient information. Incorporating repeated measurements, such as those stored in electronic health records, into CPMs may provide an opportunity to enhance their performance. However, the number and complexity of methodological approaches available could make it difficult for researchers to explore this opportunity. Our objective was to review the literature and summarise existing approaches for harnessing repeated measurements of predictor variables in CPMs, primarily to make this field more accessible for applied researchers.

METHODS

MEDLINE, Embase and Web of Science were searched for articles reporting the development of a multivariable CPM for individual-level prediction of future binary or time-to-event outcomes and modelling repeated measurements of at least one predictor. Information was extracted on the following: the methodology used, its specific aim, reported advantages and limitations, and software available to apply the method.

RESULTS

The search revealed 217 relevant articles. Seven methodological frameworks were identified: time-dependent covariate modelling, generalised estimating equations, landmark analysis, two-stage modelling, joint-modelling, trajectory classification and machine learning. Each of these frameworks satisfies at least one of three aims: to better represent the predictor-outcome relationship over time, to infer a covariate value at a pre-specified time and to account for the effect of covariate change.

CONCLUSIONS

The applicability of identified methods depends on the motivation for including longitudinal information and the method's compatibility with the clinical context and available patient data, for both model development and risk estimation in practice.

Early Prognostic Utility of Gp210 Antibody-Positive Rate in Primary Biliary Cholangitis: A Meta-Analysis

Background

The prevalence of primary biliary cholangitis (PBC), which is an autoimmune liver disease, has increased over time. PBC often leads to severe consequences, such as liver failure and death. Stratification tools using biochemical liver tests are needed to assess and predict the progression of this disease at the time of PBC diagnosis.

Methods

We searched PubMed, Cochrane Library, Web of Science, and Embase for studies focused on the relationship between positive rates of Gp210 antibodies and poor prognosis of PBC. The primary end point was the number of PBC patients with poor outcome in the Gp210 antibody (+) and Gp210 antibody (-) groups. The secondary end point was the basic serum level of alanine aminotransferase (ALT), alkaline phosphatase (ALP), total bilirubin (TBIL), and IgM in the two groups. The age and number of female patients were also measured.

Results

A total of 5 studies, comprising 737 patients, were included in this analysis. A positive rate of Gp210 antibodies was positively correlated with poor outcomes and with many types of progression in PBC, especially liver failure. Mortality was also higher in the Gp210 antibody (+) group. Furthermore, the serum levels of ALP and IgM were associated with the positive rate of Gp210 antibodies, while the serum levels of ALT and TBIL were not. The age and number of female patients were also not associated with the positive rate of Gp210 antibodies.

Conclusion

PBC-specific Gp120 antibodies are optimal predictors of PBC prognosis at the time of diagnosis. Some other liver function indicators, such as ALP and IgM, can be used as predictors to complement Gp210 antibodies to establish a stratification tool to predict the prognosis of PBC at the time of diagnosis.

A Tutorial on Evaluating the Time-Varying Discrimination Accuracy of Survival Models Used in Dynamic Decision Making

Many medical decisions involve the use of dynamic information collected on individual patients toward predicting likely transitions in their future health status. If accurate predictions are developed, then a prognostic model can identify patients at greatest risk for future adverse events and may be used clinically to define populations appropriate for targeted intervention. In practice, a prognostic model is often used to guide decisions at multiple time points over the course of disease, and classification performance (i.e., sensitivity and specificity) for distinguishing high-risk v. low-risk individuals may vary over time as an individual's disease status and prognostic information change. In this tutorial, we detail contemporary statistical methods that can characterize the time-varying accuracy of prognostic survival models when used for dynamic decision making. Although statistical methods for evaluating prognostic models with simple binary outcomes are well established, methods appropriate for survival outcomes are less well known and require time-dependent extensions of sensitivity and specificity to fully characterize longitudinal biomarkers or models. The methods we review are particularly important in that they allow for appropriate handling of censored outcomes commonly encountered with event time data. We highlight the importance of determining whether clinical interest is in predicting cumulative (or prevalent) cases over a fixed future time interval v. predicting incident cases over a range of follow-up times and whether patient information is static or updated over time. We discuss implementation of time-dependent receiver operating characteristic approaches using relevant R statistical software packages. The statistical summaries are illustrated using a liver prognostic model to guide transplantation in primary biliary cirrhosis.

Natural History of Primary Biliary Cholangitis in the Ursodeoxycholic Acid Era: Role of Scoring Systems

Primary biliary cholangitis (PBC) is a chronic disease that progresses to end-stage liver disease. Ursodeoxycholic acid (UDCA), the standard treatment for PBC for several decades, is associated with improved survival without liver transplantation. Approximately 40% of patients do not respond to UDCA. Because of disease variability, several prognostic models exist that incorporate various factors including biochemical response to UDCA. Useful for patient care and counseling as well as risk stratification for research and clinical trials, the role of these models in the pre-UDCA and UDCA eras is discussed.

Current Treatment Options for Primary Biliary Cholangitis

Primary biliary cholangitis is a progressive, autoimmune disease of the interlobular bile ducts, leading to secondary damage of hepatocytes that may progress to cirrhosis and liver failure. Until recently, the only approved treatment was ursodeoxycholic acid. However, 40% of patients do not have an adequate response. Obeticholic acid was approved for treatment as add-on therapy in this group of patients. Off-label use of fibrates has also been reported to be effective. Several new therapies are in development and may further add to the treatment options available to patients with primary biliary cholangitis.

Risk stratification and prognostic modelling in primary biliary cholangitis

Primary biliary cholangitis (PBC) is a slowly progressive chronic cholestatic liver disease that, in a subgroup of patients, may result in liver failure or death. The definition of specific risk profiles, i.e. risk stratification, is of critical importance for the identification of these subgroups and thereby the targeting of care. Over the last few years large multicentre cohort studies have improved our knowledge regarding factors associated with progressive disease. Stratification based on biochemical response to ursodoxycholic acid provides a readily available measure to identify groups that might benefit from additional therapies to further improve prognosis. In addition, serum total bilirubin and alkaline phosphatase are now considered the most robustly validated biomarkers of long-term outcome in PBC and are used as endpoints in clinical trials. The GLOBE score and UK-PBC risk score enable us to quantify the risk of future events for the individual patient, allowing more individualized risk prediction. In this review, we discuss both established prognostic factors and newly developed tools to estimate prognosis in PBC, highlighting their strengths, limitations and applicability in clinical practice.

An Update on the Treatment and Follow-up of Patients with Primary Biliary Cholangitis

Primary biliary cholangitis (PBC) is an autoimmune liver disease characterized by chronic granulomatous lymphocytic cholangitis of the small bile ducts. PBC was a leading indication for liver transplant in the United States; with early diagnosis and treatment, the majority of patients with PBC have a normal life expectancy. Pathogenesis involves inflammatory damage of bile duct epithelium secondary to innate and adaptive immune responses, and toxicity from accumulated bile acids. Cholestasis and disease progression can lead to cirrhosis. Extrahepatic complications include dyslipidemia, metabolic bone disease, and fat-soluble vitamin deficiency. Ursodeoxycholic acid is a well-established therapy. Novel targeted therapeutics are being developed.

The value of daily platelet counts for predicting dengue shock syndrome: Results from a prospective observational study of 2301 Vietnamese children with dengue

BACKGROUND

Dengue is the most important mosquito-borne viral infection to affect humans. Although it usually manifests as a self-limited febrile illness, complications may occur as the fever subsides. A systemic vascular leak syndrome that sometimes progresses to life-threatening hypovolaemic shock is the most serious complication seen in children, typically accompanied by haemoconcentration and thrombocytopenia. Robust evidence on risk factors, especially features present early in the illness course, for progression to dengue shock syndrome (DSS) is lacking. Moreover, the potential value of incorporating serial haematocrit and platelet measurements in prediction models has never been assessed.

METHODOLOGY/PRINCIPAL FINDINGS

We analyzed data from a prospective observational study of Vietnamese children aged 5-15 years admitted with clinically suspected dengue to the Hospital for Tropical Diseases in Ho Chi Minh City between 2001 and 2009. The analysis population comprised all children with laboratory-confirmed dengue enrolled between days 1-4 of illness. Logistic regression was the main statistical model for all univariate and multivariable analyses. The prognostic value of daily haematocrit levels and platelet counts were assessed using graphs and separate regression models fitted on each day of illness. Among the 2301 children included in the analysis, 143 (6%) progressed to DSS. Significant baseline risk factors for DSS included a history of vomiting, higher temperature, a palpable liver, and a lower platelet count. Prediction models that included serial daily platelet counts demonstrated better ability to discriminate patients who developed DSS from others, than models based on enrolment information only. However inclusion of daily haematocrit values did not improve prediction of DSS.

CONCLUSIONS/SIGNIFICANCE

Daily monitoring of platelet counts is important to help identify patients at high risk of DSS. Development of dynamic prediction models that incorporate signs, symptoms, and daily laboratory measurements, could improve DSS prediction and thereby reduce the burden on health services in endemic areas.

Increased cancer risk in a large population-based cohort of patients with primary biliary cirrhosis: follow-up for up to 36 years

BACKGROUND AND AIMS

The natural history of primary biliary cirrhosis (PBC) has so far mainly been studied in tertiary referral centres. The aim of the present investigation was to describe the natural history of PBC in a large population-based cohort in order to identify risk factors for development of malignancies and disease progression.

METHODS

Four independent hospital databases were searched in 44 hospitals in a geographically defined area, after which all medical records were evaluated on site. In addition, PBC registries in the three liver transplant centers were checked for missed referrals from the area of interest.

RESULTS

In total, 992 cases fulfilled the inclusion criteria. The median follow-up was 73 months (range 0-434). Mortality was similar to the age- and gender matched population (SMR 1.1; 95 % CI 0.9-1.4). Male gender, smoking, and elevated bilirubin, decreased albumin, and elevated AST at time of diagnosis, were associated with an increased risk for the combined end point PBC-related death or liver transplantation. In total, 133 (13 %) patients developed one or more malignancies (SIR 1.5; 95 % CI 1.1-1.9). There was a ninefold increased risk of developing hepatobiliary malignancies (SIR 9.4; 95 % CI 3.04-21.8), a fivefold increased risk of developing urinary bladder cancer (SIR 5.0; 95 % CI 1.6-11.6), and a 1.8-fold increased risk of developing breast cancer (SIR 1.8; 95 % CI 1.08-2.81).

CONCLUSION

PBC is associated with an increased risk of hepatobiliary, bladder and breast cancer. Still, survival-under treatment with ursodeoxycholic acid (UDCA)-was comparable to the general population in this population-based study.

Ursodeoxycholic acid improves bilirubin but not albumin in primary biliary cirrhosis: further evidence for nonefficacy

Background/Aim. In randomised controlled trials (RCTs) of ursodeoxycholic acid (UDCA), although serum bilirubin is frequently reduced, its effect on disease progression and mortality is unclear. As serum albumin is an established independent prognostic marker, one might expect less deterioration of serum albumin values in a UDCA-treated group. We therefore modelled the typical evolution of serum bilirubin and albumin levels over time in UDCA-untreated patients and compared it with the observed levels in UDCA RCTs. Methods. Multilevel modelling was used to relate the evolution of serum albumin to serum bilirubin and time since patient referral. For each considered RCT, the derived model was used to predict the relationship between final mean serum albumin and bilirubin concentration, adjusted for mean serum albumin at referral and followup duration. Results. Five RCTs were eligible in terms of available data, of which two had long followup. In all trials, serum albumin did not significantly differ between UDCA- and placebo-treated patients, despite the UDCA effect on serum bilirubin. Therefore, there is no evidence over time for changes or maintenance of albumin levels for UDCA-treated patients above the levels predicted for placebo-treated patients. Conclusions. Our findings suggest that UDCA does not alter serum albumin in a way that is consistent with its effect on serum bilirubin. Therefore, reductions in serum bilirubin of UDCA-treated PBC do not parallel another validated and independent prognostic marker, further questioning the validity of serum bilirubin reduction with UDCA as a surrogate therapeutic marker.

Chronic kidney disease after liver transplantation: pretransplantation risk factors and predictors during follow-up

BACKGROUND

Chronic renal impairment is an emerging problem in the management of patients after liver transplantation (LT).

METHODS

We prospectively analyzed predictors of chronic kidney disease (CKD) after LT in 179 patients followed for a median of 63 months. Diagnosis of CKD was based on an estimated glomerular filtration rate (GFR) of less than 60 mL/min according to the current position statement from the Kidney Disease Improving Global Outcome. Pretransplantation risk factors were evaluated. A Cox regression analysis, with time-dependent variables evaluated during follow-up, was applied to realize a prognostic model for CKD, and a prognostic index was also calculated. The validity of the model was tested in 149 independent LT patients with a median follow-up of 46 months.

RESULTS

The cumulative incidence of CKD was 45% at 5 years after LT. Estimated GFR at LT was the only pretransplantation independent risk factor (beta, 0.33; standard error (beta), 0.07; 95% confidence interval, 0.95-0.98). Development of arterial hypertension (hazards ratio [HR], 1.83), episodes of severe infection (HR, 2.15), and estimated GFR (HR, 0.89) after LT were identified as independent prognostic factors at the Cox regression time-dependent analysis. The model was able to identify the patients at higher risk for the development of CKD in the validation set.

CONCLUSIONS

Lower renal function at transplantation is associated with a higher risk of CKD after transplantation. A predictive model based on the variation of posttransplantation variables during the course of follow-up can help the clinicians to estimate the probability of CKD in the next 12 months.

Analysis of heart transplant survival data using generalized additive models

The Stanford Heart Transplant data were collected to model survival in patients using penalized smoothing splines for covariates whose values change over the course of the study. The basic idea of the present study is to use a logistic regression model and a generalized additive model with B-splines to estimate the survival function. We model survival time as a function of patient covariates and transplant status and compare the results obtained using smoothing spline, partial logistic, Cox's proportional hazards, and piecewise exponential models.

The clinical course of alcoholic cirrhosis: effects of hepatic metabolic capacity, alcohol consumption, and hyponatremia--a historical cohort study

Background

The cirrhosis complications hepatic encephalopathy, ascites, and variceal bleeding increase mortality but develop in random sequence. Therefore prognoses based on the presence or absence of these clinical complications are inherently inaccurate, and other determinants of the clinical course should be identified. Here we present our study of patho-etiological factors that may be causally involved in the development of specific complications to alcoholic cirrhosis; it was based on a model of cirrhosis pathophysiology encompassing hepatic metabolic capacity, continued alcohol consumption, and circulatory dysfunction.

Methods

We followed a Danish community-based cohort of 466 patients with alcoholic cirrhosis. Stratified Cox regression was used to examine the effects of GEC (a measure of hepatic metabolic capacity), alcohol consumption, and plasma sodium concentration (a measure of circulatory dysfunction) on the hazard rates of first-time hepatic encephalopathy, first-time ascites, first-time variceal bleeding, and mortality. We adjusted for confounding by comorbidity, gender, and age. Data on risk factors and confounders were updated during follow-up.

Results

A low GEC increased the risk of first-time hepatic encephalopathy (hazard ratio [HR] 1.21 per 0.1 mmol/min GEC loss, 95% CI 1.11-1.31), but was unassociated with other adverse events. Alcohol consumption increased the risk of first-time ascites (HR 3.18, 95% CI 1.19-8.47), first-time variceal bleeding (HR 2.78, 95% CI 1.59-4.87), and mortality (HR 2.45, 95% CI 1.63-3.66), but not the risk of first-time hepatic encephalopathy. Hyponatremia increased the risk of all adverse events.

Conclusions

Reduced hepatic metabolic capacity, alcohol consumption, and hyponatremia were causally involved in the development of specific complications to alcoholic cirrhosis.

Survival data analysis with time-dependent covariates using generalized additive models

We discuss a flexible method for modeling survival data using penalized smoothing splines when the values of covariates change for the duration of the study. The Cox proportional hazards model has been widely used for the analysis of treatment and prognostic effects with censored survival data. However, a number of theoretical problems with respect to the baseline survival function remain unsolved. We use the generalized additive models (GAMs) with B splines to estimate the survival function and select the optimum smoothing parameters based on a variant multifold cross-validation (CV) method. The methods are compared with the generalized cross-validation (GCV) method using data from a long-term study of patients with primary biliary cirrhosis (PBC).

Predicting the advent of ascites and other complications in primary biliary cirrhosis: a staged model approach

BACKGROUND

Current survival models for primary biliary cirrhosis have limited precision for medium and long-term survival. Aim To describe a prognostic model for the advent of complications in primary biliary cirrhosis as the first approach to a staged prognostic model.

METHODS

From an established database of 289 consecutive primary biliary cirrhosis patients referred to Royal Free Hospital over 12 years (mean follow-up of 4.1 years), baseline characteristics at referral were evaluated by Cox-proportional hazards regression modelling.

RESULTS

The following complications occurred de novo: 85 ascites/peripheral oedema, 40 oesophagogastric varices, 63 encephalopathy, 29 spontaneous bacterial peritonitis and/or septicaemia, 59 symptomatic urinary tract infections. Age, albumin, log(10)(bilirubin), presence of ascites at referral, variceal bleeding within 6 weeks before referral, detection of oesophagogastric varices at or before referral were significant at multivariate analysis with different combinations and coefficients for each complication. The model for predicting ascites and/or peripheral oedema best fitted the observed data (ROC = 0.7682, S.E. = 0.0385).

CONCLUSIONS

The known prognostic factors in primary biliary cirrhosis also model the advent of complications. In view of the prognostic importance of ascites and its more robust statistical model, ascites and/or peripheral oedema could represent, following validation, the most suitable staged model in primary biliary cirrhosis to improve precision in survival modelling.

Variceal bleeding in primary biliary cirrhosis patients: a subgroup with improved prognosis and a model to predict survival after first bleeding

BACKGROUND

Varices are a late complication in primary biliary cirrhosis (PBC). However, patients without clinical jaundice do bleed from varices; whether their prognosis differs is unknown.

AIM

Evaluate PBC patients, particularly those with bilirubin <or=34 micromol/l at the time of bleeding.

PATIENTS/RESULTS

One hundred and two variceal bleeders were present (median, follow-up 20.5 months, range 0-180), who at diagnosis had: pruritus (51%), fatigue (32%) and 23 (22.5%) variceal bleeding. Histologically advanced disease was present in 96 of 100 patients (stage 3: 14 and stage 4: 82); 83 died, 24 within 6 weeks of first bleeding. At the time of bleeding, 26 patients had bilirubin <or=34 micromol/l. In this group, 24 patients were stage 4, in 13 bleeding was the first presentation of PBC and they were older (59.4 vs. 55.4 years, P=0.09), had lower alkaline phosphatase (491.5 vs. 510, P=0.03) but similar albumin values, surviving a median 61 versus 12 months, compared with the 76 patients with bilirubin >34 micromol/l (P=0.001, log rank test). Hazard ratios (95% confidence intervals) for independent predictors of mortality after bleeding were: age 1.02 (1-1.05), log10 bilirubin 4.64 (2.56-8.41), ascites 2.13 (1.29-3.51) and hepatic encephalopathy 2.72 (1.56-4.74).

CONCLUSION

Variceal bleeding complicates histologically advanced PBC. A distinct subgroup with near normal bilirubin and lower alkaline phosphatase first presents with variceal bleeding in 50% of cases and has a better prognosis than jaundiced PBC variceal bleeders.

[Natural history of primary biliary cirrhosis]

Primary biliary cirrhosis is a chronic cholestatic disease that generally appears in middle-aged women. The clinical course is slow and progressive, finally leading to cirrhosis. This disease has three forms of presentation: silent, asymptomatic and symptomatic. The silent form is characterized by the presence of antimitochondrial antibodies as the only abnormality. The silent and asymptomatic forms are less aggressive and have a slower clinical course. During the course of the disease, some patients remain asymptomatic. No distinguishing features between asymptomatic patients and those who develop symptoms have been identified. Survival is better in asymptomatic than in symptomatic patients and is excellent in patients who remain asymptomatic. The introduction of treatment with ursodeoxycholic acid has greatly prolonged the natural course of the disease. In patients with good therapeutic response, survival is similar to that in the general population. The clinical and laboratory variables associated with poor prognosis are age, bilirubinemia, albuminemia, prothrombin time, ascites, hepatic encephalopathy and advanced histological stage. Likewise, the development of varices and of hepatocellular carcinoma carries a poor prognosis. Bilirubinemia is, however, the most important variable to establish prognosis. There are distinct mathematical prognostic models that sensitively predict the probability of survival and are useful to determine disease severity in specific patients.

Liver/spleen volume ratio as a predictor of prognosis in primary biliary cirrhosis

BACKGROUND

The course of primary biliary cirrhosis (PBC) is determined by clinical symptoms and histological findings. The present study examined the prognostic importance of imaging parameters in PBC.

METHODS

The volumes of the liver and spleen of patients with PBC were assessed by computed tomography (CT). The volume ratio of liver to spleen (LV/SV ratio) was evaluated and used for further analyses.

RESULTS

The prognosis was significantly poorer in PBC patients with a low, rather than high, LV/SV ratio. The Cox proportional hazard regression model showed that the serum bilirubin level and the LV/SV ratio could predict the prognosis of PBC patients. In addition, the LV/SV ratio was significantly lower in patients who developed symptoms (s-PBC) than in those who remained asymptomatic (a-PBC) during the observation period.

CONCLUSIONS

The LV/SV ratio is of prognostic importance in patients with PBC.

Antimitochondrial antibody-negative primary biliary cirrhosis

There is a subset of patients who have biochemical and histologic features consistent with primary biliary cirrhosis (PBC) who lack antimitochondrial antibodies (AMA). This entity is usually referred to as AMA-negative PBC or alternatively autoimmune cholangitis. Patients who have AMA-negative PBC are believed to have a similar clinical course, response to treatment, and prognosis as their AMA-positive counterparts. As more sensitive and specific serologic tests are developed to detect serum AMA, it is possible we may find that these patients initially believed to be AMA-negative are indeed AMA-positive, suggesting a single disease process.

Azathioprine for primary biliary cirrhosis

BACKGROUND

Azathioprine is used for patients with primary biliary cirrhosis, but the therapeutic responses in randomised clinical trials have been conflicting.

OBJECTIVES

To assess the benefits and harms of azathioprine for patients with primary biliary cirrhosis.

SEARCH STRATEGY

Randomised clinical trials were identified by searching The Cochrane Hepato-Biliary Group Controlled Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, MEDLINE, EMBASE, Science Citation Index Expanded, The Chinese Biomedical Database, and LILACS, and manual searches of bibliographies to September 2005.

SELECTION CRITERIA

Randomised clinical trials comparing azathioprine versus placebo, no intervention, or another drug were included irrespective of blinding, language, year of publication, and publication status.

DATA COLLECTION AND ANALYSIS

Our primary outcomes were mortality, and mortality or liver transplantation. Dichotomous outcomes were reported as relative risk (RR) with 95% confidence interval (CI). Continuous outcomes were reported as weighted mean difference (WMD) or standardised mean difference (SMD). We examined the intervention effects by random-effects and fixed-effect models.

MAIN RESULTS

We identified two randomised clinical trials with 293 patients. Only one of the trials was regarded as having low bias risk. Azathioprine did not significantly decrease mortality (RR 0.80, 95% CI 0.49 to 1.31, 2 trials). Azathioprine did not improve pruritus at one-year intervention (RR 0.71, 95% CI 0.28 to 1.84, 1 trial), cirrhosis development, or quality of life. Patients given azathioprine experienced significantly more adverse events than patients given no intervention or placebo (RR 2.44, 95% CI 1.14 to 5.20, 2 trials). The common adverse events were rash, severe diarrhoea, and bone marrow depression.

AUTHORS' CONCLUSIONS

There is no evidence to support the use of azathioprine for patients with primary biliary cirrhosis. Researchers who are interested in performing further randomised clinical trials should be aware of the risks of adverse events.

Prognosis of ursodeoxycholic Acid-treated patients with primary biliary cirrhosis. Results of a 10-yr cohort study involving 297 patients

BACKGROUND AND AIMS

The therapeutic potential of ursodeoxycholic acid (UDCA) treatment in primary biliary cirrhosis (PBC) remains controversial. In addition, relatively few data have been reported on the outcome of patients who have been treated long term. The aim of the present study was to document long-term survival of a prospectively followed large cohort of UDCA treated patients in comparison to that predicted by the Mayo model and of a matched control cohort of the Dutch population.

METHODS

Two hundred ninety-seven patients were included and followed during a median period of 68 (range 3-126) months until death or the end of the study.

RESULTS

Survival free of transplantation (1 yr 99.7%, 5 yr 87%, and 10 yr 71%) was significantly better than predicted by the Mayo model (p= 0.01). However, for patients with abnormal serum bilirubin and/or albumin concentrations at entry, observed and predicted survival did not significantly differ. Compared with survival for a standardized cohort of the Dutch population, observed survival for the total group was significantly decreased (p= 0.0003); for noncirrhotic patients and patients with normal entry bilirubin and albumin concentrations survival was comparable. Serum bilirubin and albumin concentrations were the prognostic factors most consistently associated with survival.

CONCLUSIONS

A 10-year prognosis for most UDCA-treated patients with PBC, i.e., those with a normal bilirubin and albumin concentration, is comparable to that of a matched general population. Our finding that observed survival was significantly better than predicted by the Mayo model may suggest that this model did not accurately predict prognosis in our cohort. Alternatively, this finding indicates an important therapeutic effect of long-term UDCA treatment in PBC, particularly in patients with noncirrhotic, nonadvanced disease.

The AST/ALT ratio as an indicator of cirrhosis in patients with PBC

OBJECTIVES

A non-invasive, simple and non-expensive test to predict cirrhosis would be highly desirable. The aspartate aminotransferase/alanine aminotransferase (AST/ALT) ratio has been proven to be such an indicator of cirrhosis in alcoholic liver disease, hepatitis C.

AIM

To test whether the AST/ALT ratio is a marker of cirrhosis also in patients with primary biliary cirrhosis (PBC).

METHODS

The study consisted of 160 patients. In 126 patients, we had clinical and laboratory data at the time of diagnosis and follow-up with outcome: liver-related death, liver transplantation and survival. In 121 patients, we had laboratory data and liver histology.

RESULTS

We found that the AST/ALT ratio was significantly higher in cirrhotic patients than in non-cirrhotic patients. A high AST/ALT ratio was significantly associated with esophageal varices and ascites. In a multivariate analysis, bilirubin and ALP were predictors of poor prognosis.

CONCLUSION

The AST/ALT ratio seems to be of clinical value as a hint to the diagnosis of cirrhosis in patients with PBC but not as a prognostic factor.

An Economic Evaluation of Pediatric Small Bowel Transplantation in the United Kingdom

BACKGROUND

Small bowel transplantation (SBTx) offers an alternative to parenteral nutrition (PN) for the treatment of chronic intestinal failure in children: this study estimated its cost-effectiveness in the early phase of a U.K. program.

METHODS

Children assessed for SBTx were categorized as: 1) requiring SBTx following PN-related complications (n=23), 2) stable at home not requiring SBTx (n=24), and 3) terminally ill and unsuitable for SBTx (n=6). Costs were estimated from detailed resource-use data. Two comparisons were used for effectiveness: actual survival following transplantation (n=14) compared to: 1) estimated survival without transplantation using a prognostic model, and 2) the waiting list experiences of all patients listed for SBTx (n=23).

RESULTS

Mean costs up to 30 months were pounds sterling 207,000 for those transplanted or on the waiting list, pounds sterling 159,000 for those stable on home PN, and pounds sterling 56,000 for those terminally ill. The prognostic model estimated a mean survival gain from transplantation of 0.12 years over 30 months, and suggested that transplantation was cost-saving. The second approach suggested that transplantation reduced survival by 0.24 years at an additional cost of pounds sterling 131,000.

CONCLUSIONS

Firm conclusions on cost-effectiveness of SBTx are not possible given the two different estimates. The prognostic model approach (suggesting that pediatric SBTx may provide a small survival benefit at a small reduction in costs) should be less subject to bias, but the model requires external validation. Meanwhile, children at risk of fatal PN-complications should be given the opportunity to receive a SBTx only within a continuing formal assessment of the technology.

Occurrence of cirrhosis-related complications is a time-dependent prognostic predictor independent of baseline model for end-stage liver disease score

BACKGROUND

The model for end-stage liver disease (MELD) is used to prioritize cirrhotic patients awaiting liver transplantation. Many cirrhosis-related complications are indications for transplantation but are not included in MELD. This study investigated the impact of these complications on survival and association with MELD.

METHODS

The mortality risk of cirrhosis-related complications, including bleeding esophageal varices, spontaneous bacterial peritonitis, hepatic encephalopathy, hepatorenal syndrome and hepatic decompensation, was analyzed using a time-dependent Cox regression model in 227 cirrhotic patients.

RESULTS

A total of 281 episodes of complications occurred in 142 (63%) patients. Patients who died had a significantly higher baseline MELD score compared with those who survived (14.5 +/- 4.5 vs 12.8 +/- 3.9, P = 0.004). There was no significant difference in the MELD score between patients with and without the occurrence of complications (13.6 +/- 4.3 vs 12.9 +/- 4.0, P = 0.093). Patients with a higher baseline MELD score tended to develop early complications (rho = -0.598, P< 0.001). Using the Cox regression model, the risk ratio of mortality was 4.9 (95% confidence interval: 3.9-6.3, P< 0.0001) for each additional episode of complication.

CONCLUSIONS

The mortality risk increases as the number of complication episodes increases. While patients with repeated complications have a poor outcome, they do not necessarily have a higher baseline MELD score and could be down-staged in the MELD era.

Persistent normalization of serum alanine aminotransferase levels improves the prognosis of type 1 autoimmune hepatitis

BACKGROUND/AIMS

Autoimmune hepatitis shows a good response to immunosuppressive treatment, and the prognosis may be determined by the clinical course. The present study was conducted in order to analyze the factors contributing to the outcomes of patients with type 1 autoimmune hepatitis.

METHODS

Eighty-four consecutive patients with type 1 autoimmune hepatitis were followed up regularly for a median follow-up period of 70.5 months (16.2-163 months). We analyzed the prognostic factors using time-fixed and time-dependent Cox proportional hazard models. The end point was progression of the disease to decompensated liver cirrhosis.

RESULTS

Seventy-seven patients (92%) were treated with prednisolone during the follow-up period, and 11 patients (13%) developed decompensated liver cirrhosis. Using a time-dependent multivariate model, the starting dose of corticosteroid (dose of prednisolone <20 mg/day), relapse within 3 months after the normalization of serum alanine aminotransferase levels with initial treatment, and elevated serum alanine aminotransferase levels during the follow-up period (>40 IU/L), all showed a significant association with progression of the disease.

CONCLUSIONS

The prognosis of type 1 autoimmune hepatitis on adequate immunosuppressive treatment improves when the serum alanine aminotransferase level persists at < or = 40 IU/L. Factors existing prior to medical treatment may not affect the prognosis.

Survival following the development of ascites and/or peripheral oedema in primary biliary cirrhosis: a staged prognostic model

OBJECTIVE

Current prognostic models in primary biliary cirrhosis (PBC) have low precision, partly due to the restricted inclusion criteria of some cohorts used for modelling but also because of the prolonged natural course of the disease. It is hypothesized that better precision could be achieved with a staged model, using ascites or peripheral oedema as a new starting-point for prediction.

MATERIAL AND METHODS

The study was based on an established database of 289 consecutive patients, followed between 1977 and 1998. Stepwise Cox regression was used to construct a staged model based on 143 patients who first developed ascites (n=111) or peripheral oedema (n=32) at entry or during subsequent follow-up. The model was compared with published models using graphical methods and receiver operating characteristics (ROCs).

RESULTS

Mean time from clinical diagnosis of ascites or peripheral oedema to death was 3.1 years. The following variables had independent prognostic significance: log10(bilirubin) (p<0.001), albumin (p<0.001), age (p<0.001) and history of encephalopathy (p<0.001). Goodness of fit showed that the survival probabilities predicted by the Ascites Stage Model fitted well with the observed data. The Ascites Stage Model (ROC 0.8324 (SE 0.0348)) was a better predictor of survival than the Mayo long-term model (ROC 0.7833 (SE 0.0397)), the Mayo Repeated Patient Visits Model (ROC 0.7779 (SE 0.0399)) and the Royal Free PBC Prognostic Model (ROC 0.7785 (SE 0.0396)).

CONCLUSIONS

The Ascites Stage Model gives a better survival estimate for PBC patients once they have developed ascites or peripheral oedema compared with the current models, and demonstrates an advantage of staged models in diseases with a prolonged natural history.

The effect of ursodeoxycholic acid therapy on the natural course of primary biliary cirrhosis

BACKGROUND AND AIMS

We used a multistate modeling approach to assess the effect of ursodeoxycholic acid (UDCA) therapy on the natural course of primary biliary cirrhosis (PBC), which remains controversial.

METHODS

Our population included 262 patients with PBC who had received 13-15 mg/kg UDCA daily for a mean of 8 years (range, 1-22 years). Data were analyzed using a multistate Markov model, with histologic stage progression, death, and orthotopic liver transplantation (OLT) as main end points. Survival without OLT was compared with that predicted by the updated Mayo model and with the expected survival in the control population.

RESULTS

Forty-five patients developed cirrhosis, 20 underwent OLT, and 16 died by the censor date. Ten deaths were due to liver disease. The overall survival rates were 92% at 10 years and 82% at 20 years. Survival rates without OLT were 84% and 66% at 10 and 20 years, respectively, which were slightly lower than the survival rate of an age- and sex-matched control population (relative risk [RR], 1.4; P = .1) but better than the spontaneous survival rate as predicted by the updated Mayo model (RR, .5; P < .01). The survival rate of patients in stage 1 and 2 was similar to that in the control population (RR, .8; P = .5), whereas the probability of death or OLT remained significantly increased in treated patients in late histologic stages (RR, 2.2; P < .05).

CONCLUSIONS

Treatment with UDCA alone normalizes the survival rate of patients with PBC when given at early stages. However, there is a continued need for new therapeutic options in patients with advanced disease.

The importance of accounting for the uncertainty of published prognostic model estimates

OBJECTIVES

Reported is the importance of properly reflecting uncertainty associated with prognostic model estimates when calculating the survival benefit of a treatment or technology, using liver transplantation as an example.

METHODS

Monte Carlo simulation techniques were used to account for the uncertainty of prognostic model estimates using the standard errors of the regression coefficients and their correlations. These methods were applied to patients with primary biliary cirrhosis undergoing liver transplantation using a prognostic model from a historic cohort who did not undergo transplantation. The survival gain over 4 years from transplantation was estimated.

RESULTS

Ignoring the uncertainty in the prognostic model, the estimated survival benefit of liver transplantation was 16.7 months (95 percent confidence interval [CI], 13.5 to 20.1), and was statistically significant (p < .001). After adjusting for model uncertainty using the standard errors of the regression coefficients, the estimated survival benefit was 17.5 months (95 percent CI, -3.9 to 38.5) and was no longer statistically significant. An additional adjustment for the correlation between regression coefficients widened the 95 percent confidence interval slightly: the estimated survival benefit was 17.0 months (95 percent CI: -4.6 to 38.6).

CONCLUSIONS

It is important that the precision of regression coefficients is available for users of published prognostic models. Ignoring this additional information substantially underestimates uncertainty, which can then impact misleadingly on policy decisions.

Midterm cost-effectiveness of the liver transplantation program of England and Wales for three disease groups

Liver transplantation has never been the subject of a randomized controlled trial, and there remains uncertainty about the magnitude of benefit and cost-effectiveness for specific patient groups. This article reports the results of an economic evaluation of adult liver transplantation in England and Wales. Patients placed on the waiting list for a liver transplant were observed over 27 months. The costs and health benefits of a comparison group, representing experience in the absence of liver transplantation, were estimated using a combination of observed data from patients waiting for a transplant and published prognostic models. The analysis focuses on three disease groups, for each of which prognostic models were available: primary biliary cirrhosis (PBC), alcoholic liver disease (ALD), and primary sclerosing cholangitis (PSC). A higher proportion of patients with ALD were assessed for a transplant but not placed on the waiting list. The estimated gain in quality-adjusted life-years from transplantation was positive for each of the disease groups. The mean incremental cost per quality-adjusted life-year (95% bootstrap confidence intervals) from time of listing to 27 months for patients with PBC, ALD, and PSC are pound 29,000 (pounds 1,000 to pounds 59,000), pounds 48,000 (pounds 12,000 to pounds 83,000) and pounds 21,000 (-pounds 23,000 to pounds 60,000), respectively. In conclusion, liver transplantation increases the survival and health-related quality of life of patients with each of three end-stage liver diseases. However, the extent of this increase differs between different disease groups. Cost-effectiveness estimates were poorer for patients with ALD over the 27-month period than for patients with PBC or PSC. This in part reflects the costs of the higher number of ALD patients assessed for each transplant.

Liver transplantation for primary biliary cirrhosis

Liver transplantation is the accepted treatment for patients with end-stage liver disease or intractable symptoms secondary to primary biliary cirrhosis (PBC), and has proven survival benefit. Indications for transplantation are an unacceptable quality of life or anticipated death in less than 1 year. Although there are a number of prognostic models, serum bilirubin provides the simplest guide to transplantation timing. Those grafted for PBC are at greater risk of developing chronic rejection, and are less likely to be successfully weaned from immunosuppression than those grafted for other indications. Following transplantation, antimitochondrial antibodies persist and histological features of recurrent PBC may be seen in the allograft in up to 50% by 10 years; however, at least in the medium-term, this rarely causes clinical problems.

Natural history of primary biliary cirrhosis

The natural history of PBC is characterized by slowly progressive cholestasis with liver damage, development of cirrhosis and its complications, and death, unless the patient undergoes liver transplantation. The disease has at least three clinical presentations, each with a different course and prognosis: the silent and usually less aggressive form, the asymptomatic form, and the symptomatic form. There are no identifiable features that distinguish the asymptomatic population who will remain symptom-free from those patients who will develop symptoms. As expected, the survival is longer in asymptomatic than in symptomatic patients. Overall survival of asymptomatic PBC is shorter than for an age- and gender-matched control population, but the patients remaining asymptomatic had a survival equal to that of the general population. Natural history studies have identified several variables associated with survival, particularly age, bilirubin, albumin, prothrombin time, ascites, encephalopathy, and advanced histological stage. Development of esophageal varices and hepatocellular carcinoma can also affect survival. Serum bilirubin level is, however, the most heavily weighted prognostic variable and can be used as a simplistic prognostic index for patients with PBC. In the last two decades, natural history models have been developed that include clinical, biochemical, and histological variables, the most popular being the Mayo model. It has the advantage ofavoiding histological variables, and therefore can be applicable to a broad spectrum of patients with PBC. The models may also be used to evaluate the efficacy of different new treatments. Prognostic models based on serial measurements of the independent predictors of poor prognosis would lead to a more accurate prediction of survival; however, they probably will not replace clinical outlook.

Liver transplantation for primary sclerosing cholangitis in the Nordic countries: outcome after acceptance to the waiting list

Primary sclerosing cholangitis (PSC) is a common indication for liver transplantation, but evaluation of patients and timing of liver transplantation remain as major problems. Data from PSC and control patients listed for liver transplantation from 1990 through 2000 in the Nordic countries were recorded prospectively. Outcomes from the waiting list and after transplantation have been recorded for both groups. For PSC patients, regression analyses have been performed to analyze predictors of outcome. A total of 255 PSC and 610 control patients were accepted on the liver transplantation waiting list from 1990 to 2000. In the PSC group, 223 patients (87%) received a first liver allograft, and 32 patients (13%) died without transplantation. The corresponding figures for the control group were 89% and 10%. For PSC patients, the 5- and 10-year survival from the time of acceptance was 68% and 58%, respectively. A higher Model for End-Stage Liver Disease score and a shorter duration of PSC predicted death on the waiting list for PSC patients. PSC is a frequent indication for liver transplantation. In our material, serum bilirubin or Model for End-Stage Liver Disease score and PSC duration are predictors of outcome including survival of the waiting list.

Survival and symptom progression in a geographically based cohort of patients with primary biliary cirrhosis: follow-up for up to 28 years

BACKGROUND & AIMS

Although several excellent studies have described the natural history of primary biliary cirrhosis, most were reported from tertiary referral centers. We examined the prognosis of primary biliary cirrhosis in a comprehensive geographically defined cohort.

METHODS

We followed up 770 primary biliary cirrhosis patients prevalent between January 1987 and December 1994 until death, transplantation, or censor on January 1, 2000, by interview and review of case notes and death certificates. Analysis of survival data was performed with Kaplan-Meier methods and Cox regression.

RESULTS

Median patient survival was 9.3 years from diagnosis. Patient age, alkaline phosphatase, albumin, and bilirubin at diagnosis independently predicted survival in Cox modeling. Prothrombin time and histologic stage did not independently affect survival. Observed survival was predicted well by this model and by the Mayo prognostic score (R2(M) = 0.37 and 0.18, respectively; R2(M) is a likelihood-based measure of the percentage information gain from the model due to covariates). Forty-two percent of deaths were caused by liver disease. Thirty-nine patients had liver transplantations by the censor date. Survival was much poorer than for an age- and sex-matched control population (standardized mortality ratio = 2.87 [1.73 excluding liver deaths]). The most common symptoms at diagnosis were pruritus (18.9%) and fatigue (21.0%). Twenty-six percent of patients developed liver failure by 10 years after diagnosis.

CONCLUSIONS

Although primary biliary cirrhosis is often now diagnosed at an early stage, the diagnosis still carries important prognostic implications. A significant proportion of patients develop liver failure, require transplantation, or die prematurely after this diagnosis.

Quantitative testing of liver function compared to prognostic scores in patients with primary biliary cirrhosis

AIM

Primary biliary cirrhosis (PBC) is a slowly progressive liver disease which can lead to cirrhosis. We investigated if quantitative tests of liver function (QTLF) and serum levels of a surrogate marker of hepatic fibrogenesis (PIIINP) provide information in addition to established prognostic scores.

METHODS

In 34 PBC patients PIIINP, PBC-relevant parameters, histological staging and QTLF at entry and at 2 years were determined and compared with the Christensen (CPS I, CPS II) and Mayo prognosis score. QTLF included aminopyrine breath test, galactose elimination capacity, sorbitol and indocyanine green clearance.

RESULTS

Bilirubin, serum IgM and PIIINP were elevated at both time points, whereas albumin and prothrombin time remained normal. Clinical findings (ascites, cirrhosis, central cholestasis) and histological staging worsened after 2 years, as did the CPS II. However, QTLF, PIIINP, CPS I and the Mayo score revealed no significant changes.

CONCLUSIONS

Only CPS II changed after 2 years, whereas CPS I and the Mayo score remained unaltered. QTLF and PIIINP did not provide any further information on progression of PBC, suggesting that QTLF cannot predict prognosis of PBC patients in a two-year interval and that CPS II is superior to CPS I and the Mayo score in short-term studies for PBC.

Time-dependent Cox regression model is superior in prediction of prognosis in primary sclerosing cholangitis

More precise prognostic models are needed for prediction of survival in patients with primary sclerosing cholangitis (PSC), particularly for the selection of candidates for liver transplantation. The aim of this study was to develop a time-dependent prognostic model for the calculation of updated short-term survival probability in PSC. Consecutive clinical and laboratory follow-up data from the time of diagnosis were collected from the files of 330 PSC patients from 5 European centers, followed for a median of 8.4 years since diagnosis. Time-fixed and time-dependent Cox regression analyses, as well as the additive regression model, were applied. The reliability of the models was tested by a cross-validation procedure. Bilirubin (on a logarithmic scale), albumin, and age at diagnosis of PSC were identified as independent prognostic factors in multivariate analysis of both the time-fixed and the time-dependent Cox regression models. The importance of bilirubin was more pronounced in the time-dependent model (hazard ratio [HR], 2.84) than in the time-fixed analysis (hazard ratio, 1.51). The additive regression model indicated that once the patients survive beyond the first 5 years, the impact on prognosis of albumin at diagnosis ceases. The time-dependent prognostic model was superior to the time-fixed variant in assigning low 1-year survival probabilities to patients that actually survived less than 1 year. In conclusion, a time-dependent Cox regression model has the potential to estimate a more precise short-term prognosis in PSC compared with the traditional time-fixed models.

Autoimmune liver disease. Current standards, future directions

The diagnosis and management of autoimmune hepatitis continues to evolve as new diagnostic tests and new therapies are added to the armamentarium. Also encouraging are the advances in the understanding of the human immune system and its involvement in the origin and course of auto immune diseases in general and in the variants of autoimmune liver disease. Promising changes are expected in the next few years as new medications become available to the practicing hepatologist. New immune tests may allow therapies to be customized to patients, and antiviral therapies may also eventually be used in the management of this autoimmune liver diseases.

Primary biliary cirrhosis: survival of a cohort followed for 10 years

OBJECTIVES

To study the natural course of primary biliary cirrhosis (PBC) in order to be able to design accurate clinical pharmacological studies and evaluate the need for liver transplantation.

DESIGN

A cohort of 86 patients with PBC living in northern Sweden was followed for a 10-year period during 1983-93. No patients received therapy with ursodeoxy cholic acid or other drugs during the follow-up period.

METHOD

At start all patients were investigated personally by the authors. At follow-up medical notes were scrutinized and special questionnaires to the current responsible physician were applied. Endpoints were the time of dropout, liver transplantation, death or end of the study period.

RESULTS

At follow-up data were available for 84 patients (97%). During the study period 34 patients died, of whom 28 were symptomatic; 15 deaths had no direct connection to PBC. Nineteen deaths were related to PBC of whom two were asymptomatic, the most common cause being end-stage liver disease with liver coma. During the study period in all eight patients were subjected to liver transplantation.

CONCLUSIONS

The survival rate of the 32 asymptomatic PBC patients at the start of the study was the same as a sex- and age-matched standard background population. Those patients with symptomatic PBC from the beginning of study had a survival rate at 10 years of 50%, and the most ominous sign was a bilirubin greater than 35 micromol L(-1) . Liver transplantation was performed in almost 10% in this cohort until 1993. Since then, the indications and referral practice for liver transplantation has changed and is now higher.

The pyruvate dehydrogenase complex as a target autoantigen in primary biliary cirrhosis

Mitochondrial autoantigens and their B and T cell autoepitopes have been well defined in primary biliary cirrhosis (PBC). However, the relationships of the antimitochondrial antibodies and the mechanisms of bile duct destruction in PBC remain an enigma. The serological hallmark of PBC remains the presence of antibodies to mitochondria, particularly to the E2 component of the pyruvate dehydrogenase complex (PDC-E2). However, several mechanisms may now be proposed which may explain the immune-mediated bile duct damage in PBC. These include the possible role of T cell-mediated cytotoxicity as well as the interaction between the IgA class of antimitochondrial antibodies and the mitochondrial autoantigens. A prominent feature in this discussion is the highly directed and specific immune response to the mitochondrial antigens, including PDC-E2 as well as other members of the 2-oxo-acid dehydrogenase complexes. Ultimately, the mechanisms that lead to this immune reaction should provide data on other questions in PBC, including the reasons for female predominance, the absence of PBC in children and the relative ineffectiveness of immunosuppressive agents.

Adaptation of the Mayo primary biliary cirrhosis natural history model for application in liver transplant candidates

The Mayo natural history model has been used widely as a tool to estimate prognosis in patients with primary biliary cirrhosis (PBC), particularly liver transplant candidates. We present an abbreviated model in which a tabular method is used to approximate the risk score, which may be incorporated in the minimal listing criteria for liver transplant candidates. Data used in the development and validation of the original Mayo model were derived from 418 patients with well-characterized PBC. To construct an abbreviated risk score in a format similar to that of Child-Turcotte-Pugh score, 1 to 3 cut-off criteria were determined for each variable, namely age (0 point for <38, 1 for 38 to 62 and 2 for >/=63 years), bilirubin (0 point for <1, 1 for 1 to 1.7, 2 for 1.7 to 6.4, and 3 for >6.4 mg/dL), albumin (0 point for >4.1, 1 for 2.8 to 4.1, and 2 for <2.8 g/dL), prothrombin time (1 point for normal and 2 for prolonged) and edema (0 point for absent and 1 for present). The intervals between these criteria were chosen in a way to enable a meaningful classification of patients according to their risk for death. This score is highly correlated with the original risk score (r = 0.93; P <.01). The Kaplan-Meier estimate at 1 year was 90.6% in patients with a score of 6. The abbreviated risk score is a convenient method to quickly estimate the risk score in patients with PBC. An abbreviated score of 6 may be consistent with the current minimal listing criteria in liver transplant candidates.

Primary biliary cirrhosis: new perspectives in diagnosis and treatment

Primary biliary cirrhosis (PBC) is a chronic autoimmune disease characterised by cholestatic liver function tests, antimitochondrial antibodies, and abnormal liver histology. Early descriptions of a rare rapidly progressive disease no longer reflect the more indolent progress often seen today. Many patients have significant long term morbidity through symptoms such as fatigue and itch with a minority progressing to liver failure and need for transplantation. The current data on the diagnosis, clinical progression, and treatment of PBC are reviewed.

Is serum bilirubin concentration the only valid prognostic marker in primary biliary cirrhosis?

From the many prognostic models for primary biliary cirrhosis (PBC) patients based on Cox's regression analysis, the Mayo model has gained the most popularity and was successfully validated in some centers. The aim of our study was to validate the Mayo survival model for Polish PBC patients and, in case of its inapplicability, to select prognostic variables and to create time-fixed and time-dependent survival models for the patients. We used database information on patients from 6 medical centers in Poland, fulfilling clinical, serological, and/or pathological criteria of PBC. The Mayo model was validated using data from 116 PBC patients. The time-fixed and time-dependent models were created using data on clinical and biochemical variables used in the Mayo model from 162 and 208 patients, respectively. The Mayo model validation was performed graphically and by one-sample log-rank tests after dividing the study sample into 3 groups of high, medium, and low risk. The survival analysis was performed using Cox's proportional hazards regression method on clinical and biochemical variables used in the Mayo model. Treatment with ursodeoxycholic acid (UDCA) was included in the time-dependent analysis. Validation showed that the Mayo model overestimated death risk in Polish PBC patients. Of the variables used in the Mayo model, serum bilirubin concentration appeared to be the only variable of prognostic importance. The analysis shows that serum bilirubin concentration holds most of the prognostic information for our PBC patients irrespective of prior treatment with UDCA.

Primary biliary cirrhosis once rare, now common in the United Kingdom?

There is a widespread impression that the number of patients with the autoimmune liver disease primary biliary cirrhosis (PBC) is increasing, although its incidence and prevalence vary widely. Using thorough case-finding methods and rigorous definitions to assess changes in incidence and prevalence with time and to explore the symptomatology and mortality of the disease in a large group of unselected patients, we performed a descriptive epidemiological study of PBC in a well defined population over a fixed period of time using established diagnostic criteria and with clinical follow-up of all cases. In a population of 2.05 million in northern England 770 definite or probable PBC cases were identified. Prevalence rose from 201.9 per 10(6) in the adult population and 541. 4 per 10(6) women over 40 in 1987 to 334.6 per 10(6) adults and 939. 8 per 10(6) women over 40 in 1994. Incidence was 23 per 10(6) in 1987 and 32.2 per 10(6) in 1994. Three hundred patients died in median follow-up of 6.27 years (141 liver deaths); the standardized mortality ratio was 2.85. At presumed diagnosis, 60.9% had no symptoms of liver disease. By June 1994 62% of prevalent patients had liver symptoms. PBC is apparently increasing. It is still unclear whether this is because of a true increase, case finding, or increased disease awareness. The study draws attention to (1) high mortality from liver disease and non-liver-related causes even in patients initially with no liver symptoms and (2) apparently poor diagnostic awareness of the disease.

Utilization of the Mayo risk score in patients with primary biliary cirrhosis receiving ursodeoxycholic acid

BACKGROUND/AIMS

Ursodeoxycholic acid (UDCA) is an effective therapy for most patients with primary biliary cirrhosis (PBC). During the management of these treated patients, a number of clinically important issues arose including which patients might be candidates for combined therapy, which patients require endoscopy for variceal bleeding, and how survival can be predicted during treatment. Our aims were: 1) to identify factors associated with a suboptimal response to UDCA in patients with PBC; 2) to define a simple, non-invasive method to predict those PBC patients most apt to have esophageal varices; and 3) to determine the reliability of the Mayo survival model in predicting the course of UDCA treated patients.

METHODS

We analyzed the prospectively collected data of 180 patients, who we continue to follow, with PBC who participated in a randomized, placebo-controlled trial of UDCA.

RESULTS

After six months of UDCA therapy, patients with serum alkaline phosphatase levels less than twice normal (p < 0.04), and/or a Mayo risk score < 4.5 (p < 0.04) were more likely to respond favorably to treatment over a two year period. The Mayo risk score was the single risk factor independently predictive of development of varices (p < 0.01); 93% of patients who developed varices had a Mayo risk score > or = 4. The Mayo survival model, recalculated after 6 months on UDCA therapy accurately predicted patient survival.

CONCLUSIONS

Suboptimal responders to UDCA can be identified by assessment of serum alkaline phosphatase levels, and/or Mayo risk score. A Mayo risk score above 4 helps in selecting patients for endoscopic surveillance for varices and the Mayo survival model accurately predicts the clinical course in patients with PBC receiving UDCA.