Treatment response and clinical event-free survival in autoimmune hepatitis: A Canadian multicentre cohort study.

BACKGROUND & AIMS: Treatment outcomes for people living with autoimmune hepatitis (AIH) are limited by a lack of specific therapies, as well as limited well-validated prognostic tools and clinical trial endpoints. We sought to identify predictors of outcome for people living with AIH. METHODS: We evaluated the clinical course of people with AIH across 11 Canadian centres. Biochemical changes were analysed using linear mixed-effect and logistic regression. Clinical outcome was dynamically modelled using time-varying Cox proportional hazard modelling and landmark analysis. RESULTS: In 691 patients (median age 49 years, 75.4% female), with a median follow-up of 6 years (25th-75th percentile, 2.5-11), 118 clinical events occurred. Alanine aminotransferase (ALT) normalisation occurred in 63.8% of the cohort by 12 months. Older age at diagnosis (odd ratio [OR] 1.19, 95% CI 1.06-1.35) and female sex (OR 1.94, 95% CI 1.18-3.19) were associated with ALT normalisation at 6 months, whilst baseline cirrhosis status was associated with reduced chance of normalisation at 12 months (OR 0.52, 95% CI 0.33-0.82). Baseline total bilirubin, aminotransferases, and IgG values, as well as initial prednisone dose, did not predict average ALT reduction. At baseline, older age (hazard ratio [HR] 1.25, 95% CI 1.12-1.40), cirrhosis at diagnosis (HR 3.67, 95% CI 2.48-5.43), and elevated baseline total bilirubin (HR 1.36, 95% CI 1.17-1.58) increased the risk of clinical events. Prolonged elevations in ALT (HR 1.07, 95% CI 1.00-1.13) and aspartate aminotransferase (HR 1.13, 95% CI 1.06-1.21), but not IgG (HR 1.01, 95% CI 0.95-1.07), were associated with higher risk of clinical events. Higher ALT at 6 months was associated with worse clinical event-free survival. CONCLUSION: In people living with AIH, sustained elevated aminotransferase values, but not IgG, are associated with poorer long-term outcomes. Biochemical response and long-term survival are not associated with starting prednisone dose. IMPACT AND IMPLICATIONS: Using clinical data from multiple Canadian liver clinics treating autoimmune hepatitis (AIH), we evaluate treatment response and clinical outcomes. For the first time, we apply mixed-effect and time-varying survival statistical methods to rigorously examine treatment response and the impact of fluctuating liver biochemistry on clinical event-free survival. Key to the study impact, our data is 'real-world', represents a diverse population across Canada, and uses continuous measurements over follow-up. Our results challenge the role of IgG as a marker of treatment response and if normalisation of IgG should remain an important part of the definition of biochemical remission. Our analysis further highlights that baseline markers of disease severity may not prognosticate early treatment response. Additionally, the initial prednisone dose may be less relevant for achieving aminotransferase normalisation. This is important for patients and treating clinicians given the relevance and importance of side effects.

Ethnicity, disease severity, and survival in Canadian patients with primary biliary cholangitis.

BACKGROUND AND AIMS: We investigated associations between ethnicity, survival, and disease severity in a diverse Canadian cohort of patients with primary biliary cholangitis (PBC). APPROACH AND RESULTS: Patients with PBC were included from the Canadian Network for Autoimmune Liver Disease. Ethnicity was defined using a modified list adopted from Statistics Canada, and ethnicities with small samples were grouped. Clinical events were defined as liver decompensation, HCC, liver transplantation, or death. Clinical event-free and liver transplantation-free survival were analyzed using Cox regression. Trajectories of serum liver function tests were assessed over time using mixed-effects regression. Health-related quality of life was assessed using the Short Form 36, the PBC-40 questionnaire, and the 5-D Itch scale and analyzed using mixed-effects regression. The cohort included 1538 patients with PBC from six sites and was comprised of 82% White, 4.7% Indigenous, 5.5% East Asian, 2.6% South Asian, and 5.1% miscellaneous ethnicities. Indigenous patients were the only ethnic group with impaired liver transplant-free and event-free survival compared to White patients (HR, 3.66; 95% CI, 2.23-6.01; HR, 3.09; 95% CI, 1.94-4.92). Indigenous patients were more likely to have a clinical event before diagnosis (10%) than all other ethnic groups despite similar age at diagnosis. Indigenous patients presented with higher alkaline phosphatase, total bilirubin, and GLOBE scores than White patients; and these relative elevations persisted during follow-up. CONCLUSIONS: Indigenous Canadians with PBC present with advanced disease and have worse long-term outcomes compared to White patients.

Loss of biochemical response at any time worsens outcomes in UDCA-treated patients with primary biliary cholangitis.

Background & Aims: Biochemical response to ursodeoxycholic acid (UDCA) therapy is associated with good prognosis in people living with primary biliary cholangitis (PBC). Biochemical response is typically assessed early in disease and it is not known what proportion of patients lose previously attained biochemical response, nor whether this impacts long-term liver transplant (LT)-free survival. Methods: We identified all UDCA-treated patients with PBC from the Canadian Network for Autoimmune Liver disease with biochemical measurements at 1 year, and evaluated their liver biochemistry over time. Inadequate biochemical response was defined as serum alkaline phosphatase ≥1.67x the upper limit of normal or abnormal serum total bilirubin at 1 year of UDCA therapy and all time points thereafter. Multistate Markov models were used to estimate transition rates between biochemical response states and from each state to LT or death. Results were validated in an external cohort (GLOBAL PBC registry). Results: A total of 823 patients from eight centers were included. Mean age at diagnosis was 53 years, 91% were female, 33% had inadequate biochemical response to UDCA at 1 year (n = 269). Patients who retained initial adequate response had lower rates of LT or death compared to patients who subsequently lost response (relative rate 0.102, 95% CI 0.047-0.223). Patients who regained adequate response had lower rates than patients who did not (0.016, 95% CI 0.001-0.568), and patients who lost response once more (0.010, 95% CI 0.001-0.340). Patients who regained adequate response for a third time also had lower rates than patients who did not (0.151, 95% CI 0.040-0.566). Analyses in the GLOBAL PBC registry (n = 2,237) validated these results. Conclusion: Loss of biochemical response at any time is associated with heightened risks of LT or death in people living with PBC. Achievement of biochemical response is an important goal throughout follow-up, regardless of biochemical response profile early in therapy. Impact and implications: Early biochemical response to ursodeoxycholic acid is associated with good prognosis in patients with primary biliary cholangitis (PBC). Our work demonstrates that patients with PBC transition between biochemical response states over time, and that these transitions correspond with changes in risk of liver transplantation or death. Clinicians should re-evaluate risk and optimize treatment decisions for patients with PBC throughout follow-up, regardless of early biochemical response to therapy.

Clinical characterization of patients with primary biliary cholangitis: A report from multiple Canadian centres.

Background: Primary biliary cholangitis (PBC) is a rare, chronic autoimmune, cholestatic liver disease affecting approximately 318 per million Canadians. There is limited information regarding the characterization of this patient population in Canada. Consequently, we aim to describe a cohort of PBC patients managed across liver centres serving this type of population. Methods: A cross-sectional examination of 1,125 PBC patient charts at 15 liver centres across Canada was conducted between January 2016 and September 2017. Results: Data from 1,125 eligible patients were collected from 7 Canadian provinces. The patient population was largely female (90.2%), had a median overall age of 61.3 years, and a median overall time since diagnosis of 6.4 years. Of the patients included in the study, 89% were on ursodeoxycholic acid (UDCA) therapy at a median dose of 14.0 mg/kg/day and 4.4% were previously treated with UDCA, whereas 6.6% were never treated with UDCA. Of the patients with available data (n = 1067), 289 (27.1%) presented with alkaline phosphatase (ALP) levels ≥200 IU/L and/or total bilirubin levels ≥21 µmol/L. Assessment of UDCA treatment response revealed that 26.6% and 38.3% of patients were inadequate responders according to the Toronto and Paris-II criteria, respectively. Mortality occurred in 1.2% (14) of patients, with liver-related adverse outcomes being more commonly observed in patients who discontinued UDCA compared to those who are currently on treatment (36.3% and 19.6%, respectively). Conclusion: This study showed that Canadian PBC patients present with demographics and features commonly reported in the literature for this disease. Over one third of PBC patients had inadequate response to UDCA treatment or were not currently being treated with UDCA. Consequently, there is a significant unmet therapeutic need in this Canadian PBC population.