PBC Disease Models

These simple conceptual models help explain different aspects of Primary Biliary Cholangitis, including disease activity, symptom burden, treatment pathways, and the real-world experience of living with PBC.

PBC Good Care Guide

The PBC Good Care Guide explains what good medical care for Primary Biliary Cholangitis should look like for most patients, from diagnosis through long-term monitoring. It helps patients understand the typical steps in PBC care, including treatment, monitoring, and symptom management. By understanding this pathway, patients can have more informed conversations with their healthcare team and feel more confident they are receiving appropriate care. Click here or on image below for more information.

PBC Activity Dial (PBC-AD)

The PBC Activity Dial (PBC-AD) is a simple visual guide developed by PBC Ireland to help explain how active Primary Biliary Cholangitis (PBC) may be at any given time. Instead of describing PBC as a fixed set of stages, the dial shows disease activity as a continuum ranging from well-controlled disease (green) to advanced liver disease (red). The position on the dial reflects factors such as liver blood tests, response to treatment, and overall risk of progression. Importantly, people with PBC can move between zones depending on how well treatment is working and how the disease responds over time. The goal of treatment is to keep the disease in the green zone, where liver tests are normal or near normal and the risk of progression is lowest.

PBC Symptom-Activity Discordance Model (PBC-SADM)

The PBC Symptom-Activity Discordance Model illustrates an important feature of Primary Biliary Cholangitis: how a patient feels and how active the disease appears biologically do not always match. In some people, liver blood tests may look relatively stable while symptoms such as fatigue, itch, or cognitive difficulties significantly affect daily life. In others, patients may feel well even though blood tests suggest ongoing disease activity. The model therefore maps PBC across two dimensions: patient-reported symptom burden and biological disease activity, creating four possible states: Stable and Coping, Invisible Suffering, Silent Risk, and High-Impact Disease. By highlighting these different patterns, the model helps patients and clinicians recognise that both biological markers and patient experience are important when assessing PBC and planning ongoing care.

PBC Treatment Response Model (PBC-TRM)

The PBC Treatment Response Model illustrates how treatment for Primary Biliary Cholangitis is started, monitored, and formally assessed to determine whether the disease is under good control. After diagnosis, patients usually begin treatment with ursodeoxycholic acid (UDCA/Urso) and are monitored during the first year with blood tests and clinical assessment. At around 12 months, doctors evaluate the biochemical response, particularly alkaline phosphatase (ALP) and bilirubin levels. A good response is associated with a lower long-term risk of liver disease progression, while an incomplete response may prompt reassessment of treatment and consideration of additional therapies. The model highlights that effective PBC care involves ongoing evaluation and adjustment of treatment over time.

PBC Long-Term Management Model (PBC-LTMM)

The PBC Long-Term Management Model illustrates the key elements of ongoing care for people living with Primary Biliary Cholangitis (PBC). Beyond initial treatment, long-term care requires regular monitoring of liver disease, management of symptoms such as fatigue and pruritus, optimisation of medications, and surveillance for complications. It also includes attention to extrahepatic conditions, lifestyle support, and patient education. Together, these components form a continuous cycle of care, where patients are regularly reassessed and treatment strategies are adjusted to support both clinical outcomes and quality of life.

PBC Iceberg Model (PBC-IM)

The PBC Iceberg Model (Clinically Visible Disease and Hidden Burden) illustrates how the aspects of Primary Biliary Cholangitis that are most visible in clinical care represent only part of the disease experience. During clinic visits, discussions often focus on clinical indicators such as blood tests, fibrosis stage, imaging results, and medications. However, beneath the surface many patients experience symptoms such as fatigue, itching, and cognitive difficulties, along with broader impacts on daily life, work, and emotional wellbeing. These deeper layers of disease burden may be discussed less frequently in clinical consultations, yet they form a significant part of living with PBC. The model highlights the importance of recognising both the clinical and lived dimensions of the disease.

PBC Total Burden Equation (PBC-TBE / B=C+H)

The PBC Total Burden Equation is a conceptual model that illustrates how the total impact of Primary Biliary Cholangitis (PBC) arises from both clinically measurable disease and the lived experience of patients. In this model, the overall disease burden (B_PBC) is expressed as the sum of clinically visible disease (C), such as liver enzyme levels, bilirubin, imaging findings, and fibrosis stage, and the hidden patient burden (H), which includes symptoms like fatigue, pruritus (itch), cognitive difficulties, sleep disruption, and reduced quality of life. While clinical tests are essential for diagnosis and monitoring disease progression, they do not fully capture the day-to-day challenges faced by people living with PBC. The equation highlights the principle that understanding the true burden of the disease requires considering both measurable clinical indicators and patient-reported experiences together.

PBC Treatment Divergence Model (PBC-TDM)

The PBC Treatment Divergence Model illustrates how patients may diverge from the standard treatment pathway due to the interaction of biological, symptom, and practical factors. While PBC management often begins with a typical approach (diagnosis, initiation of ursodeoxycholic acid (UDCA), and monitoring of biochemical response), many patients experience challenges that alter this course. Biological factors such as delayed diagnosis, UDCA intolerance, incomplete biochemical response, or advanced disease may limit treatment options. At the same time, symptom factors including severe fatigue or refractory pruritus can significantly affect quality of life and influence treatment priorities. Practical considerations, such as medication tolerability, adverse effects, and adherence challenges, can also shape real-world management decisions. Together, these interacting influences help explain why patients may not follow a single, predictable treatment pathway.

PBC Treatment Balance Model (PBC-TBM)

The PBC Treatment Balance Model illustrates how optimal care in Primary Biliary Cholangitis requires balancing three domains: biological disease control, symptom burden, and practical treatment considerations. These three factors form the axes of the model. The centre represents the optimal balance between these domains, where treatment achieves the best overall outcome. In practice, care may be influenced by external drivers that shift the balance toward one domain. For example, clinician training, clinical guidelines, and laboratory markers often emphasise biological disease control, whereas patients may prioritise symptom relief or practical considerations such as medication tolerability, cost, or treatment burden.