Millions of people are living with two serious liver conditions at the same time, but doctors often miss the overlap because there's no agreed-upon way to diagnose it. Chronic hepatitis B (CHB) infection and metabolic dysfunction-associated steatotic liver disease (MASLD) are both major contributors to liver disease globally, yet the medical field lacks standardized diagnostic approaches for patients who have both conditions simultaneously.

The problem is urgent. Chronic hepatitis B alone causes an estimated 1.1 million deaths per year, despite the availability of a vaccine and antiviral treatments. For people living with hepatitis B, the lifetime risk of developing cirrhosis is approximately 40%, and the risk of primary liver cancer is roughly 20%, though these risks vary significantly depending on individual factors.

Meanwhile, metabolic dysfunction-associated steatotic liver disease is becoming increasingly common. Over one billion people worldwide now live with overweight or obesity, and more than 800 million have diabetes, both major risk factors for MASLD. An estimated 3% of people with MASLD will develop serious liver complications over 20 years.

What Happens When Hepatitis B and Metabolic Liver Disease Overlap?

The real challenge emerges in regions where both conditions are prevalent. In Africa, the Eastern Mediterranean, and the Western Pacific, hepatitis B is endemic, and metabolic disease rates are climbing rapidly. This creates a "critical nexus" where patients increasingly face both conditions simultaneously, fundamentally changing how liver disease will affect populations worldwide.

The problem isn't just medical; it's also about language and consistency. Until 2023, fatty liver disease was called "non-alcoholic fatty liver disease" (NAFLD), a term many found stigmatizing. The field then shifted to "metabolic dysfunction-associated fatty liver disease" (MAFLD), and now uses "metabolic dysfunction-associated steatotic liver disease" (MASLD). When inflammation or scarring is present, it's called "metabolic dysfunction-associated steatohepatitis" (MASH).

While these terminology changes improve consistency and reduce stigma, they've also created confusion. Different regions use different diagnostic tools, and the evidence supporting current diagnostic thresholds comes primarily from wealthy, developed countries. Data from Africa and the Eastern Mediterranean regions, where both hepatitis B and metabolic disease are significant public health threats, remain scarce.

Why Are Diagnostic Standards So Inconsistent?

Diagnosing MASLD requires identifying fatty liver disease plus at least one cardiometabolic factor. These factors include hypertension, type 2 diabetes, abnormal cholesterol levels, or obesity. However, the specific thresholds for these factors vary by population and geography, leading to inconsistent diagnoses.

Several factors complicate diagnosis across different populations:

• Genetic Variation: Different populations have different genetic predispositions to liver disease, affecting how the condition develops and progresses.
• Environmental and Dietary Factors: Local food systems, physical activity levels, and lifestyle patterns influence metabolic health and liver disease risk differently across regions.
• Resource Limitations: Wealthier countries have access to advanced imaging and blood tests, while resource-constrained settings rely on simpler tools that may be less accurate.
• Socioeconomic Factors: Income, education, and access to healthcare shape who gets diagnosed and when, creating health inequities.
• Migration Effects: When people move to new countries, their disease risk can change due to shifts in diet, activity, and healthcare access.

These overlapping complexities mean that current diagnostic algorithms can produce inconsistent results, especially in populations underrepresented in the research that established the thresholds.

How Can Doctors Better Diagnose and Monitor These Overlapping Conditions?

Experts are calling for a unified approach to diagnosis, monitoring, and risk assessment. The goal is to create standardized methods that work across diverse settings and populations, ensuring that patients receive consistent, evidence-based care regardless of where they live.

Key steps toward better diagnosis include:

• Consensus on Diagnostic Tools: The medical field needs to agree on which tests and thresholds to use for identifying MASLD in people with chronic hepatitis B, reducing confusion and inconsistency.
• Evidence-Based Monitoring Protocols: Establishing clear guidelines for how often patients should be tested and which biomarkers matter most helps catch disease progression early.
• Improved Risk Stratification: Doctors need better ways to identify which patients are at highest risk for serious complications, so resources can be directed where they're needed most.
• Enhanced Access to Interventions: Even with a diagnosis, many patients in low-resource settings lack access to treatments, vaccines, or antiviral medications that could prevent progression.
• Reduced Health Inequity: Diagnostic standards must be validated in diverse populations, not just wealthy countries, to ensure fairness and accuracy globally.

The stakes are high. MASLD is associated with a 1.5-fold increased risk of heart attack or stroke, a threefold higher risk of chronic kidney disease, and increased risk of cancers outside the liver. When combined with hepatitis B, these risks compound.

Unifying classification systems and improving diagnostic understanding across diverse populations is essential to advancing treatment pathways, tackling health inequities, and identifying specific actions that can save lives. Without standardized approaches, millions of people with overlapping liver diseases will continue to fall through the cracks, undiagnosed and untreated.