Rising burden of metabolic dysfunction-associated steatotic liver disease in China and clinical risk stratification among patients with type 2 diabetes

In many parts of the world, the liver is under a quiet, growing strain. For decades, doctors have known that when the body struggles to manage sugar and fat, the liver often pays the price by accumulating excess fat. This condition, once called non-alcoholic fatty liver disease, has recently been renamed metabolic dysfunction-associated steatotic liver disease to better reflect its deep connection to the body's overall metabolism. It is not a problem of the liver alone; it is a sign that the entire system for handling energy is out of balance. This issue is becoming increasingly common as populations age, diets change, and physical activity declines. The concern is that this silent accumulation of fat can eventually lead to serious scarring, liver failure, or cancer, placing a heavy burden on healthcare systems and families alike. Understanding how widespread this problem is, and how to spot it early in people who are already at risk, has become a critical priority for public health.

A new study from China brings together two very different ways of looking at this problem to paint a clearer picture of the challenge. The researchers combined a massive, national-level view of disease trends with a close-up look at individual patients in a hospital setting. On the broad scale, they analyzed data spanning thirty years, from 1990 to 2021, to track how many people in China were developing this liver condition, how many were living with it, and how many were dying from it. On the smaller scale, they examined the medical records of over a thousand adults who already had type 2 diabetes, a group known to be at high risk for liver problems. By weaving these two perspectives together, the team aimed to understand not just how big the problem is for the nation, but also how doctors can practically identify the condition in the people who need help the most.

The national data reveals a story of two opposing trends. The number of people in China developing and living with this liver condition has risen sharply over the last three decades. In 1990, the rate of new cases was roughly 496 per 100,000 people; by 2021, that number had climbed to about 622 per 100,000. Similarly, the total number of people living with the condition grew from approximately 137 million to nearly 291 million. This surge is driven largely by the country's growing population and the aging of its citizens, alongside a shift in how people live and eat. However, despite this massive increase in the number of people affected, the story of death and disability tells a different tale. The rate of death from this liver condition actually fell during the same period, dropping from about 1.04 deaths per 100,000 people to 0.82. The rate of years lost to disability also declined. This suggests that while more people are living with the disease, the healthcare system has become better at managing it so that it does not immediately lead to fatal outcomes. The burden is expanding in size, but the severity of the outcome for the average person has softened.

When the researchers looked at the most severe complications, the patterns became even more nuanced. The number of deaths and years of life lost due to liver scarring, known as cirrhosis, increased in total numbers because so many more people have the disease, but the rate of death per person actually went down. For liver cancer linked to this condition, the number of new cases and total deaths rose, yet the rate of death per person remained relatively steady. The study also identified the main drivers behind these changes. The growth of the population was the biggest factor increasing the total number of cases. However, for liver cancer specifically, changes in the disease itself—likely due to better control of other liver diseases like hepatitis—played a larger role. High levels of blood sugar and smoking were confirmed as major contributors to the burden of death and disability, highlighting that managing these specific risks is essential.

To understand how to catch this disease early, the team turned to a group of 1,073 adults with type 2 diabetes. In this group, more than half were found to have the liver condition. The researchers wanted to find simple, everyday tools that doctors could use to identify these patients without needing expensive or complex scans immediately. They tested several common measurements, including body mass index, waist size, and specific calculations based on blood sugar and fat levels. One calculation, known as the fatty liver index, which combines weight, waist size, blood fat, and a liver enzyme, proved to be the most effective tool. It was able to distinguish between those with and without the liver condition better than any other single measure. The study found that a specific score on this index served as a reliable threshold for identifying patients who likely have the condition and need further attention.

The analysis of these individual patients also revealed what the condition looks like in people with diabetes. Those with the liver condition tended to have higher blood pressure, higher blood sugar, and higher levels of triglycerides, a type of fat in the blood. They also had higher levels of certain liver enzymes, indicating mild stress on the liver. Interestingly, while their average blood sugar over time was similar to those without the condition, their fasting blood sugar and triglyceride levels were significantly higher. This suggests that the liver's struggle with fat and sugar happens even when the overall diabetes control appears similar. The study also noted that patients with the liver condition were less likely to be taking insulin, which may reflect that their diabetes was managed differently or that their specific metabolic profile differed.

Looking ahead, the researchers used statistical models to project what will happen over the next two decades. The outlook suggests that the number of people with this liver condition and the related scarring will continue to rise through 2045. The total number of people affected will grow as the population ages and expands. However, the rate of death and disability is expected to continue its slow decline, mirroring the trend seen in the past thirty years. For liver cancer, the projections are more optimistic, with rates of new cases and deaths expected to decrease. This future trajectory underscores a critical reality: the challenge is no longer just about preventing the disease from starting, but about managing a growing population of people who already have it.

The study concludes that while the national burden of this liver condition is expanding, the tools to manage it are becoming clearer. The combination of national data and clinical observation shows that while the disease is becoming more common, it is not necessarily becoming more deadly for the average person. For doctors working with patients who have type 2 diabetes, simple calculations based on routine blood tests and body measurements can serve as an effective early warning system. By using these straightforward indicators, healthcare providers can identify high-risk individuals sooner, allowing for earlier intervention. This approach links the big picture of national health trends with the practical reality of the clinic, offering a path forward for a condition that affects millions.