Fatty liver found in majority of type 2 diabetes patients

Six out of ten people with type 2 diabetes had fatty liver in a new study from Linköping University. Of these, only a small percentage had developed more severe liver disease. The study, published in the Journal of Internal Medicine, also helps confirm that those who have type 2 diabetes in combination with obesity are at greater risk of fatty liver leading to more severe liver disease.

When metabolism does not work normally, as with so-called metabolic syndrome, many organs in the body are affected.

Metabolic syndrome is a combination of factors leading to the body accumulating fat and not managing blood sugar levels in a good way. This entails an increased risk of developing secondary diseases, such as type 2 diabetes and cardiovascular diseases."

Wile Balkhed, PhD student at Linköping University and resident physician at Linköping University Hospital

For the liver, this can mean an increasing accumulation of fat, a condition called metabolic dysfunction-associated fatty liver disease (formerly called non-alcoholic fatty liver disease). Around one in five adults in Sweden is estimated to have metabolic dysfunction-associated fatty liver disease (MASLD). As many as one in three adults worldwide may be affected.

Fatty liver can lead to severe liver disease, such as cirrhosis, which is characterised by the formation of scar tissue in the liver. It is relatively rare, but for those who develop severe liver disease, it is linked to a high risk of liver cancer and high mortality.

"It's of great importance to find the few individuals who are at high risk of serious liver disease, because we can do a lot of good for those patients. But it's like looking for a needle in a haystack. Hopefully, our data will help to find the high-risk individuals among all patients," says Mattias Ekstedt, senior associate professor at Linköping University and consultant in gastroenterology and hepatology at Linköping University Hospital.

It is known that people with type 2 diabetes are at an increased risk of developing fatty liver. However, it is unclear how common this is because previous studies have given very different results. To obtain as representative data as possible, the researchers therefore wanted to investigate the presence of MASLD and cirrhosis of the liver in people with type 2 diabetes who attend diabetes checks in primary health care.

Of the more than 300 people with type 2 diabetes who participated in the study, close to six in ten (59 per cent) had metabolic dysfunction-associated fatty liver disease, according to MRI scans.

The researchers also used an ultrasound method that measures liver stiffness. These measurements showed that about 7 per cent of the participants had changes suggesting early-stage cirrhosis of the liver. This is a lower incidence than reported in previous studies, which have been done on patients in specialist clinics who more often have more severe disease.

"The finding is important for determining whether patients with type 2 diabetes should be screened for liver disease. Several international organisations recommend it in their guidelines, but such screening has not been introduced in Sweden," says Wile Balkhed.

The study also shows that obesity was a risk factor for liver disease advancing to cirrhosis. This is in line with what previous studies have found.

"People with both type 2 diabetes and obesity are a group at particular risk that healthcare should prioritise in future efforts. In our study, 13 per cent of this group had early-stage scarring of the liver, which was a much larger proportion than the two per cent in the group with type 2 diabetes without obesity," says Wile Balkhed.

Fortunately, fatty liver does not have to be a permanent condition. Fat in the liver can decrease significantly if the person loses weight.

The study provides a snapshot of what the study participants' livers looked like at a given point in time. In order to better understand how healthcare can find the individuals most at risk of severe liver disease, the researchers are now following up the patients in the study five years after the first examination.

The study has been carried out together with several healthcare centres in Östergötland in collaboration with the Center for Medical Image Science and Visualization (CMIV), at Linköping University and AMRA Medical AB. Researchers from several specialities, including hepatology, primary care, radiology, MR physics, clinical physiology and endocrinology, have collaborated in the study. Funding for the study was provided by, among others, Region Östergötland, the Knut and Alice Wallenberg Foundation, and the Swedish Society of Medicine.