A new study from Indiana University suggests that people newly diagnosed with primary biliary cholangitis (PBC) who also have type 2 diabetes are more likely to develop fatty buildup in the liver, but they are not more likely to have worse liver scarring or shorter survival than those without diabetes.
The research, published in Digestive Diseases and Sciences, tracked more than 500 adults with PBC to better understand how common type 2 diabetes is in this group and whether it influences disease progression. The authors aimed to determine if diabetes, which is closely linked to fatty liver disease in the general population, also worsens liver damage in PBC.
To explore these connections, researchers examined the medical records of 562 adults with PBC who visited a single liver clinic between 2008 and 2022. About 15% of these patients had type 2 diabetes at their initial visit. A smaller group also underwent a special liver scan called transient elastography, which estimates liver fat and scarring without requiring a biopsy.
Among patients who underwent this scan, those with both PBC and diabetes were much more likely to have fatty liver. About 54% of people with both conditions met the criteria for a fatty liver, compared to only 28% of those with PBC alone. As for liver scarring, the two groups appeared similar. Rates of clinically significant scarring were not different between people with and without diabetes.
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The study also examined long-term outcomes. Over several years of follow-up, death rates and liver transplant rates were nearly identical in people with PBC regardless of whether they had diabetes. Fatty liver alone also did not affect the likelihood of death or needing a transplant.
Although diabetes did not increase the overall number of deaths during the study period, it did affect when those deaths occurred. One notable finding was that people with both PBC and diabetes tended to die at a younger age than those without diabetes, even though overall death rates were similar. The researchers suspect this may be due to heart and blood vessel disease, which was more common in the diabetes group, rather than liver disease itself.
The authors believe this may be because PBC and fatty liver disease tend to affect different parts of the liver in their early stages. That means having both conditions at the same time may not automatically make scarring worse, at least early on.
“Our study suggests that type 2 diabetes is associated with hepatic steatosis and a younger age of overall mortality in patients with PBC compared to those without type 2 diabetes,” the authors wrote.
The study had some notable limitations. Not everyone had the special liver scan, and liver biopsies were not routinely done, so very early liver changes could have been missed. The average follow-up time was also just over three years, which may not capture very long-term effects.
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