NAFLD Is a Risk Factor for Diabetes, Metabolic Syndrome

November 15, 2007 (Boston) — Patients with nonalcoholic fatty liver disease (NAFLD) and elevated alanine aminotransferase (ALT) levels have a high risk of developing diabetes and metabolic syndrome, possibly because of other associated risk factors, including obesity, insulin resistance, and hyperglycemia, according to a poster presented here at the American Association for the Study of Liver Diseases (AASLD) 58th Annual Meeting.
Leon Adams, MD, from the University of Western Australia in Nedlands, presented the data from an 11-year follow-up study of patients. He and his team found that people with NAFLD were 3 times more likely to develop diabetes than those without NAFLD.
"If you are diagnosed with NAFLD, there should clearly be an emphasis on modifying the risk factors — principally excess weight — because you will be at risk for developing diabetes," Dr. Adams said.
The study looked at the 358 residents of Busselton, Western Australia, who were assessed in 1994 and 1995 as part of the Busselton Health Survey. After ruling out liver damage from alcohol, drug toxicity and viral, metabolic, and autoimmune liver disease, NAFLD was diagnosed on the basis of an elevated serum ALT level (>40 U/L). All of the patients — both those with NAFLD and those without the condition — were reexamined in 2005 for liver complications, diabetes (fasting glucose > 7.0 mmol/L or history), and metabolic syndrome.
After excluding patients with existing diabetes, those with NAFLD were more likely to develop diabetes on follow-up (20 [18.9%] of 106 vs 15 [6.1%] of 246; P < .001). Furthermore, NAFLD patients were more likely to develop metabolic syndrome at follow-up (27 [33.3%] of 81 vs 51 [22.6%] of 226; P = .056).
Some of the risk may be driven by other metabolic risk factors such as obesity, insulin resistance, and hyperglycemia, according to the study. Still, there is an association between NAFLD and both diabetes and metabolic syndrome, and not all patients — or physicians — know about it, Dr. Adams said.
"We're trying to get the message out there that you need to be aware that [these patients] are not only at risk of liver disease but [are] also at risk for developing diabetes [and] metabolic syndrome," he noted.
Although this is a small study that confirms earlier findings, it is important for that reason alone, said Arun Sanyal, MD, a member of the AASLD governing board and a researcher at Virginia Commonwealth University in Richmond.
"It is an important point," he added. "The word has not percolated out that having a little fat in the liver is a risk factor [for diabetes and metabolic syndrome]."
In another NAFLD poster, researchers from the University of Michigan tried to validate a "fibrosis score" that was developed last year to determine the presence of advanced fibrosis in patients with NAFLD. The original study, published in the April 2007 issue of Hepatology, concluded that a liver biopsy could be avoided in 75% of patients with 90% accuracy with the liver fibrosis score.
In the current study, however, the University of Michigan researchers correctly predicted the absence or presence of fibrosis in 93% (negative predictive value) and 42% (positive predictive value) cases, respectively. Overall, a liver biopsy could be avoided in 48 patients (61%) using their cutoff scores.
Dr. Adams has disclosed no relevant financial relationships.
American Association for the Study of Liver Diseases 58th Annual Meeting: Abstracts 1139 and 1153. Presented November 5, 2007.