Adiponectin predicts subclinical atherosclerosis in nonalcoholic fatty liver disease

By Lorraine L. Janeczko

NEW YORK (Reuters Health) - In patients with nonalcoholic fatty liver disease (NAFLD), adiponectin is a better predictor of subclinical atherosclerosis than are liver function tests, according to new research from Israel.

This suggests that adiponectin plays an active role in the pathophysiology of vascular disease in this group, the authors report online March 14 in Journal of the American Society of Hypertension.

In patients with NAFLD, serum adiponectin levels were significantly positively associated with indices of subclinical atherosclerosis, such as pulse wave velocity (PWV) and aortic augmentation index (AI), they write.

"This association was independent of age, sex, and blood pressure level," said senior author Dr. Marina Shargorodsky of Wolfson Medical Center in Holon and Sackler Faculty of Medicine of Tel Aviv University, in an email to Reuters Health.

"Advanced liver disease is associated with paradoxically increased adiponectin level, and adiponectin is associated with increased arterial stiffness, which is considered a surrogate for atherosclerotic disease as well as a predictor of cardiovascular mortality," she said.

Asked whether serum adiponectin levels should be routinely measured in patients with NAFLD, Dr. Shargorodsky replied, "These findings may have implications for the long-term cardiovascular health of NAFLD patients. The association between adiponectin and impaired vascular stiffness, even before the development of cardiovascular disease, obligates more aggressive and earlier concomitant cardiovascular risk factor management in this patient population."

"Moreover, follow up of circulating adiponectin level can predict progression of the liver disease. Increased adiponectin after initial decreased adiponectin levels could predict hepatic fat decline with advanced fibrosis as well as increased cardiovascular morbidity and mortality risk," she said.

Dr. Shargorodsky and her colleagues studied 52 patients with NAFLD who were outpatients at one medical center and had a mean age of 53.5 years.

The patients were screened by physical exam, complete blood chemistry, complete blood count, urinalysis, and electrocardiography.

Patients with a history of unstable angina, myocardial infarction, cerebrovascular accident, or major surgery within the past six months were excluded.

Subjects remained on all of their medications for up to three months to prevent possible effects on the study variables, and were instructed to consult the study physician if any change in medical treatment was suggested by another physician.

PWV and AI were assessed using the SphygmoCor system.

The researchers found that adiponectin was significantly, positively associated with PWV (r=0.348; p=0.011) and with AI (r=0.467; p<0.0001).

They also found significant positive associations between circulating adiponectin and aortic systolic pressure (r=0.295; p=0.034) and aortic pulse pressure (r=0.309; p=0.026).

There was no association between arterial stiffness parameters and liver function tests.

Dr. Sammy Saab of Ronald Reagan UCLA Medical Center and David Geffen School of Medicine at UCLA in Los Angeles, California, said in an email, "Fatty liver disease tends to occur in the context of the metabolic syndrome with diabetes, obesity, hypertension, and hypercholesterolemia. Many patients with fatty liver are at increased risk for heart disease. Serum adiponectin levels may identify those at highest risk so we can intervene."

Dr. Saab, who was not involved in the study, advised against routinely measuring serum adiponectin levels in patients with NAFLD, saying, "More data are needed for us to know how to interpret the results."

"This is an important study," Dr. Saab said, "but the results are very preliminary. Additional research is necessary to confirm the results. Serum adiponectin levels may not completely be associated with severity of fatty liver."

"This study highlights the need for additional studies in patients with fatty liver. Fatty liver is a huge public and medical concern across the world. Treatment generally involves treating the underlying process, which is the metabolic syndrome," he said.

The authors advised that the precise mechanisms for these vascular effects and the clinical impact of increased adiponectin levels on cardiovascular outcomes in patients with advanced NAFLD deserve further investigation.

SOURCE: http://bit.ly/1mYX29l

J Am Soc Hypertens 2014.