Acanthosis nigricans in patients with nonalcoholic steatohepatitis: an uncommon finding

To determine the prevalence and the metabolic characteristics of acanthosis nigricans (AN) in a group of 28 study subjects with biopsy-proven nonalcoholic steatohepatitis (NASH).

The study participants (15 female and 13 male patients, 20 of whom were white subjects; mean body mass index, 32.7 +/- 5.7 kg/m2; mean age, 45.7 +/- 11.3 years) underwent an oral glucose tolerance test (OGTT), frequently sampled intravenous glucose tolerance test (FSIGT), and fasting metabolic panels. AN status was clinically determined, and fat mass was measured by dual-energy x-ray absorptiometry.

All study subjects had insulin resistance (IR), and 15 (54%) had the metabolic syndrome (by Adult Treatment Panel III criteria). Of the 28 patients, 4 (14%) had AN (AN+) and 24 did not (AN-). AN+ subjects had a higher body mass index (37.7 +/- 5.6 versus 31.5 +/- 4.3 kg/m2), fat mass (38.9 +/- 4.0 versus 29.2 +/- 2.3 kg), and leptin levels (17.2 +/- 3.9 versus 9.3 +/- 1.6 ng/mL) (P<0.05). They also had significantly higher indices of insulin secretion: fasting and stimulated insulin and C-peptide levels from OGTT and FSIGT. Metabolic syndrome prevalence was 40% in AN- versus 75% in AN+ subjects (not significantly different). Although the AN+ group had significantly lower fasting and OGTT-derived indices of insulin sensitivity in comparison with the AN- group, their FSIGT indices were similar. Waist circumference (a surrogate of visceral adiposity) and cytokine profiles were similar in the AN+ and AN- groups.

AN was not highly prevalent in our study cohort with NASH, despite the high prevalence of IR. Hyperinsulinemia and total adiposity, rather than visceral adiposity and IR, were the indices most predictive of AN. The use of AN as an index of IR in patients with NASH appears to have limited diagnostic value.