Hypoadiponectinemia and its association with liver fibrosis in morbidly obese patients

Reduced serum levels of adiponectin have been associated with insulin resistance and non-alcoholic fatty liver disease (NAFLD). However, the relationship between serum adiponectin levels and hepatic histology in NAFLD is controversial. The aim of this study was to explore associations between plasma adiponectin concentrations and liver histology in morbidly obese patients.

We conducted a case-control study including obese patients undergoing bariatric surgery and normal controls. Anthropometric, standard biochemical variables as well as plasma adiponectin and leptin levels were determined. Liver biopsy was performed in all patients at the time of surgery.

Seventy morbidly obese patients (mean BMI, 40.6 ± 5.6 kg/m(2)) met the inclusion criteria and were compared with 69 controls (mean BMI, 22.8 ± 1.6 kg/m(2), p = 0.0001). Thirty patients (43%) had NAFLD and 20 (28%) of them fulfilled the histological criteria for steatohepatitis. Obesity was associated with increased leptin and decreased adiponectin levels. NAFLD patients exhibited decreased levels of serum adiponectin compared with matched controls [median (Q1-Q3), 3.9 (3.2-4.3) vs. 8.6 (6.5-9.2) μg/mL, p < 0.0001]. In univariate analysis, age, gender, type 2 diabetes mellitus, BMI, HOMA-IR, aspartate aminotransferase (AST), alanine aminotransferase, serum glucose, and adiponectin levels were independently associated with hepatic fibrosis. In multivariate analysis, AST [OR = 1.082 (1.000-1.170)], age [OR = 1.119 (1.023-1.225)], and serum adiponectin levels [OR = 0.529 (0.299-0.936)] were significantly associated with the presence of liver fibrosis.

NAFLD patients have lower plasma adiponectin concentrations than control subjects. Low adiponectin levels are associated with more severe liver histology. Serum adiponectin may be useful to estimate the severity of liver damage in obese patients with NAFLD.