Homeostatic model assessment of insulin resistance closely related to lobular inflammation in nonalcoholic fatty liver disease.

Objective: Insulin resistance (IR) has been established as a major risk factor for nonalcoholic fatty liver disease (NAFLD) where it exerts effects on plasma glucose homeostasis, cellular anabolism, and organ glucose uptake. Owing to paucity of studies focused on peripheral IR in relation to pathological outcome, we aim to investigate homeostatic model assessment of insulin resistance (HOMA-IR) by histological characteristics of NAFLD.

Methods: Liver biopsy of 588 patients was screened. After excluding etiologies other than NAFLD and factors contributing to IR, serum HOMA-IR was compared with patients' histologic features. Univariate and multivariate analyses were conducted to assess their relationship. Area under the receiver operating characteristic (AUROC) was calculated to assess the discriminatory ability of homeostatic model assessment of IR for advanced lobular inflammation (LI).

Results: We observed higher serum level of alanine aminotransferase, aspartate aminotransferase, gamma-glutamyl transferase, and low-density lipoprotein as HOMA-IR increased. HOMA-IR is significantly associated with severity of LI (odds ratio = 1.222, 95% confidence interval = 1.135-1.315, P < 0.001), similar association remained after adjusting for age, BMI, hemoglobin A1c, alanine aminotransferase, aspartate aminotransferase, low-density lipoprotein, high-density lipoprotein, and triglycerides (odds ratio = 1.205, 95% confidence interval = 1.102-1.317, P < 0.001). HOMA-IR is discriminant of LI with AUROC = 0.832 and cutoff = 2.995 (sensitivity = 0.938, specificity = 0.569).

Conclusion: This study demonstrated a strong and independent association of HOMA-IR with the severity of liver inflammation by histological evaluation in NAFLD patients without diabetes or metabolic syndrome, and its possible role in diagnosis of LI could be translated into clinical assessment of NAFLD patients with uncertainty of nonalcoholic steatohepatitis progression.