Influence of insulin resistance in obese patients on elevated serum alanine aminotransferase.

BACKGROUND AND OBJECTIVE: Insulin resistance has been associated with fat liver and non-alcoholic fatty liver disease. The aim of our study was to study the influence of insulin resistance in obese patients on elevated serum alanine aminotransferase.

RESEARCH METHODS: A population of 91 obesity non diabetic outpatients was analyzed in a cross sectional study. HOMA-IR was calculated as indicator of insulin resistance.

RESULTS: The mean age was 39.2 +/- 16.7 years and the mean BMI 34.4 +/- 5.2. Patients were classified as group I (control, n=74) when serum (Alanine Aminotransferase) ALT activity was normal or group II (NAFLD, n=17) when serum ALT activity was greater than the upper limit of normal reference laboratory (> or =43 UI/L). Waist circumference, fat mass and hip to waist ratio were higher in group II. Insulin (13.5 +/- 7.8 mUI/L vs 24.9 +/- 16.7 mUI/L; p < 0.05), HOMA-IR (1.9 +/- 1.1 vs 3.9 +/- 2.8), and triglycerides levels (115.1 +/- 66.8 mg/dl vs. 153.2 +/- 71.2 mg/dl; p < 0.05) were higher in group II than group I. In the logistic regression analysis with a dependent dicotomic variable (ALT; group I and group II), the HOMA-IR remained in the model, with an Odd's Ratio to develop ALT >43 U/L of 2.18 (CI:95%: 1.12-4.2) with each 1 unit of HOMA-IR adjusted by age, sex, weight, and dietary intake.

CONCLUSION: Insulin resistance in obese patients is associated with ALT activity. Further study is needed to evaluate histological changes and new treatments in these patients.