Non-alcoholic fatty liver disease: non-invasive markers and their importance in diagnosis

Objective — to evaluate the validity of serological markers in the diagnosis of non‑alcoholic fatty liver disease (NAFLD).Materials and methods. The investigation involved 122 patients with NAFLD aged 19 to 74, including 57 women (46.7 %) and 65 men (53.3 %). The following investigative methods have been used: anthropometric measurements (height, weight, waist circumference, BMI); ultrasound examination of the liver; laboratory (determination of lipid spectrum, insulin resistance, ALT, AST, fibrinogen, free oxyproline, oxyproline protein‑bound, hyaluronic acid, haptoglobin, apolipoprotein A1, a2‑macroglobulin, fibronectin); morphological (puncture biopsy of the liver with histological examination of biopsies); statistical (descriptive statistics, correlation, linear regression and ROC‑analysis).Results. The direct correlation between the degree of steatosis and level of protein‑bound oxyproline (r = 0.22; p < 0.05), the ratio of oxyproline protein‑bound/oxyproline free (r = 0.27; p < 0.05), the level of triglycerides (r = 0.33; p < 0.05), the level of VLDL (r = 0.29; p < 0.05). The direct correlation of moderate strength has been established between the degree of the activity of inflammatory process and levels of hyaluronic acid, a2‑macroglobulin and fibronectin (r = 0.54, 0.67 and 0.55, respectively; p < 0.05 for all) and a moderate inverse relationship for apo‑lipoprotein A1 (r = – 0.56; p < 0.05), haptoglobin (r = – 0.33; p < 0.05) and albumin (r = – 0.45; p < 0.05). Evaluation of correlations showed a direct relationship between the stage of fibrosis and the level of hyaluronic acid, a2‑macro­globulin and fibronectin (r = 0.72, 0.93 and 0.71 at p < 0.05) and a weak relationship with total bilirubin (r = 0.26; p < 0.05). Moderate feedback (r = – 0.61 and ‑0.35 — 0.32; p < 0.05, respectively) was found between apolipoprotein A1, haptoglobin, albumin and fibrosis stage.Conclusions. In patients with steatohepatitis, high diagnostic value was determined for non‑invasive markers of fibrosis: a2‑macroglobulin, apolipoprotein A1, hyaluronic acid and fibronectin for which the area under the ROC curve for minimal fibrosis was not less than 0.75, but more than moderate 0.9. Patients with liver cirrhosis showed a high level of sensitivity (96.4 — 100.0 %) and specificity (75.0 — 100.0 %) of these markers.