*3.5. Association of Circulating miRNAs With Clinical Variables*

We next examined the association between miRNA expression levels and clinical-pathological variables of the patient cohort. The levels of miRNA-451a (r = −0.2118), miRNA-142-5p (r = −0.2074), Let-7f-5p (r = 0.3426), miRNA-122-5p (r = 0.2193), and miRNA-29a-3p (r = 0.2413) were correlated with fibrosis severity, as determined by elastography (Supplementary Table S4 and Figure S2). Let-7f-5p was correlated with various fibrosis-linked parameters, such as decreasing albumin levels (r = −0.2031) and platelet counts (r = −0.3778), and to the fibrosis-scores Fib-4 (r = 0.3215), APRI (r = 0.2820), and PRTA-score (r = 0.4332), suggesting its association with hepatic fibrosis severity. As expected, miRNA-122-5p was strongly associated with AST (r = −0.2625) and ALT (r = −0.4093) levels, and thus marks hepatocyte damage. miRNA-142-5p (r = −0.1602), Let-7f-5p (r = 0.1416), and miRNA-122-5p

(r = 0.2628) were associated with age, while Let-7f-5p (r = −0.1563) and miRNA-29a-3p (r = −0.2161) were associated with body mass index (Table 2).

**Figure 4.** Evidence of significant liver fibrosis by the plasma levels of individual miRNAs. Expression analysis of circulating miRNAs in patients (*n* = 208) with chronic alcohol abuse, viral infection, and non-alcoholic fatty liver disease (NAFLD), with (F2–4) or without (F0–1) significant liver fibrosis. *p*-values were calculated using the Mann–Whitney U-test. Data is presented as Tukey boxplots. Receiver operating characteristic curve analysis was performed, and area under the curve (AUC) values were calculated to quantify the diagnostic value. The discriminative capacity of (**A**) candidate miRNAs was compared to (**B**) miRNA-122-5p and (**C**) miRNA-29a-3p and to (**D**) the serological scoring algorithms Fib-4, APRI, AST/ALT, and PRTA.
