We did not detect interaction effects in our sample between opioid use and liver fibrosis (sCD14, p = 0.258; IL-6, p = 0.341; D-dimer, p = 0.158) or concomitant hepatitis C (sCD14, p = 0.94; IL-6, p = 0.585; D-dimer, p = 0.932) and concomitant hepatitis B (sCD14, p = 0.702; IL-6, p = 0.781; D-dimer, p = 0.867) on the concentration of biomarkers studied. The gene discussed is IL6; the disease is hepatitis C virus infection.