RBP4 and fibrosis: However, RBP4 levels were significantly lower in patients with severe liver fibrosis (n = 42) than in those with no or mild fibrosis (n = 109) (SMD: −1.42; 95% CI: −2.53, −0.30; p = 0.01), suggesting a potential association between RBP4 and liver fibrosis in patients with HCV.