RBP4 and Insulin resistance: Although serum RBP4 did not correlate with serum glucose on admission to the ICU, serum RBP4 correlated with the C-peptide (r = 0.305, P = 0.001; Figure 4c), with the insulin resistance as calculated by the HOMA index (HOMA-IR; r = 0.248, P = 0.009; HOMA-S, r = -0.248, P = 0.009; Figure 4d).