AimTo observe the effect of pioglitazone on serum retinol binding protein 4 (RBP4) and omentin 1 in type 2 diabetes mellitus patients.Methods80 cases with type 2 diabetes mellitus were randomly divided into two groups: placebo group and pioglitazone group, 40 cases in each group, for a period of 3 months.Levels of fasting blood glucose, insulin resistance index (HOMA-IR), serum RBP4 and omentin 1 before and after treatment were compared in the two groups.ResultsCompared with placebo group, fasting blood glucose and HOMA-IR in pioglitazone group were obviously decreased after treatment (p<0.05), the level of serum RBP4 was decreased (p<0.01), but omentin 1 was increased (p<0.01).Pearson correlation analysis showed that RBP4 was positively correlated with FPG, BMI and HOMA-IR, but negatively correlated with LDL (p<0.05).Omentin 1 was positively correlated with LDL, but negatively correlated with FPG, BMI and HOMA-IR (p<0.05).ConclusionPioglitazone can improve insulin resistance through the regulation of serum RBP4 and omentin 1 level.