AIM: To investigate the correlation between serum levels of secreted frizzled-related protein-4(SFRP-4), chitinase 3-like protein 1(CHI3L1)and diabetic retinopathy(DR)in patients with type 2 diabetes mellitus.

METHODS: Prospective study. A total of 103 DR patients who admitted to our hospital from October 2018 to October 2023 were selected as DR group, including 39 cases of early DR, 42 cases of mid DR, and 22 cases of late DR; 98 patients with simple type 2 diabetes were selected as DM group, 101 healthy individuals were selected as the control group, and baseline data and clinical indicators were collected. Enzyme linked immunosorbent assay(ELISA)was applied to detect serum levels of SFRP-4 and CHI3L1.

RESULTS: The levels of serum SFRP-4, CHI3L1, triglyceride(TG), low-density lipoprotein cholesterol(LDL-C), glycated hemoglobin(HbA1C), fasting plasma glucose(FPG), homeostasis model assessment of insulin resistance(HOMA-IR)in the DR group were higher than those in the DM group and the control group(all P<0.05); the serum levels of SFRP-4, CHI3L1, TG, LDL-C, HbA1C, FPG, HOMA-IR in the DM group were higher than those of the control group(all P<0.05). The course of disease, TG, LDL-C, HbA1C, FPG, HOMA-IR, SFRP-4, and CHI3L1 of late stage of DR were higher than those in the middle and early stages of DR(all P<0.05). The serum levels of SFRP-4 and CHI3L1 in DR patients were positively correlated with disease course, TG, LDL-C, HbA1C, FPG, HOMA-IR and DR staging(all P<0.05). The area under the curve(AUC)of serum SFRP-4, CHI3L1, and combined diagnostic DR was 0.809, 0.801, and 0.898, respectively. SFRP-4 and CHI3L1 were independent risk factors of DR(P<0.05).

CONCLUSION: The levels of serum SFRP-4 and CHI3L1 are closely related to DR in patients with type 2 diabetes. The higher levels of SFRP-4 and CHI3L1 suggested that patients have a higher risk of DR.