Abstract: Objective To study the diagnostic value of detection of retinol-binding protein 4(RBP4), glycated hemoglobin(HbA1c) and microRNA(miRNA)-1-3p levels in patients with ST-segment elevation myocardial infarction(STEMI) and their relationship with the disease severity. 
Methods A total of 136 STEMI patients admitted to the Second Hospital of Baoding City were selected as STEMI group, and divided into three subgroups according to SYNTAX score:mild lesion group(n=55), moderate lesion group(n=43) and severe lesion group(n=38). Anther 65 healthy people who underwent physical examination during the same period were selected as the control group. Clinical data of the study subjects were collected. Serum RBP4 and HbA1c levels were measured by enzyme-linked immunosorbent assay, and serum miR-1-3p levels were measured by quantitative real-time polymerase chain reaction(qRT-PCR). Spearman′s correlation coefficient analysis was used to analyze the correlation of STEMI serum RBP4 and HbA1c with miR-1-3p levels and SYNTAX score. Multivariate logistic regression analysis was used to analyze the risk factors for the development of STEMI. Receiver operating characteristic(ROC) curve was used to analyze the diagnostic value of serum RBP4, HbA1c and miR-1-3p levels for STEMI. 
Results Compared with the control group, the STEMI group had an increased proportion of smoking history and increased levels of total cholesterol, triglycerides, low-density lipoprotein cholesterol(LDL-C), C-reactive protein(CRP), RBP4, HbA1c, and miR-1-3p and decreased levels of high-density lipoprotein cholesterol(HDL-C)(t/Z=2.459-9.608, all P＜0.05). Serum RBP4, HbA1c and miR-1-3p levels were sequentially increased in the mild, moderate and severe lesion groups(F=18.202-48.798, all P＜0.001). STEMI serum RBP4, HbA1c and miR-1-3p levels were positively correlated with SYNTAX scores(r=0.588-0.647, all P＜0.001). Smoking history, CRP, LDL-C, RBP4, HbA1c and miR-1-3p were independent risk factors for the development of STEMI(OR= 1.037-1.646, all P＜0.05). The area under the ROC curve of the combined detection of serum RBP4, HbA1c and miR-1-3p for the diagnosis of STEMI was higher than that of each indicator alone (Z=3.025-4.213, all P＜0.05). 
Conclusion Elevated levels of serum RBP4, HbA1c and miR-1-3p in STEMI patients are positively correlated with the degree of coronary artery lesion, which can be used as diagnostic indicators of STEMI.

Key words: T-segment elevation myocardial infarction, retinol-binding protein 4, glycated hemoglobin