Coronary heart disease (CHD) is one of the major public health burdens in the world. Although treatment strategies have been developed, but CHD remains a leading cause of morbidity and mortality worldwide. The diagnosis of CHD mainly relies on coronary angiography or contrast-enhanced computed tomography. However, due to the lack of equipment in primary hospitals, early diagnosis and prognosis judgment are relatively difficult. Therefore, the search for relatively simple and easy-to-obtain laboratory indicators is conducive to providing basis for primary care physicians to diagnose and treat CHD.

To investigate the correlation of serum interleukin-6 (IL-6) and fasting blood glucose (FPG) levels with the degree and clinical classification of coronary stenosis, number of lesions and adverse cardiovascular events in patients with CHD.

CHD patients admitted to the Fifth Affiliated Hospital of Xinjiang Medical University from September to November 2020 were included as the study objects, and their general data and laboratory test results were collected. According to Gensini score criteria, the patients were divided into the mild stenosis group (group A, Gensini score≤33.25 points, n=40) and moderate and severe stenosis group (group B, Gensini score>33.25 points, n=40) based on the Gensini scoring criteria. According to the results of coronary angiography results, patients were divided into the single-vessel lesion group (n=28), double-vessel lesion group (n=21) and multi-vessel lesion group (number of lesion branch≥3, n=31) based on the number of lesions. According to the clinical classification, patients were divided into stable angina group (n=34) and acute coronary syndrome group (n=46). Spearman rank correlation analysis was used to explore the relationship of serum IL-6, FPG with relevant data of patients. Survival curves of patients were plotted using the Kaplan-Meier method, and the comparison of survival curves was performed by Log-rank test. Univariate and multivariate Cox proportional hazard regression analyses were used to explore the factors influencing the risk of adverse cardiovascular events in patients with CHD. The receiver operating characteristic (ROC) curve of IL-6 predicting the occurrence of adverse events was plotted.

IL-6 and FPG in group A were lower than those in group B, IL-6 in the multi-vessel lesion group was higher than that in the single-vessel lesion group, FPG was higher than that in double-vessel lesion group, and IL-6 and FPG in acute coronary syndrome group was higher than that in stable angina group, with statistical significance (P<0.05). Spearman rank correlation analysis showed that serum IL-6 was correlated with clinical type, number of coronary lesions, Gensini score, gender, triglyceride (TG) and FPG, and FPG was correlated with clinical type, number of coronary lesions, Gensini score, age and IL-6 (P<0.05). The patients were divided into IL-6>45.8 ng/L group (n=39) and IL-6≤45.8 ng/L group (n=41) according to the median IL-6 expression level (45.8 ng/L), and the upper limit of normal FPG (6.1 mmol/L) was used as the grouping standard to divide the patients into FPG>6.1 mmol/L group (n=36) and FPG≤6.1 mmol/L group (n=44). Log-rank test results showed that the incidence of adverse cardiovascular events in IL-6>45.8 ng/L group was higher than that in IL-6≤45.8 ng/L group (76.9% vs. 36.6%; χ²=16.075, P < 0.001), FPG>6.1 mmol/L group had a higher incidence of adverse cardiovascular events than FPG≤6.1 mmol/L group (69.4% vs. 45.5%; χ²=4.292, P=0.038). Multivariate Cox proportional hazard regression analysis showed that IL-6 was a significant factor in adverse cardiovascular events in patients with CHD (HR=2.396, 95%CI=1.203-6.054, P<0.05). The area under ROC curve of IL-6 for predicting adverse cardiovascular events was 0.769 (95%CI=0.658-0.880), the best optimal value was 40.97 ng/L, with the sensitivity and specificity of 0.867 and 0.683.

Serum IL-6 and FPG levels are associated with CHD and its poor prognosis. Serum IL-6 is an independent risk factor for adverse cardiovascular events in patients with CHD.