Correlation between systemic immune-inflammation index and lower extremity vascular disease in patients with type 2 diabetes mellitus

Objective To investigate the relationship between systemic immune-inflammation index (SII) and lower extremity vascular disease in patients with type 2 diabetes mellitus (T2DM). Methods A cross-sectional study was conducted on 390 T2DM patients admitted in our department from January 2013 to January 2024. According to the diagnostic criteria for lower extremity vascular disease in T2DM patients, they were divided into a lower extremity vascular disease group (n=158) and a control group (n=232). General data and results of laboratory tests were compared between the 2 groups. Spearman correlation analysis was used to identify the related factors for lower extremity vascular diseases in T2DM patients. The correlation between SII and lower extremity vascular diseases in T2DM patients was analyzed using the Row Mean Scores and Cochran-Armitage Trend analysis. Multivariate logistic regression analysis was applied to identify the risk factors for lower limb vascular lesions in T2DM patients. Receiver operating characteristic (ROC) curve was plotted to evaluate the diagnostic efficacy of SII for lower extremity vascular disease in the patients. Results Compared with T2DM patients without lower extremity vascular disease, those with lower extremity vascular disease were older, had higher levels of total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), SII, larger proportion of carotid vascular lesions, and increased proportion of no-taking statins. The lower extremity vascular disease in T2DM patients was positively correlated with SII/100 (r=0.429, P<0.001), age (r=0.517, P<0.001), TC (r=0.161, P=0.001), LDL-C (r=0.117, P=0.021), carotid artery lesions (r=0.101, P=0.047), no-taking statins (r=0.266, P<0.001). Logistic regression analysis showed that SII, age, LDL-C, and no-taking statins were the risk factors for lower extremity vascular lesions in T2DM patients (P<0.01). The area under the curve (AUC) value of SII combined with age, LDL-C, and no-taking statins in predicting lower extremity vascular disease in T2DM patients was 0.896. Conclusion SII is not only a risk factor, but also a simple marker for lower extremity vascular disease in T2DM patients, suggesting that inflammatory response plays an important role in the occurrence and development of lower extremity vascular disease in T2DM.