Association of systemic Immune-inflammation Index with Severity of Diabetic Foot Ulcers: a Cross-sectional Study in Karachi

Abstract

Objective: This study attempted to explore the relationship between Systemic immune-inflammation index (SII) and severity of Diabetic foot ulcer (Wagner grades I-V) and compared the discriminating power of SII with HbA1c. Diabetic foot ulcer (DFU) is a serious complication of Type 2 diabetes, caused by neuropathy, ischemia, infection and chronic inflammation. Systemic immune-inflammation index is a combination of three hematological parameters reflecting innate immunity, adaptive regulation and thrombosis. SII is used to predict outcomes in cancer and cardiovascular disease, but its association with severity of DFU is not established.Methods: The study design was analytical cross-sectional study, carried out in two tertiary care hospitals of Dow University of Health Sciences (DUHS) during June to November 2024. We enrolled 100 adults with type 2 diabetes and DFU. Data on demographics, HbA1c, and complete blood counts were collected. The severity of DFU was estimated according to the Wagner classification and SII was calculated. Descriptive statistics, correlation tests, trend analysis, multiple linear regression forhospital stay and ROC curves of severe DFU (Wagner 3) were conducted.Results: The results showed that SII levels are significantly higher as the Wagner grade increases (p<0.001) and were moderately correlated with the ulcer severity (r=0.573, p<0.001). SII showed weak correlation with HbA1c (r=0.234, p=0.019). The ROC analysis showed that SII could discriminate between severe DFU (0.851, good) more than HbA1c (0.739, fair). SII was a positive predictor of longer hospital stay (p=0.001) in regression analysis, and a negative association between infection and hospital stay was observed.Conclusions: SII is highly correlated with the severity of DFU and has a greater discriminative power than HbA1c. SII can be used in low-resource areas to s