A Composite Score of Insulin Resistance and Inflammation Biomarkers for Predicting Lower Limb Complications in Type 2 Diabetes Mellitus

Diabetes mellitus (DM) is a chronic non-communicable disease associated with macroangiopathy and microangiopathy, with disabling or even life-threatening complications. In the present study, we aimed to analyze the association between insulin resistance (IR) and inflammation biomarkers and peripheral arterial disease (PAD) and diabetic peripheral neuropathy (DPN), respectively. The study had a cross-sectional design and evaluated a panel of IR related indices and inflammatory biomarkers commonly used in clinical and epidemiological research, including the triglyceride-glucose (TyG) index and its obesity related derivates, cholesterol, HDL, glucose (CHG) index, lipid-derived ratios, and composite inflammatory indices, together with interleukin-6 (IL-6), tumor necrosis factor alpha (TNFα) and C-reactive protein (CRP) in 110 subjects, according to the presence or absence of PAD and DPN, respectively. In the PAD (+) group, TyG-waist-to-height-ratio (TyG-WHtR) and CHG recorded significantly increased values (<i>p</i> = 0.042, respectively <i>p</i> < 0.001), compared to PAD (-). CHG recorded significantly increased values in DPN (+) subjects (<i>p</i> = 0.007). In addition, in the PAD (+) subjects, IL-6 and systemic immune inflammation index (SII) recorded significantly increased values (<i>p</i> = 0.026, respectively, <i>p</i> = 0.015) and TNFα, monocyte to lymphocyte ratio (MLR) and C-reactive protein to albumin ratio (CAR) recorded significantly increased values in DPN (+) subjects (<i>p</i> = 0.028, respectively, <i>p</i> = 0.008, and <i>p</i> = 0.038). We developed a score with a good discriminatory performance for PAD and DPN, including DM duration, TyG-WHtR, SII, MLR and CAR (AUROC 0.822 in PAD, respectively 0.848 in DPN, <i>p</i> < 0.001). A composite score combining IR and inflammatory biomarkers showed strong discriminatory performance for lower limb complications in type 2 diabetes, suggesting a valuable tool for early detection and prevention.