Diagnostic Accuracy and Cut-off Values of Atherogenic Lipid Indices for Identifying Elevated HbA1c in Adults

Atherogenic dyslipidemia, characterized by elevated triglyceride (TG) levels and reduced high-density lipoprotein cholesterol (HDL-C), is closely associated with insulin resistance and an unfavorable cardiometabolic profile. The atherogenic index of plasma (AIP), calculated as the logarithm of the TG-to-HDL-C ratio, integrates these lipid parameters into a single indicator of atherogenic risk. This study aimed to evaluate the discriminatory performance of AIP and other lipid parameters in distinguishing individuals with HbA1c >6.5% from those with HbA1c ≤6.5%. The supplied study results included 200 adults divided into two equal groups according to HbA1c: 100 participants with HbA1c ≤6.5% and 100 with HbA1c >6.5%. Lipid measurements were obtained after a 12-hour fast. Receiver operating characteristic (ROC) analysis and the Youden index were used to assess discrimination and identify cut-off values. Mean age was 45.26 ± 10.71 years; 59% were female. AIP had the highest reported area under the ROC curve (AUC = 0.825, 95% CI: 0.765–0.883; p < 0.001). The reported optimal AIP cut-off was >0.145, with 78.0% sensitivity and 74.7% specificity. TG also showed good discrimination (AUC = 0.791, 95% CI: 0.728–0.854; p < 0.001), whereas total cholesterol (AUC = 0.682), LDL-C (AUC = 0.645), and HDL-C (AUC = 0.312) showed weaker or directionally inverse discrimination. Conclusion: This study highlights the potential value of AIP as an adjunctive marker for identifying an atherogenic lipid profile associated with elevated HbA1c. AIP should be interpreted as a complementary cardiometabolic indicator rather than a replacement for established glycemic assessment methods.