Association of systemic immune-inflammation index (SII) and aggregate index of systemic inflammation (AISI) with thyroid nodules in patients with type 2 diabetes mellitus: a retrospective study

Objective This retrospective study aimed to investigate the association between TNs and the systemic immune-inflammation index (SII) and the aggregate index of systemic inflammation (AISI) in patients with T2DM. Methods A total of 370 T2DM patients, who were admitted to Dongzhimen Hospital between January 2020 and March 2023, were included in this retrospective study. Binary logistic regression models with multivariable adjustment were employed to assess the relationship between SII, AISI quartiles, and TNs. Furthermore, receiver operating characteristic (ROC) curve analysis was performed to assess the diagnostic accuracy of SII and AISI in identifying T2DM patients with TNs. Results Age, diabetes duration, diabetic nephropathy (DN), SII, and AISI demonstrated significant positive associations with TNs. Compared to the first quartile of SII, the second, third, and fourth quartiles showed increased risks of TNs with hazard ratios (HRs) of 1.578 (0.883–2.820), 2.279 (1.257–4.131), and 3.626 (1.931–6.810), respectively (P < 0.001). Similar results were observed for AISI and TNs. ROC curve analysis revealed that SII and AISI exhibited a high discriminatory capability for identifying TNs in the overall and male participant group, whereas the significance among females was not discernible. Conclusions This study provides evidence that SII and AISI are independent risk factors for TNs, suggesting that elevated SII and AISI levels may contribute to the development of TNs in patients with T2DM particularly among male individuals.