Estimated glucose disposal rate and severe abdominal aortic calcification: evidence from a nationally representative study with external validation.

Background: Estimated glucose disposal rate (eGDR) is a validated surrogate marker of insulin resistance and has been associated with cardiometabolic risk. However, its relationship with abdominal aortic calcification (AAC) remains incompletely understood, and evidence from independent populations is limited. Methods: We analyzed data from 2,994 adults aged ≥20 years in the National Health and Nutrition Examination Survey (NHANES) 2013-2014. An independent external validation cohort including 745 participants was used to confirm the findings. Severe AAC was defined using the Kauppila scoring system. Multivariable logistic regression models were applied to evaluate the association between eGDR and severe AAC. Dose-response relationships were assessed using restricted cubic spline models, and subgroup analyses were performed to explore potential effect modification. Results: Lower eGDR levels were significantly associated with higher odds of severe AAC in both the NHANES cohort (fully adjusted OR per 1-unit increase: 0.82; 95% CI: 0.75-0.90) and the validation cohort (OR: 0.79; 95% CI: 0.69-0.91). Participants in the highest eGDR tertile had substantially lower odds of severe AAC compared with those in the lowest tertile in both cohorts. Restricted cubic spline analyses demonstrated an approximately linear inverse association between eGDR and severe AAC, with no evidence of nonlinearity. Similar findings were observed in the external validation cohort. Subgroup analyses showed consistent associations across most population strata. Conclusion: Lower eGDR is independently and linearly associated with a higher prevalence of severe AAC. These findings, validated in an independent cohort, support the potential utility of eGDR as a simple and accessible marker for identifying individuals at increased risk of vascular calcification.