Objective:

To investigate the association between the fibrosis-4 (FIB-4) index and diabetes-related vascular complications in patients with type 2 diabetes mellitus (T2DM), with carotid atherosclerosis (CAS) as the primary outcome and lower extremity arterial disease (LEAD) and diabetic peripheral neuropathy (DPN) as secondary outcomes.

Approach:

• Study Design: Cross-sectional study involving 1,045 patients with T2DM.
• Statistical Analysis: Logistic regression models assessed associations between FIB-4 and risks of CAS, lower extremity arterial disease (LEAD), and diabetic peripheral neuropathy (DPN).
• Additional Analyses: Restricted cubic spline analyses evaluated nonlinear relationships; ROC curves determined FIB-4's discriminatory performance.

Key Findings:

• Higher FIB-4 levels were associated with increased odds of CAS (OR: 1.16, 95% CI: 0.79–1.72; OR: 1.75, 95% CI: 1.19–2.58; OR: 2.04, 95% CI: 1.39–3.00 for the second, third, and fourth FIB-4 quartiles, respectively).
• RCS analysis indicated a nonlinear association between FIB-4 and CAS risk.
• FIB-4 showed limited discriminatory performance for CAS (AUC = 0.579).
• Similar but weaker associations were found for LEAD (AUC = 0.587) and DPN (AUC = 0.532).

Interpretation:

Elevated FIB-4 is significantly associated with higher risks of CAS and LEAD in T2DM patients, with the strongest association observed for CAS.

Limitations:

• Cross-sectional design limits causal inference.
• Limited generalizability to populations outside of the study cohort.

Conclusion:

Elevated FIB-4 is significantly associated with higher risks of CAS and LEAD in T2DM patients.