Our findings indicate a statistical association between a lower FT3/FT4 ratio and increased odds of iSAP, even after adjusting for demographic factors (e.g., age, sex), vascular comorbidities (e.g., smoking, hypertension, diabetes mellitus, atrial fibrillation, COPD), and key laboratory parameters (e.g., FPG, HDL-C, LDL-C, CRP, BUN, UA, HCY, WBC, eGFR, HbA1c, TG, AST) in multivariate models. The gene discussed is CRP; the disease is atrial fibrillation.