Association between thyroid hormone levels and early neurological deterioration in acute ischemic stroke

BACKGROUND: Acute ischemic stroke (AIS) prognosis is significantly influenced by early neurological deterioration (END). Emerging evidence suggests that thyroid function, particularly free triiodothyronine (FT3) levels and the FT3/FT4 ratio, may play a crucial role in END occurrence. This study aimed to investigate the association between thyroid function parameters and END. METHODS: This study included a total of 1767 AIS patients. Multivariable regression analysis was conducted to assess the associations between FT3, the FT3/FT4 ratio, and other thyroid function parameters with END. Subgroup analyses were performed to explore the potential moderating effects of age, smoking status, and sex on these relationships. The predictive performance of the models was evaluated using receiver operating characteristic (ROC) curves. RESULTS: The FT3 levels (3.66 vs. 4.03 pmol/L, P < 0.001) and the FT3/FT4 ratio (0.28 vs. 0.30, P < 0.001) were significantly lower in the END group compared to the non-END group. Multivariable regression analysis identified a higher FT3/FT4 ratio as an independent protective factor against END (OR = 1.20, 95 % CI: 1.07-1.35, P = 0.0014). Subgroup analyses demonstrated that this protective effect was more pronounced inpatients older than 70 years, and non-smokers. Furthermore, the predictive model incorporating thyroid function parameters demonstrated certain predictive advantages over the CRP-based model (AUC = 0.688 vs. 0.624, P = 0.0036), suggesting its potential utility in predicting early neurological deterioration in AIS patients. CONCLUSIONS: Lower FT3 levels and a reduced FT3/FT4 ratio are significantly associated with a higher risk of END. The FT3/FT4 ratio may serve as a valuable biomarker for risk stratification in AIS patients, underscoring the potential role of thyroid function in stroke management.