Euthyroid sick syndrome predicts the risk of ischemic stroke-associated pneumonia in the acute stage of ischemic stroke: a nested case-control study.

Objective: Ischemic stroke-associated pneumonia (iSAP) affects about 10% of acute ischemic stroke patients during hospitalization. Current prediction scales for iSAP are insufficient. Identifying early biomarkers for stroke-associated pneumonia is crucial for improving patient outcomes. This study aimed to investigate the predictive value of euthyroid sick syndrome (ESS) for iSAP in acute-stage of ischemic stroke patients. Methods: We studied 1767 acute ischemic stroke patients within one week of symptom onset, categorizing them into an infection group (iSAP, n=376) and control group (control, n=1391). COX regression analysis was used to identify the potential risk and protected factors. Kaplan-Meier time-event curves and Log-Rank tests were performed to differentiate infection time in patients with ESS or normal T3 group. Results: The iSAP group had higher rates of risk factors like older age, atrial fibrillation, COPD, and ESS, along with elevated levels of WBC, CRP,and FT4 levels (all P < 0.001). Conversely, iSAP patients had lower GCS scores, eGFR, TSH, T3, FT3 (all P < 0.001) and T4 levels (P = 0.005) upon admission. No significant differences were observed in sex, smoking history, hypertension, diabetes, or LDL-C levels (P > 0.05). COX regression analysis identified age, KWST scores, leukocyte count, CRP, and ESS (all P < 0.001) as significantly correlated with iSAP. ROC analysis revealed ESS as a predictor with sensitivity of 35.64% and specificity of 87.92% for SAP prediction, like atrial fibrillation and higher than COPD and eGFR. Conclusion: ESS at admission predicts a higher risk of stroke-associated pneumonia in acute-stage of ischemic stroke.