Low triiodothyronine: A new facet of inflammation in acute ischemic stroke

•fT3 is associated with inflammation in AIS.•fT3 is correlated with stroke severity of AIS.•Thyroid dysfunction is implicated in the pathogenic pathway in AIS.

BackgroundPatients with acute ischemic stroke (AIS) frequently experience low free triiodothyronine (fT3) concentrations. Inflammation is recognized as a key contributor to the pathophysiology of stroke. Previous studies, however, did not simultaneously evaluate fT3 and inflammation biomarkers in AIS patients.MethodsMarkers of inflammation, including serum concentrations of C-reactive protein (CRP) and albumin, and fT3 were assessed retrospectively in 117 patients. Stroke severity was measured on the National Institutes of Health Stroke Scale (NIHSS). Regression analyses were performed to adjust for confounders.ResultsSerum fT3 concentrations were significantly lower in moderate AIS patients than those in mild AIS patients (P < 0.001). fT3 concentration also positively correlated with serum albumin concentration (r = 0.358, P < 0.001) and negatively correlated with log10CRP concentration (r = − 0.341, P < 0.001), NIHSS score (r = − 0.384, P < 0.001). Multiple regression analysis showed that CRP, albumin concentrations and NIHSS score were independently correlated with fT3 concentration. Binary logistic regression analysis showed that fT3 concentration was an independent factor correlated with NIHSS score, the area under the receiver operating characteristic curve was 0.712 (95% CI, 0.618–0.805).ConclusionsLow fT3 concentrations may be involved in the pathogenic pathway linking inflammation to stroke severity in AIS patients.