Low Free Triiodothyronine Predicts 3-Month Poor Outcome After Acute Stroke

Abstract

Background and PurposeThe association between thyroid hormone levels and long-term clinical outcome in patients with acute stroke has not yet been thoroughly studied. The purpose of the present study was to test the hypothesis that thyroid hormone levels are associated with 3-month functional outcome and mortality after acute stroke. MethodsWe retrospectively analyzed 702 consecutive patients with acute stroke (251 women; median age, 73 years) who were admitted to our department. General blood tests, including thyroid stimulating hormone (TSH), free triiodothyronine (FT3), and free thyroxine (FT4), were performed on admission. Neurological severity was evaluated using National Institutes of Health Stroke Scale (NIHSS) scores on admission and modified Rankin Scale (mRS) scores at 3 months after stroke onset. Poor outcome was defined as an mRS score of 3-5 or death. The impact of thyroid function on 3-month outcome was evaluated using multiple logistic regression analysis. ResultsPoor functional outcome was observed in 295 patients (42.0%). Age (P < .0001), female sex (P < .0001), admission NIHSS score (P < .0001), smoking (P = .0026), arterial fibrillation (P = .0002), preadmission mRS (P < .0001), estimated glomerular filtration rate (P = .0307), and ischemic heart disease (P = .0285) were significantly associated with poor functional outcome, but no relationship between FT4, TSH, and poor functional outcome was found. A multivariate logistic regression analysis showed that low FT3 values (<2.00 pg/mL) were independently associated with poor functional outcome (odds ratio [OR], 3.16; 95% confidence interval [CI], 1.60-6.24) and mortality (OR, 2.55; 95% CI, 1.33-4.91) at 3 months after stroke onset. ConclusionsOur data suggest that a low FT3 value upon admission is associated with a poor 3-month functional outcome and mortality in patients with acute stroke.