Low triiodothyronine: a strong predictor of outcome in acute stroke patients

Background Low triiodothyronine (T3) has been associated with increased short‐term mortality in intensive care unit patients and long‐term mortality in patients with heart disease. The objective of this study was to investigate possible associations of thyroid hormone status with clinical outcome in patients admitted for acute stroke. Materials and methods A total of 737 consecutive patients with acute first ever stroke who presented within 24 h from symptoms’ onset were studied. Total T3, thyroxin (T4) and thyroid‐stimulating hormone (TSH) levels were assessed in the morning following admission. Cases with T3 values ≤ 78 ng dL−1 (1·2 nmol L−1) (median) were characterized as ‘low T3’. Cases with T4 values ≤ 4·66 µg dL−1 (60 nmol L−1) were characterized as ‘low T4’. Basic and clinical characteristics, stroke risk factors, and brain imaging were evaluated. Neurological impairment was assessed using the Scandinavian Stroke Scale. Results Four hundred and seventeen (56%) patients had T3 values ≤ 78 ng dL−1 and 320 had normal T3 values. The 1‐year mortality was 27·34% for low T3 and 19·37% for normal T3 cases (P = 0·006). A smaller percentage of patients with low T3 values were independent at 1 year compared to those with normal T3 values [54·2% vs. 68·7%, χ2 = 12·09, P