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 < or = 78 ng dL(-1) (1.2 nmol 
L(-1)) (median) were characterized as 'low T3'. Cases with T4 values < or = 4.66 
microg 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 < or = 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%, chi(2) = 12.09, P < 0.001, odds ratio (OR) = 0.53, 95% 
confidence interval (CI) 0.37-0.76]. Cox regression analysis revealed that 
increased age, haemorrhagic stroke, low Scandinavian Stroke Scale score, 
increased glucose and low T3 values (hazards ratio 0.69, CI = 0.48-0.98, P = 
0.041) were significant predictors of 1-year mortality.
CONCLUSIONS: A high proportion of patients with acute stroke were found soon 
after the event with low T3 values. The low-T3 syndrome is an independent 
predictor of early and late survival in patients with acute stroke, and predicts 
handicap at 1 year.