Relationship of admission thyroid function tests to outcome in critical illness

One hundred and eighty patients had serum thyrotropin, total triiodothyronine and free thyroxine concentrations measured within 3 h of admission to the Intensive Therapy Unit to assess whether thyroid function tests could predict outcome in critical illness. Overall mortality was 30.6%. Nonsurvivors were older (p = 0.001), and had higher APACHE II scores (p < 0.001) and predicted mortalities (p < 0.001). There was no difference in the median values of thyrotropin, total triiodothyronine and free thyroxine concentrations between survivors and nonsurvivors. Thyrotropin concentration was subnormal in 15 patients, normal in 152 and elevated in 13 patients. In contrast, 80 patients had subnormal triiodothyronine concentration. Free thyroxine was subnormal in five patients. Thyrotropin, total triiodothyronine and free thyroxine concentrations were not related to outcome (p = 0.360, p = 0.622, p = 0.726, respectively). No variable independently predicted death. Total triiodothyronine concentrations were lower in patients who received dopamine before admission to the intensive therapy unit than those who did not (p = 0.008); thyrotropin and free thyroxine concentrations were not influenced by dopamine administration. Serum concentrations of thyrotropin, total triiodothyronine and free thyroxine measured within 3 h of admission to the intensive therapy unit are not predictive of outcome.