Low free T3 level may predict the severity of acute pancreatitis.

Objectives: To demonstrate that deterioration in thyroid function tests can serve as an indicator of severity and prognosis in acute pancreatitis despite a healthy thyroid gland.

Methods: This study is a retrospective, single-center study. Patients diagnosed with acute pancreatitis between May 2020 and June 2021 were evaluated. Acute pancreatitis was diagnosed and classified according to the 2012 revised Atlanta criteria. Patients were categorized into Non-Thyroidal Illness Syndrome and euthyroid groups and compared in terms of biochemical parameters and scoring systems such as Ranson, Glasgow, Balthazar and BISAP scores.

Results: A total of 152 patients were included in the study. Eighty-three patients (54%) were euthyroid, with free triiodothyronine (T3), free thyroxine (T4), and Thyroid-stimulating hormone (TSH) levels within normal limits. Sixty-nine patients (46%) had Non-Thyroidal Illness Syndrome with low serum free T3 levels and low/normal TSH levels. As expected, free T3 was significantly lower in the Non-Thyroidal Illness Syndrome group than in the euthyroid group (1.5 ± 0.04 vs 2.6 ± 0.04, respectively, p < 0.0001). In the Non-Thyroidal Illness Syndrome group, Ranson score (3.35 ± 0.2 vs 2.11 ± 0.18 p < 0.0001), Glasgow (2.4 ± 0.2 vs 1.3 ± 0.1, p < 0.0001), Atlanta (p = 0.007), and Balthazar (2.1 ± 0.1 vs 1.4 ± 0.1, p = 0.001) scores were significantly higher than euthyroid group.

Conclusion: Non-Thyroidal Illness Syndrome provides insight into the prognosis of acute pancreatitis. Free T3 values are a significant parameter that may indicate the prognosis of acute pancreatitis. We believe that free T3 could be incorporated into an ideal scoring system in a disease such as acute pancreatitis, where early determination of prognosis is known to significantly reduce mortality.