Nonthyroidal Illness Syndrome in

Introduction: Aim: To evaluate the prevalence of nonthyroidal illness syndrome (NTIS) in hospitalized patients with CDI and its impact on the length of hospitalization and patient survival. Methods: A retrospective single-center study at a hospital in the Subcarpathian region of Europe. We reviewed the medical data of 370 patients with confirmed CDI who stayed at the hospital between January 1, 2015, and April 1, 2024. Demographic data, laboratory values, comorbidities, treatments, and clinical outcomes were also collected. We independently compared the data of patients with NTIS and euthyroidism and independently between survivors and nonsurvivors. The statistical test used were Mann-Whitney U-test and Chi-square test (with Pearson's or Yates' correction). Results: Of 370 patients, 113 (30%) were included in the study. Eighty-one (71.7%) patients presented with CDI accompanied by NTIS. The median age in both the CDI and NTIS groups was 82 years, and 51.8% of patients were female. NTIS was significantly associated with 3.7-fold higher odds of death compared to euthyroidism (odds ratio = 3.70; 95% confidence interval: 1.02-13.38; Conclusions: Low serum FT3 levels appear to be an independent marker of clinical deterioration and a predictor of mortality in patients with CDI and could be incorporated into the prognostic assessment of these patients.