Correlation between a low serum free triiodothyronine level and mortality of severe pulmonary tuberculosis patients

This study aimed to assess the relationship between a low serum free triiodothyronine (FT3) level and the mortality of severe pulmonary tuberculosis (TB) patients.

We performed a retrospective study and reviewed the medical records of patients with severe pulmonary TB between January 2016 and June 2022. The patient demographics, Acute Physiology and Chronic Health Evaluation (APACHE) II score, survival or death at 28 and 90 days after hospital admission, and serum FT3 level were recorded. Bivariate regression analysis was performed to study the relationship between mortality and the FT3 level. The Kaplan-Meier method and the log-rank test were used to compare the survival rates between patients with different serum FT3 levels.

Our study included 495 severe pulmonary TB patients, with 383 (77.4%) patients having a low serum FT3 level. The low-serum FT3 group had high 28-day and 90-day mortalities. The patients who had died by 28 or 90 days after hospital admission had a low FT3 level. Survival analysis showed that the patients with a low serum FT3 level had a low probability of survival at 28 days and at 90 days after hospital admission.

The serum FT3 level was correlated with the 28-day and 90-day mortalities in patients with severe pulmonary TB. The serum FT3 level should be monitored in these patients to help manage their disease.