The non-thyroidal illness syndrome is associated with postoperative surgical site infections in enterocutaneous fistulae.

Background: Non-thyroidal illness syndrome (NTIS) is common in critically ill patients and associated with adverse outcomes. Many enterocutaneous fistula (ECF) patients still suffer NTIS prior to definitive surgery. This study was designed to explore the association between preoperative NTIS and postoperative outcomes in ECF patients.

Methods: A total of 264 ECF patients who underwent definitive surgery from April 2014 to November 2016 were studied. Thyroid hormones were tested for each patient before surgery, and the patients were divided into two groups (NTIS group and euthyroid group) according to the presence of NTIS. Demographics, surgery-related data, and complications during the first 30 days after surgery were recorded and analyzed.

Results: Among ECF patients accepted for definitive surgery, the prevalence of NTIS was 31.4% (83/264). The most common presentation of NTIS was a single low free triiodothyronine (FT3) 28.0% (74/264), followed by low FT3 combined with low thyrotropin (TSH) 1.9% (5/264), and low free thyroxine (FT4) combined with low TSH 1.5% (4/264). Compared to the euthyroid group, more patients with NTIS had multiple ECF, received more than three months of enteral nutrition pre-operatively, and developed surgical site infections (SSI). FT3 levels correlated with risk of SSI. Receiver operating characteristic curve (ROC) analysis revealed the diagnostic effectiveness of FT3, suggesting that the optimal cut-off value was 3.5 pmol/L. Area under the curve, sensitivity and specificity were 0.75, 72.6% and 68.7%, respectively.

Conclusions: ECF patients with NTIS before definitive surgery appear to have a greater risk for poor outcomes. The benefit of thyroid hormone replacement therapy or delaying definitive surgery deserves further study.