Nonthyroidal illness syndrome (NTIS) is prevalent in critical illness; it is associated with poor outcomes. However, few studies have focused on the relationship between NTIS and short bowel syndrome (SBS). The aim of this study was to investigate the incidence, etiology, and prognosis of NTIS and its correlation in clinical variables in adult patients with SBS.

Nonthyroidal illness syndrome (NTIS), also known as euthyroid sick syndrome or low triiodothyronine (T3) syndrome, is a condition characterized by decreased serum concentrations of T3 and low or normal plasma concentrations of thyroxine (T4) without a compensatory increase in the serum levels of thyroid stimulating hormone (TSH). However, such typical changes differ from those in primary or secondary thyroid disorders. NTIS refers to distortions in thyroid function without thyroid disease caused by various critical illnesses. This condition has been described in different acute and chronic disease states over the past 30 years, including sepsis, starvation, trauma, burns, myocardial infarction, Crohn's disease, enterocutaneous fistulas, chronic kidney disease, and major surgery.

Short bowel syndrome (SBS), the most common form of intestinal failure, is a rare condition resulting from the loss of portions of the intestine, typically because of extensive surgical resection or loss of intestinal function. Patients with SBS often stuffer from intestinal insufficiency or intestinal failure because they are unable to maintain fluid and nutrient balances on a normal diet. Therefore, SBS can cause various metabolic and physiologic disturbances, many of which are associated with growth, intestinal adaptation, and hormone secretion. Many previous studies of SBS have evaluated growth hormone, glucagon-like peptide-1, glucagon-like peptide-2, vitamin D and parathyroid hormone, peptide YY, and ghrelin. However, few studies have reported the association between SBS and the hypothalamic-pituitary-thyroid axis and its balance.

The present study was performed to evaluate the association of thyroid hormone disturbance and SBS in adult patients. Because NTIS is the main type of thyroid hormone disturbance, we further investigated the incidence, underlying mechanisms, and correlation with clinical variables and prognosis of NTIS in adult patients with SBS.

Inclusion Criteria:

(1) Adult patients with SBS, defined as intestinal malabsorption disorder resulting from extensive bowel resection with a remnant small intestine length of greater than 200 cm, admitted to a clinical nutrition center.

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Exclusion Criteria:

1. age less than 18 years;
2. previous history of thyroidal, hypophyseal or hypothalamic disease;
3. lactational or gestational period;
4. medication history of thyroidal hormone or antithyroid drugs;
5. craniocerebral injury;
6. attack of coronary heart disease, myocardial, or cerebral infarction in the past month;
7. intracranial infection or hemorrhage in the past month. -

Patients with SBS admitted to a clinical nutrition center in a tertiary referral hospital were identified to evaluate the incidence of NTIS and to explore its correlation with clinical variables and prognosis in adult patients.