Association between thyroid function tests at baseline and the outcome of patients with sepsis or septic shock: a systematic review.

Introduction: The severity of critical illness is associated with various patterns of thyroid hormone abnormalities. We sought to evaluate whether the outcome of patients with, specifically, sepsis or septic shock is associated with the thyroid function tests evaluated at diagnosis or admission in the intensive care unit (ICU).

Methods: We performed a systematic review of relevant studies by searching PubMed.

Results: We included nine studies that all had a prospective cohort design. Seven involved children or neonates, and two involved adults. Mortality was the outcome evaluated in eight studies, while the length of ICU stay was evaluated in the remaining study. In univariate analysis, six of the nine included studies showed that either, free or total, triiodothyronine or thyroxine was lower in the group of patients with sepsis or septic shock who had unfavorable outcome than in those who had favorable outcome. Two other studies showed higher TSH values in the group of patients with unfavorable outcome. No significant relevant findings were observed in the remaining study. Regarding the correlation of sepsis prognostic scoring systems with thyroid function tests, the three studies that provided specific relevant data showed variable findings.

Discussion: Most of the relevant studies identified favor the concept that decreased thyroid function at baseline might be associated with a worse outcome of patients with sepsis or septic shock. Although these findings are not consistent, the role of thyroid function in affecting or merely predicting the outcome of sepsis or septic shock merits further investigation.