The effect of thyroid function on the risk of psychiatric readmission after hospitalization for major depressive disorder.

The relationship between thyroid function and depression has long been recognized, but little is known about the effect of thyroid function on the risk of readmission after hospitalization for major depressive disorder (MDD). This retrospective cohort study was aimed to explore the effect of thyroid function on psychiatric readmission after hospitalization for MDD. Data was derived from electronic medical records (EMR) of the Shanghai Mental Health Center (SMHC), Shanghai, China. Univariate and multivariate logistic regression analyses were conducted in subjects aged ≥ 18 years who had been hospitalized for MDD between January 1, 2007, and May 31, 2019. Of the 1803 eligible patients, 85 and 132 patients experienced psychiatric readmission within 90 days and 180 days after discharge respectively. Multivariate analyses showed that serum FT3 level (aOR=1.271; 95%CI=1.051-1.537) and comorbidity of thyroid disease (aOR=2,179; 95%CI=1.136-4.179) was independently associated with the risk of 90-day and 180-day readmission respectively. These findings indicated that high serum FT3 levels and comorbidity of thyroid disease could increase the risk of readmission after hospitalization for MDD. It is warranted to provide routine assessment and intervention of the thyroid function during the treatment of depression so as to prevent re-hospitalization.