Abstract: Objective  To investigate the relationship between serum FT3 level and anxiety state in maintenance hemodialysis (MHD) patients.  Methods  This was a single-center and cross-sectional study. Patients who underwent MHD in our center in September 2021 were enrolled. Demographic data, routine blood biochemical examination, and serum free triiodothyronine (FT3) before dialysis sessions were tested, and the anxiety status of the patients was evaluated by the Hamilton Anxiety Scale (HAMA). According to the anxiety scale score, patients were divided into the without anxiety status group (total score＜7 points) and with anxiety status group (total score≥7 points). Multivariate binary Logistic regression was used to analyze the independent factors associated with anxiety risk, and software (Empower Stats 3.0) was used to analyze causal mediating effects among variables.  Results  A total of 120 MHD patients were enrolled in this study, including 66 patients in the anxiety status group and 54 patients in the control group. Spearman analyses showed that the levels of serum FT3 negatively correlated with the sleep score (r=-0.277, P=0.002). Multivariate binary logistic regression analysis showed that low serum FT3 level in MHD patients in our center was independent associated with anxiety status (OR=3.167，95% CI：1.144～8.772, P=0.027), but when sleep score was included in the models, the association between the serum FT3 and anxiety status disappeared (OR=0.842，95% CI：0.812～8.051, P=0.109). Mediation analysis showed that 47.6% of the effect of serum FT3 on anxiety state was mediated through sleep disturbance (P=0.004).

Key words: Maintenance hemodialysis, Serum low free triiodothyronine, Anxiety, Sleep