Levothyroxine monotherapy versus levothyroxine and selenium combination therapy in chronic lymphocytic thyroiditis

Purpose: New strategies are needed for prevention and treatment of chronic lymphocytic thyroiditis (CLT). This study aimed to assess whether combination of levothyroxine treatment and selenium (Se) supplementation results in improved therapeutic effects in CLT compared with levothyroxine monotherapy.

Methods: An open-label, randomized controlled study was performed in 60 CLT patients assigned to two groups. Levothyroxine group (LT) patients (n = 24) received levothyroxine alone for 3 months; meanwhile, the combination (LTSS) group (n = 36) was administered levothyroxine with selenium yeast capsule. Blood selenium concentrations, anti-thyroid peroxidase (TPO) and anti-thyroglobulin (Tg) antibody levels, and inflammatory cytokine amounts were compared between both groups before and after treatment.

Results: At baseline, similar values were obtained in both groups for all the parameters assessed (p > 0.05). After treatment, significantly increased blood selenium levels (µg/L) [90.05 (80.69, 107.76) vs. 39.64 (29.42, 51.10), p < 0.001] and decreased anti-TPO antibody (23.63 ± 9.31 vs. 32.00 ± 10.41%, p = 0.002), anti-Tg antibody (35.84 ± 15.21 vs. 45.47 ± 14.24%, p = 0.015) and IL-2 amounts (pg/mL) [159.29 (124.54, 189.70) vs. 226.48 (190.74, 266.56), p < 0.001] were observed in the LTSS group compared with the LT group post-treatment; meanwhile, similar IL-10 concentrations [23.14 (21.65, 28.56) pg/mL vs. 24.68 (21.71, 29.67) pg/mL] were obtained in both groups. Subgroup analysis of patients with hypothyroidism showed the same trend observed in the whole population; in patients with normal thyroid function, only Se and IL-2 amounts differed between the two treatment groups. Correlation analysis of of the indexes: in HT patients, the basal serum selenium concentration was positively correlated with TT₄ (r = 0.294, p < 0.05), significantly negatively correlated with TSH (r = -0.343, p < 0.01), and had no significant correlation with TT3 (p > 0.05).

Conclusions: These findings indicated that levothyroxine and selenium combination results in improved therapeutic effects than the levothyroxine monotherapy in preventing CLT progression.