The addition of the PPAR-gamma agonist pioglitazone to levothyroxine decreased thyroid-stimulating hormone levels and improved insulin resistance in patients with hypothyroidism, according to data presented at EASD 2013.
Researchers conducted a crossover study involving eight men and 17 women with overt hypothyroidism and insulin resistance without diabetes. Patients received first-line treatment with levothyroxine only for 3 months before switching to a second-line approach with a combination of levothyroxine and pioglitazone (Actos, Takeda) for 3 more months.
TSH decreased after combination therapy with levothyroxine and pioglitazone vs. levothyroxine alone (1.57 mcIU/mL vs. 3.52 mcIU/mL; P<.001). Free triiodothyronine (3.17 pg/mL vs. 2.81 pg/mL; P<.001) and free thyroxine (1.65 ng/dL vs. 1.23 ng/dL; P<.001) also differed significantly between first- and second-line treatment approaches, according to study results.
The researchers observed a reduction in HbA1c after second-line as compared with first-line treatment. Significant declines in glucose, from 6.07 mmol/L to 4.91 mmol/L (P<.001), and insulin, from 15.94 mcIU/mL to 8.57 mcIU/mL (P<.001), between first- and second-line treatment approaches were also noted. Additionally, results demonstrated improvement in homeostasis model assessment of insulin resistance (HOMA-IR) index, from 4.29 to 1.87 (P<.001), after second-line vs. first-line treatment.
“To our knowledge, it was discovered for the first time that pioglitazone administration is characterized by elevation of thyroid hormone and by diminishing of thyroid-stimulating hormone. We also present novel data indicating pioglitazone as a drug with ability to decrease HbA1c, improve HOMA-IR index by lowering insulin and glucose without influence on HOMA-beta in hypothyroid patients. Therefore, our study suggests that PPAR-gamma receptors play a role in pathogenesis of hypothyroidism and PPAR-gamma agonist pioglitazone may have new indication to be used,” the researchers wrote.
For more information:
Moskva KA. Poster #976. Presented at: the 49th Annual Meeting of the European Association for the Study of Diabetes; Sept. 24-27, 2013; Barcelona, Spain.
Disclosure: Endocrine Today could not confirm researchers’ financial disclosures.