BMC Endocrine Disorders (Jul 2023)

Thyroid function, glycemic control, and diabetic nephropathy in patients with type 2 diabetes over 24 months: prospective observational study

  • Hiroshi Iwakura,
  • Tomoyuki Takagi,
  • Hidefumi Inaba,
  • Asako Doi,
  • Yoko Ueda,
  • Shinsuke Uraki,
  • Ken Takeshima,
  • Yasushi Furukawa,
  • Tatsuya Ishibashi,
  • Shuhei Morita,
  • Shohei Matsuno,
  • Masahiro Nishi,
  • Hiroto Furuta,
  • Taka-aki Matsuoka,
  • Takashi Akamizu

DOI
https://doi.org/10.1186/s12902-023-01393-4
Journal volume & issue
Vol. 23, no. 1
pp. 1 – 8

Abstract

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Abstract Background The higher prevalence of thyroid dysfunction in type 1 diabetes patients has been well established, whereas it is a matter of debate whether that is also observed in type 2 diabetes patients. This study was conducted to reveal whether higher prevalence of thyroid dysfunction is observed in patients with type 2 diabetes. Methods We examined thyroid functions and thyroid autoantibodies in 200 patients with type 2 diabetes and 225 controls, with 24 months follow up for those with type 2 diabetes. Results Serum free triiodothyronine (fT3) levels and fT3/free thyroxine (fT4) ratio were significantly lower, while fT4 levels were significantly higher in patients with type 2 diabetes. The number of patients with thyroid dysfunction or patients positive for thyroid autoantibodies were not different between the two groups. The fT3/fT4 ratio was positively and negatively correlated with serum c-peptide and HbA1c levels, respectively, suggesting that the difference can be attributable to insulin resistance and diabetic control. In the follow-up observation, we found no significant correlation between basal thyrotropin (TSH), fT3, fT4 or fT3/fT4 ratio with the amounts of changes of HbA1c levels at 12 or 24 months after the basal measurements. There was a negative relationship between TSH levels and eGFR at baseline measurements, but TSH levels did not seem to predict future decline of eGFR levels. No relationship was observed between urine albumin/ g‧cre levels and thyroid function. Conclusion Thyroid dysfunction and thyroid autoantibodies were not different in prevalence between patients with type 2 diabetes and controls, although in patients with type 2 diabetes, the fT3/fT4 ratio was decreased. Basal thyroid function did not predict future diabetes control or renal function within 24 months of follow-up.

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