Insulin Sensitivity and Beta-Cell Function in Graves' Disease and Their Changes with the Carbimazole-Induced Euthyroid State.
Eur Thyroid J 2019;
8:59-63. [PMID:
31192143 PMCID:
PMC6514524 DOI:
10.1159/000496924]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 01/14/2019] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND AND OBJECTIVE
Thyroid hormones play an important role in intermediate metabolism, and abnormal glucose tolerance is often observed in patients with hyperthyroidism. Several pathogenic mechanisms have been proposed as contributors. However, there is no conclusive evidence in the existing literature regarding the predominant underlying pathophysiology. Our objective was to determine the changes in insulin resistance parameters and beta-cell function in patients with Graves' disease following restoration of a euthyroid state.
METHODOLOGY
This was an observational study with a before-after study design. Forty-five treatment-naïve adults with Graves' diseases were included and 36 completed the study. An oral glucose tolerance test was performed at baseline and after 3 months of achieving a stable euthyroid state to assess glucose tolerance, insulin sensitivity, and beta-cell function. All patients were treated with antithyroid medication. The outcome measures studied were the Homeostasis Model Assessment-2 Insulin Resistance (HOMA2-IR), Matsuda index, and Insulin Secretion-Sensitivity Index (ISSI)-2.
RESULTS
Two-thirds of the patients had abnormal glucose tolerance at baseline. Among those with abnormal glucose tolerance at baseline, 34.7% had persistent abnormality during follow-up. During follow-up, no significant change was noted in the indices of insulin resistance. Patients with abnormal glucose tolerance had a significantly lower ISSI-2 index at baseline and it improved after achieving a euthyroid state.
CONCLUSIONS
Abnormal glucose tolerance is a significant metabolic consequence in patients with Graves' disease. Decreased beta-cell function was observed among those with abnormal glucose tolerance and it improved during follow-up. In a proportion of patients, abnormal glucose tolerance persisted after 3 months, emphasizing the need for continued follow-up.
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