Frequency of Insulin Resistance in People with Thyroid Dysfunction

Abstract

Background: Thyroid dysfunction is an endocrine disorder with a recognized
association with type 2 diabetes mellitus. Thyroid hormones have a remarkable effect
on glucose metabolism and can cause insulin resistance (IR). This study was aimed at
assessing the relationship between IR and thyroid dysfunction.
Methods: This case–control study was conducted at the endocrinology outpatient
clinics of Ibrahim Malik Hospital and Omdurman Military Hospital in Khartoum State,
Sudan between May 2018 and January 2019. Fasting blood glucose (FBG), fasting
insulin level, and thyroid function test (TFT) were measured for each candidate and IR
was estimated using the HOMA-IR equation.
Results: Thirty-one patients with thyroid dysfunction and fifty-seven control participants
were enrolled. The highest mean FBG was found among cases (105.3 ± 15.7 mg/dl)
compared to the controls (97 ± 12.1 mg/dl), but the difference was not statistically
significant (P-value = 0.598). The mean fasting insulin level was 9.22 ± 4 IU/ml in
the cases and 9.4 ± 4.2 IU/ml in controls, without a significant difference (P-value =
0.681). The highest HOMA-IR score was found among cases (2.4 ± 1.2). It was 2.4
± 1.3 in hyperthyroidism, 2.3 ± 1.1 in hypothyroidism, and 2.4 ± 1.2 in controls, and
the difference was insignificant (P-value = 0.859). IR was higher in the cases (58.1%)
compared to the controls (52.6%) but again not statistically significant (P-value = 0.396).
Among cases, IR was encountered in 61.9% and 50% of hyperthyroid and hypothyroid
patients, respectively.
Conclusion: Patients with thyroid dysfunction have some level of IR that was not
statistically significant when compared with controls.