Association between thyroid abnormalities & glycemic control among adults with type 1 Diabetes Mellitus: Cross-sectional study in Saudi Arabia.

Abstract

Background: The type 1 diabetic population has an increased incidence of thyroid dysfunction, accounting for approximately 17-30%. Thyroid dysfunction may interfere with insulin sensitivity and insulin requirements in individuals who have type 1 diabetes. This study aimed to find an association between thyroid function and poor glycemic control among adults with type 1 diabetes mellitus using TSH and HbgA1C, respectively.

Methods: A cross-sectional study was conducted in King Abdulaziz Medical City, Riyadh – Kingdom of Saudi Arabia (a tertiary hospital). Our subjects were adults with type 1 diabetes mellitus who had their TSH levels tested, between 2015 to 2019. Patients were categorized based on their TSH level as either hypothyroid, hyperthyroid, or normothyroid. The following variables were measured: patient’s demographics, Thyroid-stimulating hormone level, the presence of anemia, WBCs, LDL level, and history of diabetic ketoacidosis.

Results: There were a total of 1425 adult patients with T1DM between 2015 and 2019, only 282 patients fulfilled our inclusion criteria. 36.2% were males (N=102) and 63.8% were females (N=180). The patients’ mean age was 27.03 years with an average BMI of 25.62 kg/m2. 18.4% were hypothyroid and 9.9% were hyperthyroid. Our subjects had a mean HbA1c of 8.76%. hyperthyroid patients had higher HbA1c levels with a mean of 8.907 while hypothyroid patients had a mean of 8.11%. Also, we have found that patients with hyponatremia tend to have poor glycemic control in comparison to hypernatremia and normal serum sodium. We found that age, TSH, having a history of diabetic ketoacidosis and serum sodium to be significantly associated with HbA1c with P-values of 0.016, 0.012, 0.005 and <0.001 respectively.

Conclusion: Thyroid dysfunction was observed in a high proportion of our patients. We have found a clear association between thyroid function and glycemic control among adults with type 1 diabetes mellitus. Glycemic control was better among hypothyroid patients compared to hyperthyroid and normothyroid patients. Also, glycemic control is poor in hyponatremia in comparison to hypernatremia and normal serum sodium patients. HbA1C was significantly associated with age, TSH, serum sodium, and having a history of diabetic ketoacidosis but not with gender, body mass index and LDL level.