Predictors of Thyroid Dysfunction in Patients with Type 2 Diabetes Mellitus: A Case-Control Study

Abstract

Aim: To determine the predictors and prevalence of thyroid disorders as a result of diabetes mellitus.

Study Design: Case-control study

Place and duration: This study conducted at department of Medicine, Bilawal Medical College for boys LUMHS Jamshoro Pakistan from July 2019 to July 2020

Methodology: In this study, 1000 patients with type 2 diabetes were enrolled. They all underwent thyroid investigation including thyroid stimulating hormone, free triiodothyronine and free thyroxine. In addition to these, the glycated hemoglobin of all the patients was also assessed. Total 390 non diabetic patients of same age group were allocated in the control group. The investigations of control and case groups were compared.

Results: The total number of participants in the study was 1390. 47.98% of the subjects were female and 52.02% were male. The mean age of the participants was 60.2 years with a standard deviation of 13.1. Out of all the participants having type 2 diabetes mellitus, 208 participants were known cases of thyroid disorder (14.96%), whereas 180 new cases of thyroid disorder were diagnosed (12.94%). Therefore, the prevalence of thyroid disorder was 27.9% in diabetic patients. This percentage is much higher than the control group i.e. 14.2% (p<0.001). The most common type of thyroid disorder found in diabetic patients was subclinical hypothyroidism. After analysis of the data, it was found that the risk factors for thyroid disorders for the diabetic patients were age equal to or more than 50 years, female gender, glycated hemoglobin more than 7% and goiter. Duration of diabetes and complications seem to have no role in thyroid disorder in patients with type 2 diabetes mellitus.

Conclusion: There is a strong association between type 2 diabetes mellitus and thyroid disorders. It is advised to diabetic patients to get screened for thyroid dysfunction in routine. The risk factors in this context are female gender, old age, poor glycemic control and goiter. Hence, the proper management of the glycemic index can potentially lower the risk of thyroid dysfunction.