Prevalence and Pattern of Thyroid Dysfunction in Patients with Type 2 Diabetes Mellitus: A Prospective Observational Study.

Abstract

Background:

Thyroid dysfunction is a common endocrine disorder frequently associated with Type 2 Diabetes Mellitus (T2DM) and may adversely affect glycemic control and diabetic complications.

Objectives:

To determine the prevalence and pattern of thyroid dysfunction among patients with T2DM and evaluate its association with demographic and clinical variables.

Methods:

This prospective observational study included 250 patients with T2DM attending the Department of General Medicine, Madhubani Medical College and Hospital, Bihar, from 1 April 2025 to 31 January 2026. Demographic and clinical data were collected. Thyroid profile, including serum Thyroid Stimulating Hormone (TSH), free T3, and free T4, was assessed. Statistical analysis was performed using the Chi-square test and Student's t-test, with p<0.05 considered statistically significant.

Results:

Of the 250 participants, 141 (56.4%) were males, and 109 (43.6%) were females, with a mean age of 54.8 ± 10.6 years. Thyroid dysfunction was identified in 72 patients (28.8%). Subclinical hypothyroidism was the most common abnormality (16.0%), followed by overt hypothyroidism (8.0%), subclinical hyperthyroidism (3.2%), and overt hyperthyroidism (1.6%). Thyroid dysfunction was significantly more common among females than males (37.0% vs. 22.1%; p=0.011) and among patients with HbA1c ≥8% compared with those with HbA1c <8% (35.7% vs. 19.8%; p=0.008).

Conclusion:

Thyroid dysfunction is highly prevalent among patients with T2DM, particularly among females and those with poor glycemic control.

Recommendation:

Routine thyroid screening should be considered in patients with T2DM for early diagnosis and timely management.