Prevalence and predictors of thyroid dysfunction amongst patients with Type 2 diabetes mellitus in Pakistan

Diabetes and thyroid disorders are the two most common disorders amongst endocrine diseases. Uncontrolled diabetes mellitus (DM) may disturb thyroid metabolism by disturbing the levels of thyroid hormones in the plasma. This study was undertaken to determine the prevalence and thyroid dysfunction in type 2 diabetic population presenting in a public sector tertiary care teaching hospital.

This descriptive cross-sectional study was conducted in Civil Hospital Karachi (CHK) in the department of medicine from October 01, 2018, to March 31, 2019. The study population consisted of 317 patients diagnosed with DM type 2 based on American Diabetes Association (ADA) criteria. Patients with fasting blood sugar ≥ 126 mg/dL, or HbA1c >6.5 (%), and 2 h postprandial blood glucose levels >200 mg/dL were included. After a minimum of 8 h of fasting, plasma samples of patients were collected and sent for fasting blood glucose, HbA1c, FT3, FT4, and thyroid-stimulating hormone (TSH). Descriptive statistics were calculated. Post-stratification Chi-squared test was applied, and a P value of ≤ 0.05 was considered significant.

Among all enrolled DM type 2 patients, 207 (65.3%) were male with a mean age of 46.54 ± 8.72 years. Mean fasting blood sugar (FBS), random blood sugar (RBS), and HbA1c were 212.76 ± 26.91 (mg/dL), 328.89 ± 52.89 (mg/dL), and 9.43 ± 2.47 (%), respectively. The mean duration of DM was 7.81 ± 3.15 years. Mean FT3, FT4, and TSH were 113.13 ± 44.40 (ng/dL), 7.63 ± 3.11 (mg/dL) and 2.64 ± 2.57 (mIU/mL), respectively. In the present study, 55 (17.4%) patients had subclinical hypothyroidism, 27 (8.5%) had hypothyroidism, 19 (6.0%) had hyperthyroidism, and 16 (5.0%) had subclinical hyperthyroidism. Significant association of thyroid dysfunction was established with age group, female gender, and family history of thyroid dysfunction (P =< 0.001).

The prevalence of thyroid dysfunction is higher among patients with type 2 diabetes mellitus (T2DM), in which hypothyroidism was the most common dysfunction with more prevalence among female patients.