Prevalence of Thyroid Dysfunction in Patients with Type 2 Diabetes

Aim: Assess the prevalence of thyroid dysfunction in patients with type 2 diabetes (T2D) in Segovia (Spain). Methods: A screening program for thyroid dysfunction including all patients with T2D attending the diabetes clinic at the Hospital General de Segovia was performed from 2003 to 2005. Results: 318 patients (191 women, aged 29-89yr, median duration of diabetes 8 yr) attended the diabetes clinic. The number of patients with thyroid dysfunction and their respective prevalences were: overt hyperthyroidism, 11 (3.5%); subclinical hyperthyroidism, 10 (3.1%); overt hypothyroidism, 48 (15.1%), and subclinical hypothyroidism, 34 patients (10.7%). The screening program detected the following cases of newly diagnosed thyroid dysfunction: subclinical hyperthyroidism, 5 (1.6%); overt hypothyroidism, 6 (1.9%), and subclinical hypothyroidism, 20 patients (6.3%). Therefore, total thyroid dysfunction was present in 32.4% (95% CI, 27.3-37.5%), and newly diagnosed thyroid dysfunction was present 9.7% (95% CI, 6.5-13.0%) of the patients. Logistic regression analysis showed that there were no significant relationships between the presence of thyroid dysfunction and duration of diabetes, hemoglobin A1c levels, and the presence of diabetic complications. Conclusion: This screening program detected new cases of thyroid dysfunction in similar to 10% of diabetic subjects. However, we could not identify any diabetes-related clinical parameter with predictive value on the presence of thyroid dysfunction.