Is Subclinical Hyperthyroidism Common in Patients with Type 2 Diabetes?

The word hyperthyroidism on a tablet with a stethoscopeType 2 diabetes and subclinical hyperthyroidism have been linked to an increased risk of both cardiovascular disease and mortality. But how common is subclinical hyperthyroidism in patients who have type 2 diabetes?

Researchers evaluated the prevalence of patients with type 2 diabetes who were recently diagnosed with subclinical hyperthyroidism. They also assessed the link between diabetes-related characteristics and the presence of subclinical hyperthyroidism in these patients.

Their study was published online in February 2012 in the article “Subclinical hyperthyroidism in patients with type 2 diabetes.” The article will appear in an edition of the journal Endocrine.

Researchers divided study participants into 2 groups—a case group and a control group.

The case group included a total of 933 people with diabetes who did not have a history of thyroid disease. Of these participants, 54.6% were males and 45.4% females. The mean age of these patients was 66.3 years old. On average, these patients had diabetes for 10 years.

The control group included 911 patients who did not have diabetes and who did not have a known thyroid condition.

The research team measured serum concentrations of thyrotropin for all participants.

They found that 4.3% of female patients with diabetes and 3.5% of male patients with diabetes also had subclinical hyperthyroidism.

In addition, they found that the relative risk was significant only for the women in the study (odds ratio: 3.69; 95% confidence interval [CI]: 1.56 to 8.71).

Compared with the patients with diabetes who did not have thyroid hyperfunction, patients with subclinical hyperthyroidism:

  • were older
  • had a longer duration of diabetes
  • showed lower fasting blood glucose levels
  • had a greater proportion of goiter and diet therapy
  • had a lower proportion of treatment that used oral agents

The research team also used logistic regression analysis. Using this analysis, they found that both being older and having a goiter are significantly and independently linked to subclinical hyperthyroidism in patients who have diabetes. They concluded that the risk for subclinical hyperthyroidism is increased in women who have type 2 diabetes.