Adults with thyroid eye disease and diabetes have a higher prevalence of diplopia, strabismus and sight-threatening disease compared with those without diabetes, according to study findings published in Endocrine Practice.

Lissa Padnick-Silver

“This study provides further evidence that thyroid eye disease is more severe in patients with diabetes. More frequent severity manifested in higher rates of optic neuropathy, perhaps because of greater optic nerve vulnerability stemming from diabetes-related vasculopathies,” Lissa Padnick-Silver, PhD, senior manager of medical affairs, publications and data management for Horizon Therapeutics, told Healio. “Further, thyroid eye disease patients with diabetes were noted to have less proptosis and more extraocular muscle involvement than patients without diabetes. To the best of our knowledge, this finding has not been previously reported and further study is warranted.”

Researchers analyzed data from the Symphony insurance claims database on medical claims for 51,220 adults with Graves’ disease or thyroid eye disease from 2010 to 2015. Patients with a diagnosis of Graves’ disease or thyroid eye disease with data in Symphony for at least 2 years after diagnosis were included. Diabetes status was obtained from the database. Sight-threatening thyroid eye disease included those with optic neuropathy or exposure keratopathy.

Of the study cohort, 5.1% had type 1 diabetes, and 25.1% had type 2 diabetes. Adults with type 1 diabetes and type 2 diabetes had a higher prevalence of strabismus (type 1 diabetes, 25.4% vs. type 2 diabetes, 22.6% vs. no diabetes, 19.9%; P < .001) and diplopia (38.6% vs. 37.9% vs. 29.9%, respectively; P < .001) and a lower prevalence of proptosis (42.3% vs. 46.3% vs. 58.5%, respectively; P < .001) compared with those without diabetes.

Sight-threatening thyroid eye disease was reported in 11.7% of the study cohort. Patients with type 1 diabetes and type 2 diabetes had higher prevalence of sight-threatening thyroid eye disease compared with those without diabetes (13.3% vs. 12.8% vs. 11.2%, respectively; P < .001). In all diabetes subgroups, women were more likely to have sight-threatening thyroid eye disease than men.

Of the study cohort, 13.5% had at least one thyroid eye disease-related surgery. Patients without diabetes had a higher surgical rate compared with those with type 2 diabetes (14% vs. 12.3%; P < .001). Patients with type 2 diabetes had a higher rate of full-thickness keratoplasty compared with those without diabetes (1.9% vs. 0.7%; P < .001), whereas eyelid surgery rates were higher among those without diabetes compared with the type 2 diabetes group (58.8% vs. 54.9%; P = .007). Neither group had any significantly different surgery rates compared with those with type 1 diabetes.

“Knowing that thyroid eye disease patients with diabetes may be at an increased risk for optic nerve injury is important and may warrant closer monitoring and earlier referral to a thyroid eye disease specialist,” Padnick-Silver said. “Further, the finding that proptosis may be less common and muscle involvement more common indicates that patients with diabetes and Graves’ disease may require special attention and monitoring for visual and ocular muscle abnormalities characteristic of thyroid eye disease, particularly eye misalignment and double vision.”

Padnick-Silver said the next step in research could be a retrospective chart review with a larger population of people with thyroid eye disease both with and without diabetes.

“This would allow us to have more clinical details on these patients to better understand important factors about both the impact and interplay of diabetes and thyroid eye disease,” Padnick-Silver said.