Can Treatment Prevent Thyroid Eye Disease?

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A large longitudinal study has identified two treatment approaches that appear to reduce the risk of thyroid-associated ophthalmopathy (TAO) in patients with Graves disease. Surgical thyroidectomy and regular use of anticholesterol statin drugs were individually associated with significant risk reduction.¹

Although these findings have not been confirmed, they could mark the beginning of a new clinical path, said senior author Raymond S. Douglas, MD, PhD, director of the Thyroid Eye Disease Center at the University of Michigan Kellogg Eye Center, in Ann Arbor.

“Thyroid-associated autoimmunity, which encompasses thyroid eye disease, is the most common autoimmune disease. In fact, it affects 1 in 100 people. But all the studies up until now have focused upon whether the treatment makes the eye disease better or worse,” Dr. Douglas said.

“Now, for the first time ever, we’re looking at interventions that actually can prevent the eye disease associated with Graves from happening—not just make it better, but prevent it.

“We currently have three ways to treat the underlying thyroid disease, and everyone believed they were about the same. But now this study suggests that, if you’re thinking about whether the patient will get the eye disease, the treatments really aren’t equivalent,” he said.

Study details. Dr. Douglas and colleagues examined nine years of data on all adults diagnosed with Graves disease within a large managed-care group. Of the 8,404 patients in the cohort, 740 (8.8 percent) eventually developed TAO.

Because Graves is an autoimmune disorder that causes inflammation, the researchers looked for evidence that certain common drugs with anti-inflammatory properties might interfere with the still-unknown mechanisms by which thyroid dysfunction affects orbital tissues, Dr. Douglas said. Statins and cyclooxygenase 2 (COX-2) inhibitors were among the drugs investigated.

The following are key findings from the study:

• After the researchers controlled for confounding variables, the hazard ratio (HR) for TAO was 40 percent lower (adjusted HR, 0.60; 95% confidence interval [CI], 0.37-0.93) in Graves patients who took statins for 60 or more days per year compared with those who did not (p < .05). Other cholesterol-lowering medications had no effect.
• Patients who had thyroidectomy had a 74 percent reduced risk of progressing to TAO compared with those treated with radioactive iodine (adjusted HR, 0.26; 95% CI, 0.12-0.51).
• Radioiodine treatment and antithyroid medication, alone or in combination, did not reduce the TAO risk.
• COX-2 inhibitors had no effect on TAO risk.

Potential applications. Typically, there is a natural point in the course of Graves disease at which preventive treatment might be initiated, Dr. Douglas noted.

“What we know now is that patients usually get the thyroid problem, and then we usually have a window of about six months until they get the eye disease,” he said. “Our study should prompt ophthalmologists to make sure that the patient with Graves disease gets a thoughtful opinion on how to handle their thyroid issue, at an early stage.

“About 20 percent of the time the disease presents with eye issues first,” Dr. Douglas added. “So the ophthalmologist is a very important member of that early-phase team, when all these treatment decisions are being made.”

—Linda Roach

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1 Stein JD et al. JAMA Ophthalmol. Published online Dec. 11, 2014.

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Dr. Douglas reports no related financial interests.

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