Risk factors for developing thyroid-associated ophthalmopathy among individuals with Graves disease

Abstract

Importance: Thyroid-associated ophthalmopathy (TAO) is a common and debilitating manifestation of Graves disease (GD). Presently little is known about factors that may increase the risk of developing TAO among patients with GD.

Objective: To identify risk factors associated with the development of TAO among individuals with newly diagnosed GD.

Design, setting, and participants: In this longitudinal cohort study, all beneficiaries 18 years of age or older with newly diagnosed GD who were continuously enrolled in a large nationwide US managed care network and who visited an eye care professional 1 or more times from 2001 to 2009 were identified. International Classification of Diseases, Ninth Revision, Clinical Modification billing codes were used to identify those who developed manifestations of TAO. Multivariable Cox regression was used to determine the hazard of developing TAO among persons with newly diagnosed GD, with adjustment for sociodemographic factors, systemic medical conditions, thyrotropin levels, and medical and surgical interventions for management of hyperthyroidism.

Main outcomes and measures: Manifestations of TAO measured by hazard ratios (HRs) with 95% CIs.

Results: Of 8404 patients with GD who met the inclusion criteria, 740 (8.8%) developed TAO (mean follow-up, 374 days since initial GD diagnosis). After adjustment for potential confounders, surgical thyroidectomy, alone or in combination with medical therapy, was associated with a 74% decreased hazard for TAO (adjusted HR, 0.26 [95% CI, 0.12-0.51]) compared with radioactive iodine therapy alone. Statin use (for ≥60 days in the past year vs <60 days or nonuse) was associated with a 40% decreased hazard (adjusted HR, 0.60 [CI, 0.37-0.93]). No significant association was found for the use of nonstatin cholesterol-lowering medications or cyclooxygenase 2 inhibitors and the development of TAO.

Conclusions and relevance: If prospective studies can confirm our finding that a thyroidectomy and statin use are associated with substantially reduced hazards for TAO among patients with GD, preventive measures for this burdensome manifestation of GD may become a reality.

Figure 1

Selection of Beneficiaries for Analysis *Incident = the diagnosis or prescription was not present during the beneficiary’s first year of enrollment in the managed care plan. GD= Graves Disease; TSH = thyroid stimulating hormone