Hyperthyroid patients without Graves' orbitopathy are not at increased risk of developing glaucoma: a nationwide Danish register-based case-control study.

Abstract

Graves' disease (GD) and toxic nodular goiter (TNG) are associated with various comorbidities. However, it is unclarified whether TNG and GD without orbitopathy are associated with glaucoma. This was a case-control study using record-linkage data from nationwide Danish health registers. 28,461 patients with GD and 17,283 with TNG were included. Each case was age and sex matched with four non-hyperthyroid controls and followed over a mean period of 8 years. Data on glaucoma was obtained by record linkage within the National Danish Patient Register and/or the Danish National Prescription Registry. Logistic and Cox regression models were used to assess the risk of glaucoma before and after the diagnosis of GD and TNG. Compared to controls, there was a significantly increased frequency of glaucoma in patients with GD (4.6 vs. 4.2%, P = 0.006) and in patients with TNG (6.2 vs. 5.7%, P = 0.003). Prior to the diagnosis of hyperthyroidism, the odds ratio (OR) for glaucoma was non-significant in GD (1.09, 95% CI: 1.00-1.18) but slightly increased in TNG (1.13, 95% CI: 1.02-1.24). However, in TNG the OR attenuated completely when only including patients without co-morbidity in the analysis (1.03, 95% CI: 0.93-1.14). After adjustment for pre-existing co-morbidity, the hazard ratio (HR) for glaucoma following GD and TNG was not significantly increased (HR 1.08, 95% CI: 0.98-1.18 and HR 1.10, 95% CI: 0.99-1.21, respectively). Neither prior to nor following the diagnosis of GD and TNG had any significant association with glaucoma.