Predictive factors of development of dysthyroid optic neuropathy among individuals with thyroid-eye disease

Purpose: Dysthyroid optic neuropathy (DON) is a severe visual loss condition in thyroid eye disease (TED). This study aimed to identify factors affecting moderate-to-severe TED or DON in Thai populations.Methods: We retrospectively reviewed the records of 230 TED patients at Rajavithi Hospital between January 1, 2017, and October 31, 2022.Results: Mild, moderate-to-severe TED, and DON were found in 60.43%, 22.61%, and 16.96% of participants, respectively. Female predominance was noted in all groups. The proportion of older age, hyperthyroidism, current smokers, and type 2 diabetes mellitus (T2DM) participants were significantly higher in the DON group. Multivariable logistic-regression analysis revealed that hyperthyroidism and current smoking significantly increased the risk of developing moderate-to-severe TED (OR = 3.001, p = 0.010, and OR = 4.153, p = 0.015, respectively). Exophthalmos was the strongest predictor (OR = 6.834, p < 0.001). Regarding DON risk factors, older age (=55 years) had OR = 3.206 (p = 0.003), hyperthyroidism had OR = 3.228 (p = 0.005), and being a current smoker had OR = 3.781 (p = 0.011). T2DM posed the greatest risk of DON development (OR = 4.111, p = 0.004).Conclusions: Hyperthyroidism and current smoking are significant risk factors for moderate-to-severe TED and DON. TED patients with diabetes mellitus or older age should be closely monitored and informed about their risk of developing DON.