Hypo vs. hyperthyroid eye disease: is there any difference?

BACKGROUND: Thyroid-eye disease (TED) is the most common extra-thyroidal presentation of graves’ disease. We performed this study to compare clinical characteristics of TED in hypothyroid vs. hyperthyroid patients. METHODS: This was a retrospective analytical cross-sectional study in which we compared demographics, severity (EUGOGO classification) and activity (clinical activity score) of TED, thyroid disease duration, TED duration and clinical signs between hypothyroid eye disease (Ho-TED) and hyperthyroid eye disease (Hr-TED). To minimize the effect of selection bias and potential confounders, 1:1 propensity score matching (PSM) was also performed. RESULTS: Three hundred and seventy-four patients (341 Hr-TED and 33 Ho-TED) with a female to male ratio of 1.4:1 were identified in our study. Female to male ratio was 1.3:1 in hyperthyroid and 4.5:1 in hypothyroid group (P = 0.005). The duration of thyroid disease was longer in Ho-TED (P = 0.002) while the duration of eye disease was not significantly different between the Hr-TED (mean = 24.33 ± 41.69, median = 8) and Ho-TED (mean = 19.06 ± 33.60, median = 12) (P = 0.923). Most of the patients in hypothyroid group developed eye involvement after thyroid disease (80.0% in hypo vs. 48.1% in hyper, P = 0.003). Severity (P = 0.13) and activity (P = 0.11) was not different between Hr-TED and Ho-TED patients. After PSM analysis, no clinical characteristics were significantly different between the two groups (P > 0.05). CONCLUSION: The results of our study showed several differences between the Hr/Ho TED patients including sex, duration of thyroid disease and pattern of eye involvement. After matching the two groups with statistical methods, no clinical characteristics were different between Hr-TED and Ho-TED patients.