Endocrine Abstracts

Context: Graves’ ophthalmopathy (GO) is a debilitating condition that affects 30% patients with Graves’ disease (GD). It is the most common extra-thyroidal manifestation of GD, but only 3-5% of GO cases are sight – threatening.

Objective: To compare the thyroid and lipid profile of GD patients who developed GO vs those without GO. The second objective is to analyze the prevalence of smoking status and insufficient 25 (OH) vitamin D levels.

Design: This is an observational, cross-sectional study in a tertiary endocrinology center.

Subjects and Methods: The study includes 151 GD adult patients treated with methimazole (MMI) alone (n=95) or MMI with levothyroxine (LT4) (n=56), with no history of radioactive iodine therapy or thyroidectomy. Pregnant women were excluded. Patients were divided into two subgroups according to the absence (GO-) or presence (GO+) of GO.

Results: The GO- subgroup included 92 (60.93%) patients aged 46.6±14.5 years and the GO+ subgroup included 59 (39.07%) patients aged 49.7±12.3 years. The proportion of smokers in GO+ subgroup was higher than in the GO- subgroup (P-value 0.004). The number of hypothyroid patients (fT4<8 pmol/l) was higher in the GO+ subgroup than in the GO- subgroup, 4/92 (4.32%) patients vs 8/59 (13.55%) patients (P-value 0.04). The mean dose of LT4 was higher in patients on block and replace therapy in the GO+ subgroup than in those in the GO- subgroup, 55.4±21.3 mg/day vs 42±17.9 mg/day (P-value 0.01). No differences in mean doses of MMI, treatment regimens and lipid profile were observed between the two subgroups. In patients with mild GO, triglyceride levels were lower than those with moderate-severe and severe GO (90.9±32.6 mg/dl vs 137.3±97 mg/dl, P-value 0.012). 25 (OH) vitamin D was measured in 60 patients in subgroup GO- and 42 patients in subgroup GO+. The mean level of 25 (OH) vitamin D was similar between the two subgroups: 26.17±9.74 ng/ml in subgroup GO- vs 23.3±11.8 ng/ml in subgroup GO+, P-value 0.2. When 25 (OH) vitamin D <20 ng/ml was selected, 16 (26.67%) of 60 patients in subgroup GO- and 21 (50%) of 42 patients in subgroup GO+ had insufficient vitamin D levels, P-value 0.01.

Limitation: The study did not include data on other risk factors for metabolic syndrome.

Conclusion: Identifying and manage GO’ risk factors such as smoking, hypothyroidism and high lipid profile may influence the course of GO. Vitamin D cut off below 20 ng/ml could be a risk factor for development of GO.