High Serum Cholesterol Is a Novel Risk Factor for Graves' Orbitopathy: Results of a Cross-Sectional Study.

BACKGROUND: Limited data suggest that treatment with statins is associated with a reduced risk of Graves' orbitopathy (GO) in patients with Graves' disease (GD), attributed to the anti-inflammatory rather than to the hypolipemic effects of these medications. The aim of the present study was to investigate whether there is an association between high cholesterol and GO. The primary outcome was the relation between GO and low-density lipoprotein (LDL)-cholesterol. The secondary outcomes were the relation between severity or activity (the clinical activity score [CAS]) of GO and LDL-cholesterol.

METHODS: A cross-sectional investigation was conducted in consecutive patients with GD who came under the authors' observation to undergo radioiodine treatment, a stratification aimed at forming two distinct groups of patients under the same conditions. A total of 250 patients were enrolled, 133 with and 117 without GO. Ophthalmological assessments and serum lipids measurements were performed.

RESULTS: In multivariate analyses with correction for the duration of hyperthyroidism, a variable that differed between patients with respect to the presence or absence of GO, a correlation between the presence of GO and both total (p = 0.01) and LDL-cholesterol (p = 0.02) was observed. In patients with hyperthyroidism lasting <44 months, total and LDL-cholesterol were higher (p = 0.01 and p = 0.008, respectively) among GO patients. In this subgroup, based on the presence/absence of GO, cutoff values were established for total (191 mg/dL) and LDL-cholesterol (118.4 mg/dL), above which an increased risk of GO was observed (total cholesterol relative risk: 1.47; p = 0.03; LDL-cholesterol relative risk: 1.28; p = 0.03). GO severity and CAS did not correlate with serum lipids. However, CAS was found to be higher (p = 0.02) in patients with high total cholesterol. When the analysis was restricted to untreated GO patients, a correlation was found between CAS and both total (p = 0.04) and LDL-cholesterol (p = 0.03), after adjustment for GO duration.

CONCLUSIONS: In patients with a short duration of hyperthyroidism, total and LDL-cholesterol correlate with the presence of GO, suggesting a role of cholesterol in the development of GO. Depending on GO duration, total and LDL-cholesterol correlate with GO activity, suggesting a role of cholesterol in the clinical expression of GO.