MON-595 Clinical Characteristics of Obstructive Sleep Apnea in Grave's Disease with Normal Thyroid Function

Background: The prevalence of obstructive sleep apnea (OSA) is increasing and is related to obesity, hypertension and cardiovascular events. Hormonal abnormalities due to hypothyroidism and large goiter can cause OSA. However, the association between OSA and Graves' disease (GD) is not studied well. GD is a major cause of thyrotoxicosis associated with various symptoms like weight loss, palpitations, and hyperhidrosis. After the treatment for normalizing thyroid function, patients sometimes experience metabolic abnormality, like weight gain and dyslipidemia. The objective of our study is to explore clinical characteristics of OSA coexisting with GD. Patients and Method: Patients diagnosed as GD with normalized thyroid function by anti-thyroid medications, radioiodine therapy, and surgery were enrolled from September 1st, 2017 to September 30th, 2018 in accordance with written informed consent. Normal thyroid function was defined by serum Free T4 level ranging from 0.8 ng/dL to 1.7 ng/dL. Patients were undergone polysomnography, and OSA was defined by apnea-hypopnea index greater than 5 times/hour. Patients were divided into 2 groups according to the existence of OSA. Patient’s profile including age, physical signs, disease duration from diagnosis to entry, thyroid function test, and data from polysomnography were obtained and analyzed between the two groups. Results: Sixteen patients aged 46.4 ± 13.0 years (2 male,14 female) were included in this study. Eight of 16 patients (50 %) were categorized into OSA positive group (OSA+). There were no significant differences between OSA+ and OSA negative group (OSA-) in gender, body mass index (BMI), disease duration, and thyroid function test, though BMI tended to be higher in OSA+ (data not shown). Mean Age of OSA+ was significantly higher than that of OSA- (53.6 ± 12.0 vs 39.3 ± 10.0 years, p < 0.05). In addition, systolic blood pressure (136.8 ± 10.0 vs 117.9 ± 11.8 mmHg, p <0.05) and diastolic blood pressure (79.4 ± 5.2 vs 70.3 ± 6.5 mmHg, p <0.05) of OSA+ were significantly higher than those of OSA-. Conclusions: Our findings suggested that the prevalence of OSA in GD after normalizing thyroid function might be higher than that of general populations in Japan. Furthermore, OSA was experienced in GD with higher age and higher blood pressure, even though their thyroid function was normalized. Persistent hypertension after normalizing thyroid function may be associated with OSA especially in elderly patients with GD.