Prevalence of hypothyroidism in newly diagnosed patients with obstructive sleep apnea syndrome: a prospective cross-sectional study

Abstract

Introduction:
One of the most common presentations of OSAS is daytime sleepiness, which is also seen in patients with hypothyroidism. We hypothesized that hypothyroidism is one of contributing factors in the development of OSAS; thus, adequate management of hypothyroidism can simply help to alleviate OSAS symptoms.


Aim of the Study:
The aim of this study was to evaluate the prevalence of hypothyroidism in OSAS patients in our locality and to compare respiratory polysomnographic parameters of OSAS patients with hypothyroidism versus those without hypothyroidism.


Patients and Methods:
In a descriptive prospective cross-sectional study, our patients attending Sleep Disordered Breathing Clinic at Sleep Disordered Breathing Unit, Chest Medicine Department, Mansoura University Hospital. All patients were subjected to full history taking with stress on sleep questionnaires, pulmonary complaints, physical examination, anthropometric measures, diagnostic PSG, laboratory evaluation (serum TSH and free T4 levels), and chest radiology and echocardiography.


Results:
There were two groups of OSAS participants (hypothyroid and euthyroid). Hypothyroidism was evident in 12% of patients;they were classified according to AHI, 13, 15, and 60 of Euthyroid patients had mild, moderate, and severe OSAS, respectively. hypothyroid patients, 2 mild OSAS, 1 moderate OSAS and 9 severe OSAS. Epworth sleepiness scale scores were significantly higher in the hypothyroid group with a mean score of 18 ± 4.8 vs 12.47 ± 6 in the euthyroid group (P = 0.003). Different PSG parameters showed no difference between the two groups. AHI, serum TSH level, and T4 levels were positively correlated but with insignificant P values.


Conclusion:
Hypothyroidism is thought to be one of the key players in the development of sleep-breathing disorders. It was evident in 12% of OSAS patients; however, the a proven insignificant difference in PSG parameters in OSAS with hypothyroidism versus euthyroid group, except for affection of daytime sleepiness.