Treatment outcome and predictors of better response to thyroxin in hypothyroid patients with sleep apnea syndrome in Zagazig University hospital

Abstract Background Many studies suggest that sleep-disordered breathing (SDB) is common among patients with hypothyroidism. Obstructive sleep apnea syndrome (OSAS) is characterized by complete cessation of inspiratory flow (apnea) or upper airway airflow limitation (hypopnea) with increased respiratory muscle activity, which is repeatedly observed during sleep. Hypothyroidism and OSA have overlapping clinical presentations. Excessive daytime somnolence, apathy and lethargy are known to occur in patients with hypothyroidism. Aim This study was designed to detect predictors for better response to thyroxin therapy in hypothyroid patients presented with OSAS and to pick up features of other hypothyroid patients who still presented with obstructive sleep apnea and remain in need of CPAP beside thyroxin therapy, after euthyroid state had been reached. Settings and design This randomized controlled clinical trial study was conducted in Chest and Internal Medicine departments, Zagazig University Hospitals. Patients and methods A total of 130 patients, 65 with hypothyroidism had manifestations of OSA confirmed by sleep study (1 st polysomnography) (group I) and 65 euthyroid patients with manifestations of OSA as a control subjects, were treated by CPAP (group II). After reaching euthyroid state, another sleep study (2 nd polysomnography) was done, then patients were subdivided into : 40 patients whom polysomnographic study improved markedly after thyroxin therapy and advised to continue on thyroxin replacement (IA subgroup) and 25 patients showed no significant improvement and planned for CPAP therapy along with thyroid therapy (IB subgroup). Results Neck circumference, BMI and Epworth score were statistically significantly higher in hypothyroid group (p ≤ 0.002, Conclusions Some hypothyroidism patients with OSA will improve on hormonal therapy alone but other will continue to need CPAP. Neck circumference, free T4 and TSH levels may help us in predicting the response of these patients.