Polysomnographic evaluation of sleep quality and quantitative variables in patients of hypothyroidism

Poor sleep quality is observed in patients of hypothyroidism. The patient complains of sleeplessness, excessive day-time sleepiness, snoring, arousals and breathlessness. The decrease in quantity and quality of sleep occurs in various degrees of severity in patients of hypothyroidism.

To evaluate sleep quality and quantitative variables in patients of clinical and subclinical hypothyroidism.

This community-based cross-sectional study was conducted in 30 diagnosed cases of untreated subclinical and clinical hypothyroidism in the ages between 30 and 50; the serum levels of TSH, tT3, tT4 were evaluated by Chemiluminescent Immunoassay (CLIA) method. Participants were asked to fill an Epworth Sleepiness Scale (ESS) questionnaire to assess the quality of sleep. The Polysomnography was conducted using a "Polysomnography System for Sleep Studies (Make SOMNO medics, Germany)." The variables evaluated from PSG report included total sleep time, sleep efficiency, sleep stage percentage, sleep onset latency, arousal index, apnea-hypopnea index (AHI), oxygen desaturation index, and snoring scores. The data were analyzed using statistical software SPSS-23.0. The comparison among the group was carried using unpaired "t" test. The P values <0.05 were considered statistically significant.

The data analysis showed decreased sleep efficiency (68.93 ± 13.96) and decreased sleep onset latency (6.32 ± 8.87), increased N1 duration- 21.01 ± 16.69 minutes (normal: 5-10%), decreased N3- 8.56 ± 11.21 minutes (normal: 15-25%), REM duration- 12.46 ± 10.07 minutes (normal: 20-25%), and Epworth Sleepiness Scale values were found to be significantly higher in patients of clinical hypothyroidism as compared to patients of subclinical hypothyroidism. AHI (18.74 ± 13.2) (normal: <5) and ODI values (14.16 ± 176.6) are increased in patients of hypothyroidism. AHI was found to be significantly higher in patients of clinical hypothyroidism (23.64 ± 14.58) compared to patients of subclinical hypothyroidism (18.96 ± 20.49). Arousal index (77.5 ± 12.07) and snoring index (82.09 ± 132.34) are found to be elevated in patients of hypothyroidism. Snoring index is found to be significantly higher in patients of clinical hypothyroidism (183.96 ± 163.57) as compared to patients of subclinical hypothyroidism (82.09 ± 132.34).

Obstruction Sleep Apnea (OSA) is an under-diagnosed complication of hypothyroidism. Patients with risk factors, complaining of loud snoring and excessive day-time sleepiness should be evaluated for Obstruction Sleep Apnea (OSA). This greatly helps in improving their quality of life.