Role of hypothyroidism in obstructive sleep apnea: a meta-analysis

Abstract

Objective: This study evaluates the role of hypothyroidism in obstructive sleep apnea (OSA) by comparing the OSA indices in hypothyroid OSA (OSA-HYPOT) with euthyroid OSA (OSA-EUTHY) patients. Methods: After literature search in several electronic databases and selection of studies by following eligibility criteria, meta-analyses of mean differences/standardized mean differences were performed to compare OSA indices at the time of diagnosis between OSA-HYPOT and OSA-EUTHY patients. Metaregression analyses were carried out to examine the relationship between age, BMI, sample size, and gender vs OSA indices in OSA-HYPOT patients. Results: Twelve studies and five case reports recruiting 192 OSA-HYPOT and 1423 OSA-EUTHY patients were included in the meta-analysis. Prevalence (mean ± SD) of clinical hypothyroidism in OSA patients was 8.12 ± 7.13% and that of subclinical hypothyroidism 11.07 ± 8.49%. Apnea–Hypopnea Index, time of sleep with oxygen desaturation <90%, and Epworth Sleepiness Scale were significantly higher in the OSA-HYPOT patients at diagnosis, whereas there was no significant difference in arousal index, respiratory disturbance index and sleeping efficiency between OSA-HYPOT and OSA-EUTHY patients. Body mass index was positively associated with Apnea–Hypopnea Index in OSA-HYPOT patients. Conclusions: Hypothyroidism is found to be associated with severity of OSA. However, obesity can be a confounder in the outcomes observed herein.

Keywords:

• Apnea
• hypopnea index
• epworth sleepiness scale
• hormonal replacement therapy
• hypothyroidism
• obstructive sleep apnea

Declaration of funding

This study was not funded.

Declaration of financial/other relationships

Mp.Z., W.Z., J.T., Mh.Z., Q.Z. and P.L. have disclosed that they have no significant relationships with or financial interests in any commercial companies related to this study or article.

CMRO peer reviewers on this manuscript have no relevant financial or other relationships to disclose.