Facial phenotype in obstructive sleep apnea-hypopnea syndrome: a systematic review and meta-analysis

This systematic review and meta-analysis explores the association between facial phenotype and obstructive sleep apnea-hypopnea syndrome in adults. A comprehensive electronic (Medline via Ovid, Scopus, and Embase) database and reference search were undertaken in relation to imaging modalities for surface craniofacial assessments in subjects with sleep apnea. The outcome measures were surface facial dimensions, morphology and profile. The quality of studies was assessed and a meta-analysis conducted. The studies were weighted using the inverse variance method, and the random effects model was used to analyse data. This systematic review identified eight case-control studies. In five studies (906 participants), adults with sleep apnea showed increased weighted mean differences in neck circumference by 1.26 mm (P = 0.0001) with extensive heterogeneity between studies (I² = 93%). Only two studies (467 participants) shared the following outcomes: mandible length, lower facial height, mandible width and anterior mandible height parameters. The pooled results demonstrated obstructive sleep apnea syndrome was associated with larger parameters than controls. In conclusion, the surface facial assessment was able to demonstrate some characteristic morphological features, facilitating a meta-analysis, in adults with obstructive sleep apnea-hypopnea syndrome. The strength of these findings, however, was limited by the heterogeneity of the studies precluding the identification of a clear phenotype.