Mandibular advancement device (MAD) therapy is the most commonly used non-continuous positive airway pressure (CPAP) treatment for obstructive sleep apnea (OSA). Although OSA patients prefer MAD over CPAP, on average over one third have minimal or no major reduction in OSA severity with MAD therapy. Improved understanding of responder characteristics (or “phenotypes”) to MAD may facilitate more efficient use of limited medical resources and optimize treatment efficacy.

The aim of this review is to describe the baseline phenotypic characteristics of responders to MAD therapy in OSA patients. Pubmed, Web of Science, EMBASE, Scopus were searched for eligible studies published until Feb 2019. A total of 650 studies were identified. 41 studies were included in this review and meta-analysis. The quality of the studies was assessed using the risk of bias assessment tool for non-randomized studies (RoBANS). Based on meta-analysis, the responders to MAD therapy had certain clinical phenotypic characteristics: lower age (95% CI: −4.55 to −1.62, p < 0.00001), female (95% CI: 0.56 to 0.91, p = 0.006), lower body mass index (95% CI: −2.80 to −1.11, p < 0.00001), smaller neck circumference (95% CI: −1.57 to −0.52, p < 0.00001), lower apnea-hypopnea index (95% CI: −7.23 to −1.89, p < 0.00001), a retracted maxilla and mandible, a narrower airway and a shorter soft palate than non-responders. The above-mentioned phenotypic responder characteristics provides useful information for the clinician when considering prescribing MAD therapy for OSA patients.