Sex differences in mandibular repositioning device therapy effectiveness in patients with obstructive sleep apnea syndrome

Purpose: Mandibular repositioning devices (MRDs) are an effective treatment option for obstructive sleep apnea syndrome (OSAS), particularly in patients who refuse or cannot tolerate continuous positive airway pressure (CPAP). However, sex differences in the response to therapy and predictors of response are not clearly defined. This analysis of data from the long-term prospective ORCADES trial compared MRD efficacy in men and women with OSAS. Methods: The ORCADES study included patients with newly diagnosed mild-to-moderate or severe OSAS who refused or were non-compliant with CPAP. MRD therapy was titrated over 3–6 months. The primary endpoint was treatment success (≥ 50% decrease in apnea-hypopnea index (AHI)). Complete response was defined using a range of AHI cut-off values (< 5/h, < 10/h, < 15/h). Results: Overall treatment success rates were 89% in women and 76% in men (p = 0.019); corresponding rates in those with severe OSAS (AHI > 30/h) were 100% and 68% (p = 0.0015). In women vs. men, overall complete response rates at AHI cut-off values of < 5/h, <10/h, and < 15/h were 49 vs. 34% (p = 0.0052), 78 vs. 62% (p = 0.016), and 92 vs. 76% (p = 0.0032). On multivariate analysis, significant predictors of MRD treatment success were overbite and baseline apnea index in men, and neck circumference and no previous CPAP therapy in women. There were sex differences in the occurrence of side effects. Temporomandibular joint pain was the most common reason for stopping MRD therapy. Conclusions: MRD therapy was effective in women with OSA of any severity, with significantly higher response rates compared with men especially in severe OSAS. Trial registration: www.clinicaltrials.gov (NCT01326143).