Prevalence and Clinical Significance of Supine-Dependent Obstructive Sleep Apnea in Patients Using Oral Appliance Therapy

Study Objective: The prevalence of supine-dependent obstructive sleep apnea (sdOSA) in a general population ranges from 20% to 60%, depending on the criteria used. Currently, the prevalence and evolution of sdOSA once oral appliance therapy with a mandibular advancement device (OA(m)) has started is unknown. In addition, literature on the correlation between sdOSA and treatment success with OA(m) is not unequivocal. The first purpose of this study was to assess the prevalence of sdOSA before and under OA(m) therapy. Second, the conversion rate from non-sdOSA to sdOSA during OA(m) therapy was evaluated. The third and final goal was to analyze the correlation between sdOSA and treatment success with OA(m) therapy in the patient population. Methods: Two hundred thirty-seven consecutive patients (age 48 +/- 9 years; male/female ratio 173/64; AHI 20.1 +/- 14.7 events/h; BMI 27.2 +/- 4.3 kg/m(2)) starting OA(m) therapy were included. Results: The prevalence of sdOSA before the start of OA(m) therapy, ranged from 27.0% to 67.5%. The prevalence of residual sdOSA under OA(m) therapy in this study ranged from 17.5% to 33.9%. Second, the conversion rate from non-sdOSA to sdOSA ranged from 23.0% to 37.5%. Third, the presence of sdOSA at baseline was not a significant factor for treatment success with OA(m) therapy. Conclusions: The results of this study indicate that the prevalence of sdOSA before and under OA(m) therapy is relatively high. One-third of patients shift from non-sdOSA to sdOSA. Finally, treatment success for OA(m) therapy was not significantly correlated with the presence of sdOSA at baseline.