Relationship between OSA pathophysiological phenotypes and treatment response to mandibular advancement devices: a pilot study

Study Objectives: We assessed whether critical pathophysiological phenotypes predict treatment response in patients with obstructive sleep apnea using a mandibular advancement device (MAD). Methods: Thirty-one patients with obstructive sleep apnea were treated with a MAD. Individuals were categorized and graded into 4 pathophysiological phenotypes based on polysomnographic features (anatomical, ventilatory control, arousal threshold, and muscle responsiveness). Morpho-anthropometric data were additionally assessed. Patients were classified as responders or nonresponders. Associations between polysomnographic phenotypes and treatment response were documented, as were morpho-anthropometric data and their impact on therapeutic success. Results: There was a male predominance (64.5%), with a median age of 49 years (25th percentile: 40; 75th percentile: 55), body mass index = 27.4 kg/m(2) (25th percentile: 26; 75th percentile: 28.8), and apnea-hypopnea index of 18.2 events/h (25th percentile: 11.7; 75th percentile: 27.6). The majority of patients treated with a MAD (58%) were good responders (68.0% mild and moderate vs 16.7% severe). Treatment response was associated with shorter intermolar and interpremolar distances in the lower arch (P = .0092 and .0129). Rapid eye movement sleep apnea-hypopnea index and MAD-related treatment response were inversely correlated (P = .0013). Favorable anatomical (P = .0339) and low muscle response (P = .0447) phenotypes were correlated with outcomes. Conclusions: According to our results, a favorable response occurred in a better "anatomical phenotype" and in the worse "muscular responsiveness phenotype" according to polysomnographic data. Furthermore, other favorable predictors, such as a rapid eye movement sleep apnea-hypopnea index < 16 events/h and a smaller distance between lower molars and premolars, were found. These findings indicate that clinical and polysomnographic aspects can discriminate phenotypes that may guide decisions on MAD treatment for obstructive sleep apnea.