SA2 - Beyond the Apnea-Hypopnea Index: Pre-Treatment Oxygen Nadir as a Superior Predictor of Mandibular Advancement Device Success

Abstract: Mandibular advancement devices (MADs) are an established treatment for obstructive sleep apnea (OSA), yet predicting which patients will respond favorably remains challenging. The apnea-hypopnea index (AHI) is commonly used to guide treatment decisions, but it may not fully capture physiologic factors that influence treatment success. This study evaluated whether pre-treatment oxygen nadir provides greater predictive value for MAD treatment outcomes than baseline AHI.

A retrospective review of patients treated with MAD therapy for OSA between January 1, 2015, and October 10, 2025, was performed. Treatment success was defined as a post-treatment AHI < 10 events per hour or a reduction in AHI greater than 50% from baseline. Logistic regression analysis was used to assess the predictive value of baseline AHI and pre-treatment oxygen nadir. Of 151 patients identified, 48 had complete baseline and post-treatment sleep study data including oxygen nadir and were included in the final analysis.

In univariate analysis using t-test, patients with successful treatment demonstrated higher mean pre-treatment oxygen nadir values than those with treatment failure (85.3 ± 5.6% vs 81.4 ± 6.2%, P = .051). Baseline AHI and age were not significantly different between groups. Multivariable logistic regression was utilized, adjusting for baseline severity, which demonstrated that pre-treatment oxygen nadir was a significant independent predictor of treatment success (adjusted odds ratio 1.17 per percentage increase; 95% CI: 1.02-1.34; P = .027). Baseline AHI was not a significant predictor (adjusted odds ratio 1.04; 95% CI: 0.98-1.11; P = .168). Patients with a baseline oxygen nadir =80% achieved a treatment success rate of 79.5%, compared with 66.7% among those with more severe desaturation.

These findings suggest that physiologic measures of nocturnal hypoxemia may be more informative than traditional frequency-based metrics when predicting response to oral appliance therapy. Categorizing patients by hypoxemia incorporates functional capacity and respiratory reserve, markers often overlooked by frequency-based metrics. Incorporating oxygen nadir into pre-treatment evaluation may improve patient selection for MAD therapy and lead to more personalized treatment strategies for individuals with OSA.



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