Disparities in oxygen saturation and hypoxic burden levels in obstructive sleep apnoea patient’s response to oral appliance treatment

BACKGROUND: Oxygen saturation indices show a strong correlation with long‐term health outcomes. Nonetheless, evidence on the relationship between reduction in respiratory events and increase in oxygenation levels following oral appliance (OA) treatment is scarce. OBJECTIVES: To verify the relationship between reduction in the apnoea‐hypopnoea index (AHI) and oxygen saturation levels following OA treatment, we have conducted an evaluation of polysomnography (PSG) and clinical parameters associated with the improvement of oxygen desaturation. METHODS: OSA patients (n = 48) who received an OA and had pre‐ and post‐treatment PSG were classified into three responder groups according to the change in AHI and min O(2) post‐treatment: responder(AHIonly) (decrease in AHI of ≥50% but increase in min O(2) level of <4% or decrease); responder(MinO2only) (increase in min O(2) level of ≥4% but decrease in AHI <50% or increase) and responder(Congruous) (decrease in AHI of ≥50% and increase in min O(2) level of ≥4%). Various demographic and PSG variables were statistically compared among groups. RESULTS: There were 26 (54.17%) responder(AHIonly), 9 (18.75%) responder(MinO2only) and 13 (27.08%) responder(Congruous). Pre‐treatment min O(2) was significantly lower in responder(MinO2only). A higher pre‐treatment min O(2) showed a significant correlation with a smaller amount of change in mean O(2) (r = −.486) and min O(2) (r = −.764) with treatment. Pre‐treatment min O(2) showed the strongest ability to predict those who would show a ≥4% min O(2) increase following treatment. CONCLUSION: Certain patients do not show sufficient decrease in hypoxaemia in spite of the improvement in AHI. Pre‐treatment min O(2) should be considered in OA treatment planning regarding its close relation to improvements in oxygenation levels with treatment.