CPAP Pressure for Prediction of Oral Appliance Treatment Response in Obstructive Sleep Apnea

Study Objectives: Mandibular advancement splints (MAS) are often preferred to CPAP treatment for OSA but are not always equally efficacious. High therapeutic CPAP pressure has been associated with MAS treatment failure in a Japanese population. We sought to assess the relationship between CPAP pressure and MAS treatment response in an Australian population. Methods: Therapeutic CPAP pressure and MAS treatment response were obtained from a one-month crossover trial of both treatments. Predictive utility of CPAP pressure to identify MAS treatment response was assessed. Results: Seventy-eight OSA patients were included (age 49.3 +/- 11.1 years, BMI 29.1 +/- 5.8 kg/m(2)) with predominantly moderate-severe OSA (AHI 30.0 +/- 12.7/h). CPAP pressure was lower in MAS responders (MAS AHI < 10/h) 9.7 +/- 1.6 vs. 11.7 +/- 2.4 cm H2O, p < 0.01, with area under ROC curve of 0.74 (95% CI 0.63-0.86), p < 0.01. The best cutoff value of 10.5 cm H2O useful for discriminating MAS responders and non-responders in the previous Japanese population, was inadequate for prediction in the current population (0.47 negative predictive value [NPV]). However a cutoff of 13 cm H2O identified MAS non-responders (1.0 NPV). Multivariate regression identified CPAP pressure (odds ratio [95% confidence interval] 0.53 [0.33-0.87], age (0.93 [0.87-0.99]) and AHI (0.92 [0.86-0.97]) as predictors of MAS treatment response (model r(2) = 0.54, p < 0.001). Conclusions: In Australian patients, the majority of whom are Caucasian, a higher therapeutic CPAP pressure requirement in conjunction with age and OSA severity characteristics may be useful to indicate likelihood of success with MAS as an alternative therapy.