The aim of this study was to investigate the potential polysomnographic predictors of CPAP adherence using polysomnographic parameters at the time of obstructive sleep apnea diagnosis that distinguished between REM and NREM sleep. This was a retrospective cross-sectional study of 173 patients. Patients who used CPAP for more than 4 hours per night for at least 70% of nights over a 6-month period were considered to have good adherence. The poor adherence group included those who had used CPAP for 6 months from initiation, but did not fulfill the definition of good adherence or gave up the treatment within 6 months of treatment initiation. Of the 173 participants, 44 patients had good CPAP adherence and 129 patients had poor adherence. Univariate analysis showed that patients with good adherence had significantly higher apnea-hypopnea index during NREM sleep (p = 0.043), oxygen desaturation index during NREM sleep (p = 0.011), and cumulative percentage of time spent at saturations below 90% (CT90) during NREM sleep (p < .001). In multiple logistic regression analysis including all variables, CT90 during NREM sleep was the only factor independently associated with CPAP adherence (odds ratio, 0.693; 95% confidence interval, 0.582-0.824; p <.0001). The area under the receiver-operating characteristic curve of CT90 during NREM sleep was 0.823 (95% confidence interval, 0.745-0.901).Evaluating NREM sleep is important in reliably predicting CPAP adherence using polysomnographic parameters. CT90 during NREM sleep was the best predictor of CPAP adherence.
Keywords: adherence; continuous positive airway pressure; obstructive sleep apnea; polysomnography.