Predictable Factors of Residual Sleepiness in Auto-PAP Users With Obstructive Sleep Apnea

Choi, Su Jung; Koo, Dae Lim; Joo, Eun Yeon; Hong, Seung Bong

Abstract

BACKGROUND
Some patients with obstructive sleep apnea (OSA) remain sleepy despite adequate use of nasal positive airway pressure (PAP). To investigate the clinical and polysomnographic factors related to residual daytime sleepiness in OSA patients with adequate PAP-treatment for more than 3 months.
METHODS
We enrolled consecutively 101 patients, who were diagnosed with moderate to severe OSA by overnight polysomnography. All of them complained of daytime sleepiness and started using nasal Auto-PAP (APAP). Patients who had used APAP adequately (> or =70% of nocturnal sleep time, > or =5 days a week) for more than 3 months were divided into a group with residual excessive sleepiness (RES; Epworth sleepiness scale, ESS > or =10) and a group without RES (Non-RES) (ESS<10). Clinical and polysomnographic variables were compared between two groups.
RESULTS
Fifty-six patients (55.4%, 56/101) who had used APAP adequately (mean 9.6 months) were enrolled finally. Twenty (35.7%) had RES (mean ESS: 15.2 decreased to 12.4 after PAP therapy) while 36 had no RES (mean ESS: 13.1-->6.0). Hypertension was more frequent in RES patients. Furthermore, RES patients were sleepier than Non-RES ones before APAP treatment started. Other clinical, demographic, polysomnography findings and compliance of APAP were not different between two. On multivariate logistic analysis regression, baseline ESS (odd ratio [OR] 1.34 [1.07-1.67]), history of hyperlipidemia (OR 5.04 [1.14-22.33]) were significantly associated with RES.
CONCLUSIONS
Our findings showed that 35.7% of OSA patients remained sleepy after an adequate PAP therapy. Predictors of RES were a history of hyperlipidemia and a higher baseline ESS.