The Effect of CPAP in Normalizing Daytime Sleepiness, Quality of Life, and Neurocognitive Function in Patients with Moderate to Severe OSA

PATIENTS WITH OBSTRUCTIVE SLEEP APNEA (OSA) and is widely accepted as the most efficacious therapy for OSA. Patel and colleagues performed a meta-analysis showing that CPAP reduced the Epworth Sleepiness Scale (ESS) score an average of 2.9 points more than did placebo (P < 0.001) in patients with OSA. Patients with moderate to severe OSA had a greater fall in ESS than did those with mild OSA. These are important questions because it is known that CPAP adherence varies widely among patients. 2 For example, in an early study, Weaver et al. reported that, among 32 patients using CPAP, half were consistent users, applying CPAP on more than 90% of nights for an average of 6.2 hours per night, whereas the other half were intermittent users who had a wide range of daily use, averaging 3.5 hours per night. In addition, although many patients present with excessive daytime sleepiness (EDS), this is a relatively nonspecific symptom. In the Sleep Heart Health study, the percentage of subjects with EDS, defined as an ESS score greater than 10, was increased from 21% in subjects with an AHI of less than 5 to 35% in those with an AHI of at least 30. Thus, many people without OSA were still subjectively reporting EDS. In a population-based study, Bixler and colleagues 6 found that depression was the most significant risk factor for EDS, followed by, in decreasing levels of importance, body mass index, age, typical sleep duration, diabetes, smoking, and finally OSA. ] If these abnormalities