Introduction Continuous Positive Airway Pressure (cpap) Has Been Demonstrated as an Effective Treatment for Patients with Obstructive Sleep

CONTINUOUS POSITIVE AIRWAY PRESSURE (CPAP) HAS BEEN DEMONSTRATED AS AN EFFECTIVE TREATMENT FOR PATIENTS WITH OBSTRUCTIVE SLEEP APNEA (OSA).1 However, poor compliance with CPAP has been identified as a significant obstacle in the successful treatment of OSA.2-7 The degree of compliance with CPAP is a significant factor in determining improvement in daytime sleepiness and other health-related outcomes,8 and it has been shown that compliance during the initial months of therapy predicts long-term use.9 Most studies in the United States have estimated that patients who have been prescribed CPAP use their machines between 4.5 and 5.5 hours per night.2,7,10-15 Considering that laboratory studies of sleep restriction have demonstrated significant impairment in objective measures of alertness following as little as 1 night with 6 hours of sleep,16 this level of nightly CPAP use may not be adequate to eliminate the behavioral morbidity associated with OSA. While studies have shown that beneficial effects are produced with compliance rates as low as 5.1 hours per night,17 the degree of compliance required to “normalize” function has not been adequately determined. Indeed, significant daytime sleepiness can be present in patients who have average nightly compliance rates of up to 6.1 hours per night.18 The low compliance rates of OSA patients to CPAP treatment have led investigators to propose various methods for improving compliance in this patient population. Specifically, extensive CPAP education programs,8,14,19-22 intensive outpatient monitoring schedules,23 and sideeffect reduction techniques13,24 have all met with limited success. Although in clinical practice, benzodiazepines are sometimes prescribed to patients to increase tolerance of the CPAP apparatus and to enhance compliance during the initial phases of treatment, the effect of this intervention on long-term compliance rates has not been studied. In one recent long-term randomized cross-over trial of auto-titrating CPAP (auto-PAP) versus standard CPAP, individuals used the auto-PAP more than the standard CPAP and, based on dropout data, individuals using auto-PAP were more likely to continue treatment.25 However, auto-PAP was still used for only approximately 6 hours. Thus, additional methods for improving CPAP compliance are needed. Determining the specific reasons for compliance could help provide better ways to improve treatment adherence to CPAP. Several studies have been directed toward identifying individual patient factors associated with compliance.6,26-31 Studies have focused on clinical parameters and disease severity both before and after treatment3,27,28 and psychological measures,29-31 as well as side effects associated with CPAP use.6 Each of these areas of investigation has produced equivocal findings, although there appears to be increasing evidence that greater disease severity is associated with higher levels of compliance.3,7,32,33 Not surprisingly, there appear to be multiple factors associated with adherence to CPAP treatment. One area that has not been studied extensively is the investigation of factors associated with a patient’s initial exposure to CPAP that may influence compliance. Clearly, the degree of long-term compliance with a treatment regimen will be partly dependent upon a patient’s initial acceptance or rejection of the treatment modality. Any factors that significantly affect a patient’s initial experience with CPAP could have an impact on her or his subsequent compliance. Thus, the present study was undertaken to investigate possible associations between polysomnogram (PSG) sleep parameters obtained during patients’ initial CPAP titration night and subsequent objective measures of CPAP compliance. We hypothesized that nocturnal PSG variables that represent improved sleep during titration would be positively related to compliance. That is, patient compliance will be related to the degree of improvement in sleep that patients experience during their initial titration night.