Study Objectives: To determine the relative predictive utility of measures of behavior-change principles on treatment adherence in individuals with obstructive sleep apnea.

Methods: Ninety-eight participants with moderate to severe obstructive sleep apnea were recruited into this prospective longitudinal study. Participants were recruited from an academic sleep disorders center after having completed in-lab polysomnography and before initiating continuous positive airway pressure (CPAP) therapy. Participants were all treatment naïve. Measurements of behavior-change principles were taken at baseline and periodically throughout the 6-month follow-up. Adherence, measured by the amount of nightly use at the proper pressure, was monitored covertly by the CPAP machines. Results: Measures from 2 behavior-change theories (Transtheoretical Model and Social Cognitive Theory) were used in this study: readiness to change, perceived self-efficacy, and decisional balance. The results from the present study suggest that measures of behavior change predict CPAP adherence at 6 months posttreatment when assessed at 1 week and at 3 months posttreatment. When these measures are assessed at baseline, however, they are not predictive of CPAP use at 6-months. These measures do not improve upon the prediction of 6-month adherence provided by previous adherence. Conclusions: While the readiness, decisional balance, and self-efficacy measures were all predictive of adherence, the strongest predictive utility came from measures of readiness and self-efficacy. Those individuals who use CPAP more were more likely to rate themselves as ready and confident in their ability to use CPAP. The utility of these measures was diminished when controlling for previous use. Our intention, however, was to study modifiable risk factors for poor adherence. Principles of behavior change, which are often used in adherence research in other medical populations, are thought to be modifiable with behavioral interventions and show promise for improving adherence.