Determinants of nasal CPAP compliance

Obstructive sleep apnea is a prevalent condition with potentially serious medical and psychosocial consequences. Nasal continuous positive airway pressure (CPAP) is the treatment-of-choice and has been shown to reduce the frequency of nocturnal respiratory events, improve sleep architecture and decrease daytime sleepiness. Patient compliance with CPAP is disappointingly low. Previous studies examining determinants of CPAP compliance have limited the variables studied to patient (sociodemographic), disease status, and treatment variables, with few reliable determinants found.

The purpose of the current study was to investigate the relationship between objectively measured CPAP compliance and variables from social cognitive theory (SCT) and the transtheoretical model (TM). Scales that measure variables from each model were developed and reliability evaluated. The relationship between the SCT and TM variables and compliance at 1-month post-CPAP-fitting was prospectively evaluated on 51 first-time CPAP users. SCT and TM variables were measured on the day of CPAP-fitting, at 1-week post-CPAP-fitting, and at 1-month post-CPAP-fitting.

SCT variables measured 1-week post-CPAP-fitting (R(2)=0.261, P=0.001) and TM variables measured 1-week post-CPAP-fitting (R(2)=0.17, P=0.002) accounted for a statistically significant amount of variance in objective CPAP compliance measured at 1 month. The decisional balance index (from TM) individually accounted for a significant amount of variance in objective CPAP compliance in the above analyses.

The ability of these new behavior change scales to predict CPAP compliance provides us with a new direction of research to better understand factors associated with compliance. The principal advantage of these theory-driven and empirically validated scales are that they measure modifiable factors that can provide the basis for sound interventions to improve CPAP compliance.