Study objectives: The purpose of this study was to evaluate the Self-Efficacy Measure for Sleep Apnea (SEMSA) designed to assess adherence-related cognitions.
Design: Subjects completed the questionnaire prior to the initiation of continuous positive airway pressure (CPAP) treatment. Test-retest reliability of the instrument was evaluated by having a subset of subjects complete the SEMSA a second time at home, 1 week later, returning the questionnaire by mail.
Patients: 213 subjects with newly diagnosed obstructive sleep apnea were recruited from the clinic populations of 2 sleep disorders centers.
Measurements and results: Content validity was confirmed by a panel of expert judges. Confirmatory factor analysis validated the 3 a priori sub-scales: risk perception, outcome expectancies, and treatment self-efficacy. The internal consistency of the total instrument was 0.92. Test-retest reliability coefficients (N = 20) were estimated to be 0.68, P = 0.001, for Perceived Risk; 0.77, P more more than 0.0001, for Outcome Expectancies; and 0.71, P = 0.0005, for the Treatment Self-Efficacy subscale. Subject responses indicated that approximately half of the subjects did not perceive problems with concentration, sexual performance, sleepy driving, or an accident as related to sleep apnea. More than 60% of the subjects acknowledged most of the benefits of CPAP presented to them, but only 53% associated CPAP use with enhanced sexual performance. Frequently identified barriers to treatment use were nasal stuffiness, claustrophobia, and disturbing bed partner sleep.
Conclusion: These findings indicate that the SEMSA has strong psychometric properties and has the potential for identifying patient perceptions that may indicate those most likely to not adhere to treatment.