Key Point

Seven clinical and psychological factors can predict 24% of the variance in CPAP compliance among apnea patients.

, sans-serif" size="-1" color="#336699">GLASGOW—Psychosocial variables are important influences on continuous positive airway pressure (CPAP) compliance and obstructive sleep apnea/hypopnea syndrome (OSAHS) outcome, yet they are often undervalued in medical practice. New research has highlighted the importance of these factors by identifying which OSAHS patients are most likely to comply with CPAP therapy, based on psychological and clinical characteristics.¹

Matthew Wild, DClinPsy, and colleagues performed a logistic regression analysis of psychological and clinical predictors of adherence to CPAP in 119 OSAHS patients who were followed for three months. The mean age of participants was 51; 79% were male, and 56% were current smokers. CPAP duration averaged 3.6 hours per night; 18% of patients received technical interventions, such as mask change or decongestant medication, to reduce CPAP side effects. “Social and cognitive variables influence CPAP use. These are modifiable variables that can impact levels of adherence,” explained Dr. Wild, a Lecturer in Clinical Psychology at the University of Glasgow.

Analysis revealed a seven-variable model of psychological and clinical components that predicted 24% of the variance in adherence. The model also predicted 75% of adherents and 53% of nonadherents. Psychological variables included having an internal locus of control, believing that powerful others (such as clinicians) control health, and perceiving health as valuable. Clinical variables included Epworth score, apnea/hypopnea index score, body mass index (BMI), and CPAP. Greater disease severity as assessed by Epworth and apnea/hypopnea index scores significantly and independently predicted higher adherence to CPAP. Other predictors of higher adherence included lower BMI, lower CPAP, stronger internal locus of control, less belief in powerful others, and greater health value.

The only statistically significant predictor of adherence was health value, or how important good health is to the patient. Yet, according to Dr. Wild, “it is important to consider the whole mix—psychological and physical factors all affect adherence.”

Dr. Wild’s model explained only 24% of the variance in CPAP use. What then, explains the rest of the variance? A trait called adaptive coping style, or the ability to adapt or change to manage disease, could positively influence CPAP compliance, Dr. Wild noted. Other research conducted by his group showed that patients with an adaptive coping style viewed the impact of OSAHS on their lives in practical terms. For example, they reported that their condition made them feel lethargic and affected their personal lives. They then took positive steps, such as adhering to CPAP, to change the negative effects of illness on their lives. Patients without this trait were less likely to adhere to CPAP.

Dr. Wild believes that similar research protocols could be used to predict adherence to physical therapy in COPD patients and self-management in asthma patients.

—Tamara Gibb

Reference
1. Wild MR, Engleman HM, Douglas NJ, Espie CA. Can psychological factors help us to determine adherence to CPAP? A prospective study. Eur Respir J. 2004;24:461-465.

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