Controlled, prospective trial of psychosocial function before and after continuous positive airway pressure therapy.
McFadyen TA., Espie CA., McArdle N., Douglas NJ., Engleman HM.
The aim of the study was to investigate psychosocial function before and after continuous positive airway pressure (CPAP) therapy, and establish the determinants and consequences of objective CPAP use. In a prospective, parallel-group study, changes in psychosocial scores were compared with conservative management or CPAP therapy for the sleep apnoea/hypopnoea syndrome (SAHS). Patient/partner couples from the top (CPAP treated, n=44) or bottom (conservatively treated, n=25) of a CPAP waiting list rated marital satisfaction (evaluation and nurturing relationship issues, communication and happiness (ENRICH), behavioural questionnaire), health/functional status (Short-Form-36 Health Survey, functional outcomes of sleep questionnaire) and sleepiness (Epworth sleepiness scale). Both groups' ratings at baseline were completed while on conservative therapy. Baseline variables did not differ between groups. At follow-up, all seven summary psychosocial scores were statistically better in CPAP-treated patients, effect sizes (ES) ranging from moderate (0.5 SD: marital satisfaction) to very large (>1.0 SD: patients health, functional status and sleepiness scores). Scores in conservatively-treated patients deteriorated to a small or moderate degree (ES -0.2- -0.7 SD), while those in the CPAP-treated group improved to a larger degree (0.3-1.3 SD). Baseline polysomnographical and psychosocial scores, including marital satisfaction, did not predict objective CPAP use (r<0.3). CPAP use was modestly correlated (r=0.3-0.6) with improvement in all psychosocial areas. Continuous positive airway pressure produced statistically and clinically significant psychosocial improvements, some of large magnitude, in psychosocial function. Determinants of usage were not identified, but benefits and usage were positively correlated.