Effect of continuous positive airway pressure vs placebo continuous positive airway pressure on sleep quality in obstructive sleep apnea

Study objectives: Continuous positive airway pressure (CPAP) therapy has be come the treatment of choice for obstructive sleep apnea (OSA). However, th e efficacy of CPAP therapy has not been evaluated against a suitable contro l. We investigated the effectiveness of CPAP therapy in improving sleep qua lity in patients with OSA. We hypothesized that CPAP improves sleep quality . Patients: Forty-eight CPAP-naive OSA patients were evaluated. None were rec eiving antihypertensive medications, and none had major medical illnesses. Design: Patients were randomized to receive either CPAP or placebo CPAP (CP AP at an ineffective pressure) for 7 days in a double-blind fashion. Forty- one patients completed the protocol. Sleep quality variables, arousals, sle ep arterial oxygen saturation (SaO(2)), and respiratory disturbance index ( RDI) were assessed at baseline, after I day of treatment, and after ? days of treatment. Repeated measures analysis of variance was used to evaluate t he effects of treatment, time, and the interaction of the two. Results: As expected, CPAP lowered RDI and number of arousals, and increase d Sao, over time (p = 0.001), Contrary to expectations, both CPAP and place bo CPAP had comparable effects on sleep quality as assessed by sleep archit ecture, sleep efficiency, total sleep time, and wake after sleep onset time . Conclusions: This study confirms the effectiveness of CPAP in lowering the number of arousals and the RDI, and in raising SaO(2). However, our data su ggest that short-term CPAP is no different than placebo in improving sleep architecture. Further evaluation of the effectiveness of CPAP using a suita ble placebo CPAP in prospective randomized studies is needed.