BACKGROUND AND PURPOSE:Quality of life (QOL) and sleepiness for patients with sleep apnea/hypopnea syndrome (SAHS) might improve with continuous positive airway pressure devices working in auto-adjust mode (autoCPAP) by allowing pressure modulations following patient needs. Clinical comparisons between devices driven by different algorithms are needed. METHODS:We compared the clinical effectiveness of fixed pressure CPAP and four different autoCPAP devices by assessing compliance and QOL (36-item short-form health survey [SF-36]). SAHS patients were randomly allocated to five groups. Polysomnography (PSG) was performed to titrate the effective pressure in the constant CPAP group and evaluate residual apnea/hypopnea index (AHI) under autoCPAP. Follow-up consisted of clinical visits at three and six months by homecare technicians who assessed compliance, symptom scores and SF-36 scores. A laboratory-based PSG using the same CPAP/autoCPAP device as at home was performed at six months. RESULTS:Eighty-three patients (mean age 56+/-10 yrs) with mean body mass index (BMI) 30.8+/-5.3 kg/m(2) and severe SAHS (mean AHI: 52.3+/-17.8/h) were included. There were no differences in clinical symptoms or QOL scores, and similar clinical and PSG improvements were seen in all groups. CPAP use was >5 h per night, without any significant difference between groups. CONCLUSIONS:AutoCPAP is equally as effective as fixed CPAP for long-term home treatment in severe SAHS patients.