PURPOSE: Short-term trials suggest that autoCPAP is an effective treatment for the obstructive sleep apnea syndrome (OSA). Whether it is equivalent to CPAP with fixed pressure in the longer term is not known. Therefore, we initiated a multi-center trial comparing autoCPAP and fixed CPAP therapy during 2 years.
METHODS: OSA patients (apnea/hypopnea index AHI>10/h, Epworth score >8) were randomized in a parallel design trial to autoCPAP or fixedCPAP at the 90.%ile of mask pressure during a 2-4 weeks autoCPAP adaptation period. Outcomes included sleepiness, quality of life, AHI and blood pressure at baseline and at 1, 3, 12 and 24 months. Equivalence statistics were computed according to Jones, BMJ 1996;313:550.
RESULTS: Data from the first 105 patients (mean age±SD 57±11y) included in this ongoing trial and followed for >12 months are reported. In the autoCPAP group (n=54), Epworth scores at baseline and 12 months were 13.8±3.6 and 7.1±3.5; corresponding AHI were 61.1±24.6/h and 7.0±11.1/h (P<0.001 vs. baseline, both instances). In the fixed CPAP group (n=51) Epworth scores at baseline and 12 months were 13.5±3.3 and 7.7±3.7; AHI were 54.6±22.4/h and 7.7±10.6/h (P<0.001 vs. baseline, both instances, P=NS vs. autoCPAP). 95% confidence intervals of differences between treatment effects of the two CPAP modalities did not exceed predefined equivalence ranges for the Epworth score (< 2 points), SF-36 vitality (<10 points), AHI (<5/h), oxygen saturation (<2%), sleep resistance time (OSLER <3min), and 24h blood pressure (<3 mmHg). Treatment adherence was similar on autoCPAP (5.9±0.9h/night) and fixed CPAP (6.3±1.3h/night, P=NS) but mask pressure was lower on autoCPAP (8.4±2.4 vs. 10.6±2.0 cmH2O, P<0.05).
CONCLUSION: Our data demonstrate therapeutic equivalence of autoCPAP and fixed CPAP during at least one year in terms of improving symptoms, quality of life, breathing disturbances, vigilance and blood pressure in patients with OSA.
CLINICAL IMPLICATIONS: Since autoCPAP does not require initial mask pressure titration and subsequent adapatation it might be a conventient long-term treatment for OSA with the potential to save costs.
DISCLOSURE: Konrad Bloch, Grant monies (from sources other than industry) The study was supported in part by the Swiss National Science Foundation and the Lung Ligue of Zurich.; Grant monies (from industry related sources) The study was supported in part by ResMed and the Respironics Foundation.; No Product/Research Disclosure Information