fixed and autoadjusting continuous positive airway pressure treatments are not similar in reducing cardiovascular risk factors in patients with obstructive sleep apnea background a strong association between obstructive sleep apnea osa and the risk for cardiovascular and cerebrovascular diseases has been reported continuous positive airway pressure cpap is the firstline therapy for osa able not only to reduce daytime sleepiness but also to improve cardiovascular and metabolic outcomes autoadjusting cpap apap an alternative treatment to cpap can reduce osa symptoms while increasing longterm cpap compliance without the high costs of cpap titration however no data are available on the effects of apap on cardiovascular risk factorsmethods we performed standard full polysomnography obtained plasma levels of glucose insulin and creactive protein crp and measured systolic bp sbp and diastolic bp dbp in 31 patients with newly diagnosed severe osa after standard cpap titration all subjects were randomized to cpap or apap treatment measurements were obtained at baseline and after 3 months of treatmentresults the two groups were similar in terms of age sex body mass index bmi and severity of osa sbp dbp heart rate hr homeostasis model assessment index homair and crp were similar in the two groups after 3 months of treatment bmi hr and compliance to therapy were also comparable osa indexes were significantly reduced in both groups significant reductions in sbp dbp and homair were observed in the cpap group but not in the apap group while crp plasma levels were similarly reducedconclusions our results suggest that cpap and apap despite significant effects on osa indexes and symptoms do not improve cardiovascular risk factors in the same fashion