Brief SummaryCurrent knowledge/study rationale Sleep-Disordered Breathing (SDB) in general and Central Sleep Apnea (CSA) in particular are known to increase with advancing age. The information concerning the morbidity and mortality associated with CSA in older populations is scarce and inconsistent. It is not known if CSA-related mortality is greater than Obstructive Sleep Apnea (OSA) related mortality in the elderly. Study impactOur study using a prognostic mortality risk index demonstrates that CSA diagnosed by full polysomnography is a major and independent risk factor for mortality in older adults. Untreated CSA compared with OSA is also significantly associated with stroke and hypertension. IntroductionThe prevalence of Sleep-Disordered Breathing (SDB), defined as an Apnea-Hypopnea index (AHI) of 15 or greater, is 23% in the community-dwelling older over the age of 70 [1]. Central Sleep Apnea (CSA), a form of SDB, can affect more than one third of these elderly patients with SDB [1]. The prevalence, severity and costs of CSA will likely escalate as the older adult population increases in number and lives longer.CSA is characterized on the polysomnogram by recurrent cessation of respiration during sleep with no associated ventilatory effort. In contrast obstructive sleep apnea (OSA) is defined as repetitive episodes of upper airway obstruction with ongoing respiratory efforts [2]. In OSA patients the repetitive upper airway collapse occurs during sleep because negative pressure generated during inspiration is not effectively counteracted by splinting by pharyngeal dilators, especially when narrowing occurs as a result of excessive soft tissue (e.g. obesity, loss of soft tissue elasticity related to age) or vulnerable craniofacial anatomy (e.g. edentulous older adults). In both cases, the Continuous Positive Airway Pressure (CPAP) is the most widely used treatment even in older adults. Furthermore, bilevel positive airway pressure (BiPAP) in a spontaneous-timed mode and Adaptive Servo-Ventilation (ASV) which generates positive airway pressure with variable pressure in response to a patient's expiration are increasingly recommended in order to ameliorate central respiratory events related to chronic heart failure. AbstractObjectives: To assess cardiovascular morbidity and prognostic mortality risk in older patients with CSA in comparison to those with OSA and without any SDB (apnea-hypopnea index <15/hour).Background: Sleep-Disordered Breathing (SDB), including both Central Sleep Apnea (CSA) and Obstructive Sleep Apnea (OSA), is a prevalent condition in older adults. In contrast to OSA, the information concerning the morbidity and mortality associated with CSA is scarce and inconsistent.