For patients with low-risk OSA, particularly those without excessive daytime sleepiness, CPAP may actually increase cardiovascular risk. In patients with low-risk OSA, CPAP increased cardiovascular events by ~22%, especially in non-sleepy individuals. CPAP lowers the risk of serious cardiovascular events in some patients with obstructive sleep apnea (OSA) but not others, according to a post-hoc analysis of three previously published trials. Low-risk OSA: patients with OSA but without either of these two markers. Non-sleepy patients with high-risk markers experienced 24% fewer cardiovascular events, while non-sleepy patients with low-risk markers experienced 30% more cardiovascular events.