An obese 56-year-old married man complains of daytime sleepiness, and his wife states that he snores, snorts, and gasps during nighttime sleep. What polysomnographic finding is needed to confirm the diagnosis of obstructive sleep apnea hypopnea?

Choice A reason: A diagnosis of obstructive sleep apnea (OSA) is confirmed when polysomnography reveals at least 5 episodes of apnea or hypopnea per hour of sleep in the presence of symptoms such as snoring, gasping, or daytime sleepiness. This threshold is consistent with clinical guidelines and reflects mild OSA. Choice B reason: While 15 or more episodes per hour indicate moderate to severe OSA, the minimum diagnostic threshold is 5 events per hour with associated symptoms. Therefore, this choice is overly restrictive and not the best initial diagnostic criterion. Choice C reason: Polysomnography is the gold standard for diagnosing OSA. Clinical symptoms alone are insufficient for a definitive diagnosis, especially when treatment decisions depend on severity classification. Choice D reason: Resolution of apneas/hypopneas with CPAP confirms treatment efficacy but does not establish the initial diagnosis. This finding is relevant after diagnosis and during titration studies, not for confirming OSA.