Impact of age on intermittent hypoxia in obstructive sleep apnea: a propensity-matched analysis

Purpose To determine independent relationship of aging with chronic intermittent hypoxia, we compared hypoxia-related polysomnographic variables of geriatric patients (aged ≥ 65 years) with an apnea–hypopnea index (AHI)-, gender-, body mass index (BMI)-, and neck circumference-matched cohort of non-geriatric patients. Methods The study was conducted using clinical and polysomnographic data of 1280 consecutive patients who underwent complete polysomnographic evaluation for suspected sleep-disordered breathing (SDB) at a single sleep disorder center. A propensity score-matched analysis was performed to obtain matched cohorts of geriatric and non-geriatric patients, which resulted in successful matching of 168 patients from each group. Results Study groups were comparable for gender ( P = 0.999), BMI ( P = 0.940), neck circumference ( P = 0.969), AHI ( P = 0.935), and severity of SDB ( P = 0.089). The oximetric variables representing the duration of chronic intermittent hypoxia such as mean ( P = 0.001), the longest ( P = 0.001) and total apnea durations ( P = 0.003), mean ( P = 0.001) and the longest hypopnea durations ( P = 0.001), and total sleep time with oxygen saturation below 90% ( P = 0.008) were significantly higher in the geriatric patients as compared with younger adults. Geriatric patients had significantly lower minimum ( P = 0.013) and mean oxygen saturation ( P = 0.001) than non-geriatric patients. Conclusions The study provides evidence that elderly patients exhibit more severe and deeper nocturnal intermittent hypoxia than the younger adults, independent of severity of obstructive sleep apnea, BMI, gender, and neck circumference. Hypoxia-related polysomnographic variables in geriatric patients may in fact reflect a physiological aging process rather than the severity of a SDB.