Severity of individual obstruction events increases with age in patients with obstructive sleep apnea

Background: Age is a risk factor of obstructive sleep apnea (OSA). It has been shown that OSA progresses over time, although conflicting results have been reported. However, the effect of age on the severity of OSA and individual obstruction events has not been investigated within different OSA severity categories by taking the most prominent confounding factors (i.e., body mass index, gender, smoking, daytime sleepiness, snoring, hypertension, heart failure, and proportion of supine sleep) into account. Methods: Polygraphic data of 1090 patients with apneaehypopnea index (AHI) >= 5 were retrospectively reanalyzed. The effect of age on the severity of OSA and obstruction events was investigated in general, within different OSA severity categories, and in different age groups (age < 40, 40 <= age < 50, 50 <= age < 60, and age <= 60 years). Results: In the whole population, AHI and durations of apneas, hypopneas, and desaturations increased with increasing age (B >= 0.108, p <= 0.010). In more detailed analysis, AHI increased with age only in the moderate OSA category (B = 0.075, p = 0.022), although durations of apneas increased in mild and severe OSA categories (B >= 0.076, p <= 0.038). Furthermore, durations of hypopneas increased with age in mild and moderate OSA categories (B >= 0.105, p <= 0.038), and durations of desaturations (B >= 0.120, p <= 0.013) in all OSA severity categories. AHI was not statistically significantly different between the age groups, although durations of obstruction events tended to increase towards older age groups. Conclusion: As obstruction event severity was more strongly dependent on the age than it was dependent on AHI, considering the severity of obstruction events could be beneficial while estimating the long-term effects of the treatments and prognosticating the disease progression. (C) 2017 Elsevier B.V. All rights reserved.