The Clinical Significance of Apneas Versus Hypopneas: Is There Really a Difference?

Abstract

Introduction Obstructive sleep apnea is diagnosed by identifying obstructive apneas and hypopneas, but no study has shown that it is necessary to distinguish these events from each other. Our goal was to analyze results from polysomnograms to determine if adverse health outcomes were more likely in patients with higher apnea indices relative to their hypopnea indices. Our hypothesis was that scoring apneas separately from hypopneas has no predictive value. Methods A retrospective case series was performed for consecutive diagnostic and split-night polysomnograms with apnea-hypopnea indices greater than five per hour. Clinical data reviewed included the presence of cardiovascular diseases, hypertension, depression, and migraine. Both univariate and multivariate analyses were performed to look for correlations between polysomnographic indices and the comorbidities. Results Three hundred fifty-one records were included. Univariate analysis showed no significant difference between the apnea index (AI) and hypopnea index (HI) based on the presence of any of the comorbidities. Multivariate logistic regression also indicated no significant association between indices and comorbidities, aside from one statistically significant correlation between a higher HI and depression. Conclusions Clinical comorbidities are no more likely in patients with higher apnea indices than hypopnea indices. While apneas are considered a more severe form of obstruction, this distinction does not have any known clinically predictive value. This finding raises the question as to whether scoring hypopneas and apneas as different events on polysomnograms is necessary or helpful. Scoring apneas and hypopneas as “obstructions” could save resources and increase inter-scorer reliability.

Respiration-Triggered Olfactory Stimulation Reduces Obstructive Sleep Apnea Severity – A Prospective Pilot Study

“…Odor perception is directly linked to the amount of air entering the nostrils 52 and thus we hypothesized that olfactory stimulation will have a greater influence on hypopnea events in comparison to apnea events. A non-parametric repeated measures ANOVA (Friedman test) with conditions of ‘Stimulation (Odor/Control), and ‘Index’ (Apnea Index/Hypopnea Index) uncovered a main effect of ‘Stimulation’ in which ‘Odor’ nights were associated with lower AI and HI indices, (F = 3.56, Kendall’s W = −18.65, p = 0.021), and a main effect of ‘Index’ in which hypopneas were more frequent than apneas (F = 6.7, Kendall’s W = −20.78, p < 0.001), in line with previous findings 53 . However, in contrast to our hypothesis there was no interaction between ‘Stimulation’ and ‘Index’ (computed on the difference between (Odor - Control) per index, non-parametric test: z =-0.052, p = 0.85, BF 10 = 2.49).…”

Prevalence of Obstructive Sleep Apnea in the Young Adult Population: A Systematic Review

“…Several factors lead to discrepancies between the reported results: hypopnea definition, AHI threshold, and type of device. Firstly, the hypopnea definition was modified throughout the years and may result in a different number of the total AHI [ 37 , 38 , 39 , 40 , 41 ]. In our review, only three studies used the AASM hypopnea definition (2007, 2016, 2017).…”

Association of Apnea vs Hypopnea Predominance With Pediatric Sleep Apnea Outcomes

“…Apneas are considered to be a more severe form of obstruction since they feature complete cessation of airflow. However, a recent retrospective review 23 in adult patients with OSA demonstrated that patients with apnea-predominant and hypopneapredominant OSA had similar comorbid medical conditions, including hypertension and cardiovascular disease. Another study 24 failed to demonstrate a difference in clinical outcomes among adult patients with OSA stratified according to apnea vs hypopnea predominance treated with mandibular advancement devices.…”