Severity of Desaturations Reflects OSA-Related Daytime Sleepiness Better Than AHI

Abstract

Study Objectives: The aim was to investigate how the severity of apneas, hypopneas, and related desaturations is associated with obstructive sleep apnea (OSA)-related daytime sleepiness. Methods: Multiple Sleep Latency Tests and polysomnographic recordings of 362 patients with OSA were retrospectively analyzed and novel diagnostic parameters (eg, obstruction severity and desaturation severity), incorporating severity of apneas, hypopneas, and desaturations, were computed. Conventional statistical analysis and multivariate analyses were utilized to investigate connection of apnea-hypopnea index (AHI), oxygen desaturation index (ODI), conventional hypoxemia parameters, and novel diagnostic parameters with mean daytime sleep latency (MSL). Results: In the whole population, 10% increase in values of desaturation severity (risk ratio = 2.01, P <.001), obstruction severity (risk ratio = 2.18, P <.001) and time below 90% saturation (t 90% ) (risk ratio = 2.05, P < .001) induced significantly higher risk of having mean daytime sleep latency ≤ 5 minutes compared to 10% increase in AHI (risk ratio = 1.63, P <.05). In severe OSA, desaturation severity had significantly (P <.02) stronger negative correlation (ρ = −.489, P <.001) with mean daytime sleep latency compared to AHI (ρ = −.402, P < 0.001) and ODI (ρ = −.393, P < .001). Based on general regression model, desaturation severity and male sex were the most significant factors predicting daytime sleep latency. Conclusions: Severity of sleep-related breathing cessations and desaturations is a stronger contributor to daytime sleepiness than AHI or ODI and therefore should be included in the diagnostics and severity assessment of OSA.

Severe desaturations increase psychomotor vigilance task-based median reaction time and number of lapses in obstructive sleep apnoea patients

“…AHI, ODI and AI) are not. This finding is supported by our previous study [7], showing that OSA-related objective daytime sleepiness is more strongly associated with the severity of individual desaturations than the number of apneas and hypopneas. Furthermore, these results correspond with previous studies [8,9,[18][19][20][21][22], by showing that conventional AHI-based assessments of OSA have little connection to poor PVT performance.…”

“…Similar findings have also been reported in other studies investigating cognitive impairment in OSA patients and healthy individuals[9,19,20,22,35]. Moreover, in our recent studies, we reported that a larger desaturation area is a significant predictor of objective daytime sleepiness and the most detrimental health consequences of OSA[7,29,31]. Together with these findings, this study highlights the urgent need to develop the diagnostics of OSA beyond the AHI.…”

“…Furthermore, these results correspond with previous studies [8,9,[18][19][20][21][22], by showing that conventional AHI-based assessments of OSA have little connection to poor PVT performance. These findings highlight, together with recent studies [7,24,29,31], the clinical importance of a more detailed analysis of PSG recordings when assessing OSA severity, symptoms and daytime functioning. As the presented novel parameters are based on routine manual scoring of PSG, they can be easily implemented to clinics without any extra work required of technical or medical staff [32].…”

“…Sforza et al [18] showed that the number of lapses correlated moderately with the minimum and mean blood oxygen saturation (r = -0.454 and -0.421, respectively), but this was achieved using an atypically long reaction time limit of 1000 ms. In addition, we recently demonstrated that longer and deeper desaturations, regardless of the AHI, significantly increases the risk of objectively measured excessive daytime sleepiness [7].…”

“…Obstructive sleep apnea (OSA) is one of the most prevalent sleep disorders, affecting at least 20% of the adult population in Western countries [2][3][4]. OSA is attributed to daytime symptoms of shortened daytime sleep latencies as well as chronic fatigue and sleepiness [5][6][7]. Furthermore, OSA is related to poor neurocognitive performance and inability to sustain attention [8][9][10].…”