Clinical Features and Contributing Factors of Excessive Daytime Sleepiness in Chinese Obstructive Sleep Apnea Patients: The Role of Comorbid Symptoms and Polysomnographic Variables

Polysomnographic characteristics of excessive daytime sleepiness phenotypes in obstructive sleep apnea: results from the international sleep apnea global interdisciplinary consortium

STUDY OBJECTIVES

Excessive daytime sleepiness (EDS) is a major symptom of obstructive sleep apnea (OSA). Traditional polysomnographic (PSG) measures only partially explain EDS in OSA. This study analyzed traditional and novel PSG characteristics of two different measures of EDS among patients with OSA.

METHODS

Sleepiness was assessed using the Epworth Sleepiness Scale (>10 points defined as "risk of dozing") and a measure of general sleepiness (feeling sleepy ≥ 3 times/week defined as "feeling sleepy"). Four sleepiness phenotypes were identified: "non-sleepy," "risk of dozing only," "feeling sleepy only," and "both at risk of dozing and feeling sleepy."

RESULTS

Altogether, 2083 patients with OSA (69% male) with an apnea-hypopnea index (AHI) ≥ 5 events/hour were studied; 46% were "non-sleepy," 26% at "risk of dozing only," 7% were "feeling sleepy only," and 21% reported both. The two phenotypes at "risk of dozing" had higher AHI, more severe hypoxemia (as measured by oxygen desaturation index, minimum and average oxygen saturation [SpO2], time spent < 90% SpO2, and hypoxic impacts) and they spent less time awake, had shorter sleep latency, and higher heart rate response to arousals than "non-sleepy" and "feeling sleepy only" phenotypes. While statistically significant, effect sizes were small. Sleep stages, frequency of arousals, wake after sleep onset and limb movement did not differ between sleepiness phenotypes after adjusting for confounders.

CONCLUSIONS

In a large international group of patients with OSA, PSG characteristics were weakly associated with EDS. The physiological measures differed among individuals characterized as "risk of dozing" or "non-sleepy," while "feeling sleepy only" did not differ from "non-sleepy" individuals.

[Effect of Objective Daytime Sleepiness on Heart Rate Variability in Patients With Obstructive Sleep Apnea]

Objective

Excessive daytime sleepiness (EDS) is associated with cardiovascular events in patients with obstructive sleep apnea (OSA). Our study explored the correlation between objective daytime sleepiness assessed with daytime multiple sleep latency tests (MSLT) and heart rate variability (HRV) in OSA patients. The results may provide insight into possible mechanisms underlying increased risk of cardiovascular events in patients with OSA.

Methods

A retrospective analysis was conducted with the data of 139 patients with OSA and 35 patients with primary snoring. All subjects underwent polysomnography (PSG) and MSLT at West China Hospital between January 2019 and May 2022. We used mean sleep latency (MSL) to measure the severity of EDS and to categorize OSA patients into three groups, severe EDS, light EDS, and non-EDS, with MSL of less than 5 minutes, 5 to 10 minutes, and greater than 10 minutes as the respective defining criteria for classification. A comparison of sleep structure, clinical characteristics, and HRV parameters was performed in order to evaluate the difference between OSA subgroups with varying levels of objective EDS and the primary snoring group. In addition, we also analyzed the correlation between MSL and HRV parameters.

Results

Severe EDS patients had higher values of standard deviation of all N-N intervals (SDNN), total spectral power (TOT), and low-frequency power (LF) as compared to non-EDS patients, which was indicative of sympathetic stimulation ( P<0.05). Additionally, high-frequency power (HF) was also higher in severe EDS patients, which indicated decreased parasympathetic drive. A significantly positive correlation was found between MSL and the values of SDNN, TOT, LF, and HF in OSA patients.

Conclusion

OSA patients with objective EDS have elevated sympathetic drive and decreased parasympathetic drive. A positive correlation was found between this change in neural activity and the shortening of MSL.

Association between various breathing indexes during sleep and the Epworth Sleepiness Scale score in adults

Some breathing indexes during sleep, including the apnea-hypopnea index, oxygen desaturation index, and oxygen saturation during sleep, can be recorded by overnight polysomnography. We aimed to investigate the association of various breathing indexes during sleep with the Epworth Sleepiness Scale (ESS) score in adults. We retrospectively collected the clinical and overnight polysomnography data of 2829 adults aged 20 years or older from November 2011 to June 2017. The association of various breathing indexes during sleep and ESS score was analyzed using univariate and multivariate logistic regression analysis for all adults (20-91 years), and in each sex and of body mass index (<26 kg/m2 vs ≥26 kg/m2). The mean ESS score was 6.2 (standard deviation = 4.3; range = 0-24) for all adults. After adjustment for age, sex, many common diseases, and health-related habits, apnea-hypopnea index, oxygen desaturation index, percentage of oxygen saturation below 90% during sleep, and percentage of oxygen saturation below 85% during sleep were significantly positively associated with ESS score in all adults, whereas mean oxygen saturation during sleep, minimal oxygen saturation during sleep, and awake oxygen saturation during sleep were significantly negatively associated with ESS score in all adults. In subgroup analysis, we found that the association between breathing indexes during sleep and ESS score was similar in both sex, but was significant in subjects of body mass index ≥ 26 kg/m2. All breathing indexes during sleep had significant positive or negative correlation with ESS score in all adults, especially in obese subjects.

Correlates of excessive daytime sleepiness in obstructive sleep apnea: Results from the nationwide SESAR cohort including 34,684 patients

Excessive daytime sleepiness (EDS) is a hallmark symptom in obstructive sleep apnea (OSA). It is commonly eliminated by obstructive sleep apnea therapy and constitutes a major treatment indication. This study aimed to identify determinants of excessive daytime sleepiness by the Epworth Sleepiness Scale (ESS) scores in the large, representative national obstructive sleep apnea patient cohort of the Swedish Sleep Apnea Registry (SESAR, www.sesar.se). Data from 34,684 patients with obstructive sleep apnea recruited at 23 sites (33% females, mean age 55.7 ± 13.7 years, BMI 30.2 ± 6.3 kg/m² , AHI 29.1 ± 22.3, and ODI 24.9 ± 21.4 events/h) had a mean ESS score in the mild to moderate excessive daytime sleepiness range (9.7 ± 4.9). The proportion of patients with excessive daytime sleepiness was 41.4% in men and 44.6% in women. Independent predictors of excessive daytime sleepiness included gender, age, and hypoxic markers (high ODI and low mean saturation). Univariate and multivariate analyses were used to identify significant predictors for the ESS score and for excessive daytime sleepiness (ESS ≥10) amongst anthropometric factors, sleep apnea frequency (apnea-hypopnea index (AHI)), markers of intermittent hypoxia (oxygen desaturation index (ODI), mean saturation (mSaO₂ )), as well as prevalent comorbidities. Depression was associated with higher ESS scores and hypertension/atrial fibrillation with lower scores. The oxygen desaturation index provided a stronger predictor of excessive daytime sleepiness than the apnea-hypopnea index. The severity of obstructive sleep apnea, captured as the apnea-hypopnea index, was only weakly associated with daytime sleepiness in this representative obstructive sleep apnea patient cohort. Age had different effects in men and women.The impact of obstructive sleep apnea in a wider patient related perspective needs to be determined after the inclusion of factors other than the apnea-hypopnea index.

Impact of common diseases and habits on daytime sleepiness in adults

We aimed to investigate the impact of common diseases and habits on daytime sleepiness in adults. We retrospectively collected the clinical and overnight polysomnographic data of 2829 adults. The impact of common diseases and habits on the Epworth Sleepiness Scale (ESS) score was analyzed by univariate and multivariate linear regression analyses. The mean ESS score was 6.2 (standard deviation = 4.3; range = 0-24) for all adults. Multivariate linear regression analysis showed that dyslipidemia, acute myocardial infarction (AMI), liver cirrhosis, alcohol drinking, and tea consumption had a significantly positive association with ESS score for all adults after adjusting for age, sex, body mass index, apnea-hypopnea index, sleep efficiency, percentage of sleep N3 stage, and depression. Subgroup analysis by sex showed that AMI, liver cirrhosis, alcohol drinking, and tea consumption had significantly positive association with ESS scores in males, whereas only dyslipidemia had significantly positive association with ESS scores in females. Subgroup analysis by age showed that alcohol drinking had a significantly positive association with ESS scores in young adults. AMI had a significantly positive association with ESS scores, but chronic kidney disease had a significantly negative association with ESS scores in middle-aged adults. Furthermore, dyslipidemia, chronic kidney disease, and cancers had a significantly positive association with ESS scores in older adults. Dyslipidemia, AMI, liver cirrhosis, alcohol drinking, and tea consumption had a significantly positive association with daytime sleepiness in adults but differed by sex and age.

Profile of subjective-objective sleep discrepancy in patients with insomnia and sleep apnea

STUDY OBJECTIVES

Although subjective-objective sleep discrepancy has long been observed in patients with insomnia, the profiles of this discrepancy are poorly understood. Further, sleep discrepancy in insomnia with sleep comorbidities remains underexplored. We sought to better characterize sleep discrepancy among patient groups with and without insomnia and comorbid conditions such as obstructive sleep apnea (OSA).

METHODS

Using data from the Sleep Heart Health Study, we conducted a secondary analysis describing (1) the profile of self-reported and objective sleep measures in patients with insomnia (IS group; n = 73) and comorbid OSA (IS + OSA group; n = 143), compared with individuals with OSA only (OSA group; n = 296) and normal sleep control patients (NSC group; n = 126); (2) the comparative magnitude of sleep misperception between these 4 groups; and (3) the self-reported quality of life (QOL) in the 4 groups.

RESULTS

Subjective-objective sleep discrepancy existed in all 4 groups, including the NSC group. Controlling for age, sex, mental health conditions, sleep apnea severity, and objectively measured sleep time, the presence of self-reported insomnia had the strongest association with sleep discrepancy. In patients with insomnia, sleep onset latency was overestimated (7.8 ± 36.8 min in the IS group; P < .001 when compared to the NSC and OSA groups), with the largest differences seen in the comorbid IS + OSA group (15.0 ± 56.8 min). Insomnia conferred the most negative impact on QOL, with the combined IS + OSA group reporting the lowest QOL.

CONCLUSIONS

Self-reported insomnia is associated with sleep discrepancy and negative QOL. Those with comorbid OSA reported the greatest sleep discrepancy and the lowest QOL. Future research is warranted to further understand individual profiles of misperception and insomnia phenotypes.

CITATION

Ma Y, Goldstein MR, Davis RB, Yeh GY. Profile of subjective-objective sleep discrepancy in patients with insomnia and sleep apnea. J Clin Sleep Med. 2021;17(11):2155-2163.

Current Management of Residual Excessive Daytime Sleepiness Due to Obstructive Sleep Apnea: Insights for Optimizing Patient Outcomes

Although excessive daytime sleepiness (EDS) attributable to obstructive sleep apnea (OSA) can be resolved by consistent usage of and effective treatment (often with the use of continuous positive airway pressure therapy), 12–58% of patients report residual EDS (REDS). While REDS is difficult to treat, a proportion of cases are possibly due to reversible issues, and wake-promoting medications can prove useful for the remaining cases. Given the challenges associated with effective management of REDS and its relationship to multiple comorbidities, multidisciplinary management of patients with REDS is often recommended. Here we aim to bridge the knowledge gap on the burden, risk factors, prevalence, and potential pathophysiologic mechanisms of REDS in patients with OSA after first-line treatment. The roles of primary care physicians and sleep specialists, as well as the importance of the use of objective assessment tools for the evaluation of REDS and the effective management of comorbidities, are discussed. An update of approved treatments and emerging candidate treatments is also presented.

Periodic limb movements in patients with obstructive sleep apnea syndrome

The aim of the study was to assess the factors associated with periodic limb movements during sleep (PLMS) among obstructive sleep apnea syndrome (OSAS) patients and identify the role of PLMS in patients with OSAS. 303 adult patients with OSAS were included in the study. All patients completed physical examination, Epworth sleepiness scale (ESS), and polysomnography. Diagnosis of PLMS was made if the periodic leg movements index (PLMI) was ≥ 15. Chi-square test, ANOVA, univariate and multivariate logistic regression analyses were conducted to identify factors associated with PLMS among OSAS patients. Statistical analyses were performed with SPSS 26.0 for mac. Statistically significant difference was considered if P value < 0 .05. Among the 303 adult patients with OSAS, 98 patients had significant PLMS and the other 205 had no significant PLMS. Compared with OSAS patients without PLMS, OSAS patient with PLMS were older, had shorter REM duration and greater apnea–hypopnea index (AHI) (P < 0.05). The study suggests that PLMS is a matter of concern among patients with OSAS. A better understanding of the role of PLMS among OSAS patients could be useful in better recognition, intervention and treatment of OSAS.

Impact of bariatric surgery on obstructive sleep apnea severity and continuous positive airway pressure therapy compliance-prospective observational study

To evaluate association between bariatric surgery and changes in obstructive sleep apnea (OSA) severity and sleep architecture was as well as to asses continuous positive airway pressure (CPAP) effectiveness and compliance. We enrolled patients undergoing bariatric surgery. Polysomnography was performed in each patient preoperatively and 12 months after the procedure in a subgroup of patients diagnosed with OSA. STOP-BANG, Epworth Sleepiness Scale (ESS) and Berlin questionnaire scores were obtained pre- and postoperatively. CPAP compliance data was recorded during follow-up hospitalization. Among 44 patients with median age of 49.5 years, predominantly women (68.2%) pre- and postoperative polysomnography was performed. We observed significant improvement in STOP-BANG (6.0 vs. 3.0, p < 0.001) and ESS (12.0 vs. 5.0, p < 0.001) scores, apnea–hypopnea index (44.9 vs. 29.2, p < 0.001), oxygen desaturation index (43.6 vs. 18.3, p < 0.001) and sleep architecture parameters. CPAP compliance was poor with a median percentage of days with CPAP use accounting to 49.3%. Bariatric surgery is associated with a significant decrease in the number of sleep-related respiratory disturbances, as well as improvement of sleep efficiency. Postoperative CPAP therapy compliance was poor despite low rate of OSA resolution. This study suggests that patients with OSA undergoing bariatric surgery require postoperative reassessment.

Prevalence and factors correlated with hypertension secondary from obstructive sleep apnea

Background

In 2003, the JNC 7 reported obstructive sleep apnea (OSA) as a cause of secondary hypertension. The prevalence of OSA in hypertension ranges from 30-80%. There are limited data on the prevalence and risk factors of OSA in hypertensive patients. This study thus aimed to evaluate prevalence and clinical predictors of obstructive sleep apnea (OSA) in these patients.

Methods

This was a cross-sectional study and conducted at the hypertension clinic at Khon Kaen University’s Srinagarind Hospital, Thailand. We enrolled patients with hypertension treated at the clinic. OSA was defined as apnea-hypopnea index of 5 events/hour or over according to cardiopulmonary monitoring. Patients whose hypertension was due to any other causes were excluded. The prevalence of OSA was calculated and risk factors for OSA were analyzed using multivariate logistic regression.

Results

There were 726 hypertensive patients treated at the clinic. Out of those, 253 (34.8%) were randomly studied and categorized as either non-OSA (147 patients, 58.1%) or OSA (106 patients, 41.9%). There were four independent factors associated with OSA-induced hypertension: age, sex, history of snoring, and history of headache. Headache had an adjusted odds ratio (95% confidence interval) of 3.564 (95% confidence interval of 1.510, 8.411).

Conclusion

Age, male sex, history of snoring, and headache were independent predictors of hypertension caused by OSA.

Smoking history and its relationship with comorbidities in patients with obstructive sleep apnea

INTRODUCTION

Current knowledge on the correlation between smoking and comorbidities associated with obstructive sleep apnea (OSA) is limited. This study evaluated the smoking history of OSA patients and analyzed the association between smoking and OSA comorbidities.

METHODS

Retrospective analysis was performed in newly diagnosed OSA patients in our hospital, a tertiary medical center, from January 2016 to December 2019. In all, 1021 patients were enrolled and divided into two groups, non-smokers (n=796) and current/former smokers (n=225), in order to compare their clinical manifestations and polysomnographic results and to analyze the association between smoking and comorbidities.

RESULTS

Compared with the non-smokers, the current/former smokers had higher Epworth sleepiness scale (ESS) scores (9.3 ± 4.0 vs 8.5 ± 5.1; p<0.05), longer sleep latency (SL) [20.5 (12.3-39.3) vs 18.5 (10.0-34.0) minutes; p<0.05], and a lower nocturnal mean oxygen saturation (91.8 ± 3.6% vs 92.8 ± 3.4%; p<0.001). There was no significant difference in the apnea-hypopnea index (AHI) between the two groups. OSA patients with a history of smoking had significantly increased risk of hypertension (OR=2.09; 95% CI: 1.46- 3.01), chronic obstructive pulmonary disease (COPD) (OR=9.80; 95% CI: 4.73-20.33), gastroesophageal reflux disease (GERD) (OR=1.97; 95% CI: 1.19-3.27), and chronic pharyngitis (OR=1.83; 95% CI: 1.32-2.54).

CONCLUSIONS

No significant association was found between previous smoking history and current OSA severity. OSA patients with a history of smoking had an increased risk of hypertension, COPD, GERD, and chronic pharyngitis.

Smoking and sleep apnea duration mediated the sex difference in daytime sleepiness in OSA patients

PURPOSE

Daytime sleepiness is a common symptom of obstructive sleep apnea (OSA) and is more common in men, but the underlying mechanism remains unclear. The aim of this study was to assess whether or not sex differences in daytime sleepiness persisted after controlling for age and OSA severity and to explore the factors contributing to daytime sleepiness in patients with OSA.

METHODS

A total of 104 pairs of patients with OSA, matched by age and apnea-hypopnea index (AHI), were enrolled in this retrospective study. Demographic data were collected; daytime sleepiness was measured by the Epworth Sleepiness Scale (ESS); and polysomnography (PSG) was performed on each participant. These measurements were compared between sexes, and the factors affecting daytime sleepiness were explored with correlation and multivariate linear regression analyses.

RESULTS

Men had significantly higher ESS scores (p = 0.021) than women. Regarding demographics, BMI, neck/height ratio, and proportion of habitual smoking and alcohol intake were significantly higher in men. Regarding PSG findings, men had more rapid eye movement sleep, a longer mean apnea-hypopnea duration, and a longer mean apnea duration (MAD). Regression analysis showed that two sex-associated variables, habitual smoking (β = 0.189, p = 0.006) and MAD (β = 0.154, p = 0.024), had the strongest association with ESS scores. Further analysis revealed that MAD was significantly influenced by apnea index (β = 0.306, p < 0.001) and sex (β = - 0.193, p = 0.003).

CONCLUSION

The sex difference in daytime sleepiness persists in patients with OSA, even after matching AHI and age. The difference is mediated by sex-specific smoking habits and sex differences in apnea duration.