Cardiovascular Outcomes in Adults with Coronary Artery Disease and Obstructive Sleep Apnea with versus without Excessive Daytime Sleepiness in the RICCADSA Cinical Trial

Heart rate variability analysis in obstructive sleep apnea patients with daytime sleepiness

STUDY OBJECTIVES

Recent studies suggest that sleepy patients with obstructive sleep apnea (OSA) are at higher risk for incident cardiovascular disease. This study assessed cardiac autonomic function in sleepy versus non-sleepy patients with OSA using heart rate variability (HRV) analysis. We hypothesized that HRV profiles of sleepy patients would indicate higher cardiovascular risk.

METHODS

Electrocardiograms (ECG) derived from polysomnograms (PSG) collected by the Sydney Sleep Biobank were used to study HRV in groups of sleepy (ESS ≥ 10) and non-sleepy OSA patients (ESS < 10). HRV parameters were averaged across available ECG signals during N2 sleep.

RESULTS

A total of 421 patients were evaluated, with a mean age of 54 (14) years, body mass index of 33 (9) kg/m2, apnea-hypopnea index of 21 (28) events/h, and 66% male. The sleepy group consisted of 119 patients and the non-sleepy group 302 patients. Sleepy patients exhibited lower HRV values for: root mean square successive difference (RMSSD, p = 0.028), total power (TP, p = 0.031), absolute low frequency (LF, p = 0.045), and high-frequency (HF, p = 0.010) power compared to non-sleepy patients. Sleepy patients with moderate-to-severe OSA exhibited lower HRV values for: (RMSSD, p = 0.045; TP, p = 0.052), absolute LF (p = 0.051), and HF power (p = 0.025). There were no differences in other time and frequency domain HRV markers.

CONCLUSIONS

This study shows a trend toward parasympathetic withdrawal in sleepy OSA patients, particularly in moderate-to-severe cases, lending mechanistic support to the link between the sleepy phenotype and CVD risk in OSA.

Excessive daytime sleepiness is associated with increased residual cardiovascular risks among coronary artery disease patients with obstructive sleep apnea

OBJECTIVE

Excessive daytime sleepiness (EDS) frequently accompanies obstructive sleep apnea (OSA) and may increase cardiovascular risks. The majority of coronary artery disease (CAD) patients receive understandard treatments, it is not clear whether EDS is associated with increased residual cardiovascular risks in CAD patients with OSA.

METHOD

This study is a prospective cohort study that included 1215 consecutive CAD patients underwent overnight sleep study with a 3.7 year follow-up. Sleepiness was is determined by the Epworth Sleepiness Scale questionnaire. The primary endpoint was major adverse cardiovascular and cerebrovascular events (MACCE), including cardiovascular death, myocardial infarction, stroke, and heart failure. Kaplan-Meier model and Cox proportional hazards models were used to explore the relationship between residual cardiovascular risks and EDS.

RESULT

1027 cases were eventually enrolled, and a total of 129 patients experienced cardiovascular and cerebrovascular events. Participants with EDS had a higher risk of MACCE compared to those without EDS (17.02% vs. 9.58%, P = 0.005). The presence of EDS is associated with higher incidence of MACCE compared to non-EDS patients (HR 2.833; 95%CI:1.394-5.762; P < 0.001). EDS was significantly associated with increased incidence of MACCE in OSA patients (HR 1.765; 95%CI:1.276-2.543; P = 0.193), while there was no significant association between EDS and cardiovascular risks in non-OSA patients (HR 1.233; 95%CI: 0.893-2.755; P = 0.127).

CONCLUSIONS

The existence of EDS may lead to increased cardiovascular risks, EDS is associated with increased cardiovascular risks in CAD patients, especially in patients with OSA.

Long-term health outcomes for patients with obstructive sleep apnea: placing the Agency for Healthcare Research and Quality report in context-a multisociety commentary

This multisociety commentary critically examines the Agency for Healthcare Research and Quality (AHRQ) final report and systematic review on long-term health outcomes in obstructive sleep apnea. The AHRQ report was commissioned by the Centers for Medicare & Medicaid Services and particularly focused on the long-term patient-centered outcomes of continuous positive airway pressure, the variability of sleep-disordered breathing metrics, and the validity of these metrics as surrogate outcomes. This commentary raises concerns regarding the AHRQ report conclusions and their potential implications for policy decisions. A major concern expressed in this commentary is that the AHRQ report inadequately acknowledges the benefits of continuous positive airway pressure for several established, long-term clinically important outcomes including excessive sleepiness, motor vehicle accidents, and blood pressure. While acknowledging the limited evidence for the long-term benefits of continuous positive airway pressure treatment, especially cardiovascular outcomes, as summarized by the AHRQ report, this commentary reviews the limitations of recent randomized controlled trials and nonrandomized controlled studies and the challenges of conducting future randomized controlled trials. A research agenda to address these challenges is proposed including study designs that may include both high quality randomized controlled trials and nonrandomized controlled studies. This commentary concludes by highlighting implications for the safety and quality of life for the millions of people living with obstructive sleep apnea if the AHRQ report alone was used by payers to limit coverage for the treatment of obstructive sleep apnea while not considering the totality of available evidence.

CITATION

Patil SP, Billings ME, Bourjeily G, et al. Long-term health outcomes for patients with obstructive sleep apnea: placing the Agency for Healthcare Research and Quality report in context-a multisociety commentary. J Clin Sleep Med. 2024;20(1):135-149.

Obstructive sleep apnea severity and prevalent atrial fibrillation in a sleep clinic cohort with versus without excessive daytime sleepiness

BACKGROUND

Obstructive sleep apnea (OSA) is associated with atrial fibrillation (AF) in cardiac cohorts. Less is known regarding the magnitude of this association in a sleep clinic cohort with vs. without excessive daytime sleepiness (EDS).

OBJECTIVES

To explore the association of OSA severity with AF in a sleep clinic cohort stratified by EDS.

PATIENTS AND METHODS

All consecutive adults (n = 3814) admitted to the Skaraborg Hospital, Sweden between Jan 2005 and December 2011 were registered in a local database, and the follow-up ended in December 2018. OSA was defined as an apnea-hypopnea index (AHI) ≥5 events/h. Mild OSA was defined as AHI ≥5 & AHI<15 events/h; moderate OSA as AHI ≥15 & AHI<30 events/h; and severe OSA as AHI ≥30 events/h. EDS was defined as an Epworth Sleepiness Scale score ≥11. We conducted cross-sectional analyzes of the prevalent AF across the OSA severity categories and logistic regression analyzes stratified by EDS.

RESULTS

In all, 202 patients (5.3%) had AF at baseline, 1.6% in no-OSA, 3.9% in mild OSA, 5.2% in moderate OSA, and 7.6% in severe OSA, respectively (p < 0.001). The stratified analyzes revealed that patients with severe OSA without EDS had an increased risk for prevalent AF (OR 2.54, 95% CI 1.05-6.16; p = 0.039) independent of the confounding factors.

CONCLUSIONS

There was an independent dose-response relationship between OSA and prevalent AF among the non-sleepy phenotype in this sleep clinic cohort. Since adherence to OSA treatment is challenging in the absence of EDS, these patients may have increased risk for adverse cardiovascular outcomes.

Relationship between Symptom Profiles and Endotypes among Patients with Obstructive Sleep Apnea: A Latent Class Analysis

Rationale: Obstructive sleep apnea (OSA) is a heterogeneous syndrome with various endotypic traits and symptoms. A link among symptoms, endotypes, and disease prognosis has been proposed but remains unsupported by empirical data. Objectives: To link symptom profiles and endotypes by clustering endotypic traits estimated using polysomnographic signals. Methods: We recruited 509 patients with moderate to severe OSA from a single sleep center. Polysomnographic data were collected between May 2020 and January 2022. Endotypic traits, namely arousal threshold, upper airway collapsibility, loop gain, and upper airway muscle compensation, were retrieved using polysomnographic signals during non-rapid eye movement periods. We used latent class analysis to group participants into endotype clusters. Demographic and polysomnographic parameter differences were compared between clusters, and associations between endotype clusters and symptom profiles were examined using logistic regression analyses. Results: Three endotype clusters were identified, characterized by high collapsibility/loop gain, low arousal threshold, and low compensation, respectively. Patients in each cluster exhibited similar demographic characteristics, but those in the high collapsibility/loop gain cluster had the highest proportion of obesity and severe oxygen desaturation observed in polysomnographic studies. The low compensation cluster was characterized by fewer sleepy symptoms and exhibited a lower rate of diabetes mellitus. Compared with the excessively sleepy group, disturbed sleep symptoms were associated with the low arousal threshold cluster (odds ratio, 1.89; 95% confidence interval, 1.16-3.10). Excessively sleepy symptoms were associated with the high collapsibility/loop gain cluster (odds ratio, 2.16; 95% confidence interval, 1.39-3.37) compared with the minimally symptomatic group. Conclusions: Three pathological endotype clusters were identified among patients with moderate to severe OSA, each exhibiting distinct polysomnographic characteristics and clinical symptom profiles.

Unmasking Heterogeneity of Sleep Apnea

Sleep apnea is heterogeneous in multiple dimensions. There are different physiological risk factors that may have clinical relevance. However, assessing them is challenging. An approach to ascertain them using a simple model of ventilatory control has been proposed. It is based, however, on untenable assumptions. There are limited validation data and reproducibility is not stellar. There are also different symptom subtypes. They have been found in multiple population-based and clinical cohorts worldwide. Symptomatic benefit from therapy is most marked in the excessively sleepy subtype. This group may also be the group at increased CV risk from obstructive sleep apnea.

Five-year Transitions of Symptom Subtypes in Untreated Obstructive Sleep Apnea

Objectives

It is unknown if symptom subtypes of obstructive sleep apnea (OSA) transition over time and what clinical factors may predict transitions.

Methods

Data from 2,643 participants of the Sleep Heart Health Study with complete baseline and 5-year follow-up visits were analyzed. Latent Class Analysis on 14 symptoms at baseline and follow up determined symptom subtypes. Individuals without OSA (AHI<5) were incorporated as a known class at each time point. Multinomial logistic regression assessed the effect of age, sex, body mass index (BMI) and AHI on specific class transitions.

Results

The sample consisted of 1,408 women (53.8%) and mean (SD) age 62.4 (10.5) years. We identified four OSA symptom subtypes at both baseline and follow-up visits: minimally symptomatic, disturbed sleep, moderately sleepy and excessively sleepy . Nearly half (44.2%) of the sample transitioned to a different subtype from baseline to follow-up visits; transitions to moderately sleepy were the most common (77% of all transitions). A five-year older age was associated with a 6% increase in odds to transit from excessively sleepy to moderately sleepy [OR (95% CI) = 1.06 (1.02, 1.12)]. Women had 2.35 times higher odds (95% CI: 1.27, 3.27) to transition from moderately sleepy to minimal symptoms . A 5-unit increase in BMI was associated with 2.29 greater odds (95% CI: 1.19, 4.38) to transition from minimal symptoms to excessively sleepy .

Interpretation

While over half of the sample did not transition their subtype over 5 years, among those who did, the likelihood of transitioning between subtypes was significantly associated with a higher baseline age, higher baseline BMI and with women, but was not predicted by AHI.

Clinical Trials

Sleep Heart Health Study (SHHS) Data Coordinating Center, (SHHS) https://clinicaltrials.gov/ct2/show/NCT00005275 , NCT00005275.

Statement of significance

There is very little research assessing symptom progression and its contributions to clinical heterogeneity in OSA. In a large sample with untreated OSA, we grouped common OSA symptoms into subtypes and assessed if age, sex, or BMI predicted transitions between the subtypes over 5 years. Approximately half the sample transitioned to a different symptom subtype and improvements in symptom subtype presentation were common. Women and older individuals were more likely to transition to less severe subtypes, while increased BMI predicted transition to more severe subtype. Determining whether common symptoms like disturbed sleep or excessive daytime sleepiness occur early in the course of the disease or as a result of untreated OSA over an extended period can improve clinical decisions concerning diagnosis and treatment.