Clinical polysomnographic methods for estimating pharyngeal collapsibility in obstructive sleep apnea

Effect of norepinephrine reuptake inhibitors combined with antimuscarinic agents vs monotherapy for OSA: a systematic review and meta-analysis

STUDY OBJECTIVES

Randomized controlled trials have shown that combining norepinephrine reuptake inhibitors and antimuscarinics can ameliorate the severity of obstructive sleep apnea. This article explores whether the effectiveness and safety of combining norepinephrine reuptake inhibitors with antimuscarinic agents surpass monotherapy for treating obstructive sleep apnea.

METHODS

We searched randomized controlled trials including adult patients with obstructive sleep apnea who received combination therapy and monotherapy in 8 databases from inception until April 5, 2023 and evaluated the studies' quality and conducted a meta-analysis and systematic review. The primary outcome was the apnea-hypopnea index. Secondary outcome measures included loop gain, hypoxic burden, oxygen desaturation index, and ventilation at low ventilatory drive, among other indicators. We assessed the quality of the studies using Cochrane Methods criteria.

RESULTS

We identified 4 randomized controlled trials for systematic review and 2 for meta-analysis. The results of the meta-analysis showed that norepinephrine reuptake inhibitors combined with antimuscarinic agents in patients with obstructive sleep apnea prolonged total sleep time by a mean of 28.20 minutes [95% confidence interval (5.78, 50.61), P = .01] and increased sleep efficiency by 4.73% [95% confidence interval (0.50, 8.97), P = .03] compared with norepinephrine reuptake inhibitors alone. Other indices and adverse events were of no statistical significance. The systematic reviews revealed that norepinephrine reuptake inhibitors combined with antimuscarinics may be superior to monotherapy in improving apnea-hypopnea index and endotypic traits.

CONCLUSIONS

This evaluation demonstrated the potential advantages of combining norepinephrine reuptake inhibitors plus antimuscarinics for treating OSA compared with norepinephrine reuptake inhibitors alone and revealed no statistically significant difference in drug safety.

CITATION

Wang J, Ye Y, Shang Z, et al. Effect of norepinephrine reuptake inhibitors combined with antimuscarinic agents vs monotherapy for OSA: a systematic review and meta-analysis. J Clin Sleep Med. 2024;20(8):1363-1372.

Effect of obesity on sleep apnea pathogenesis differs in women versus men: multiple mediation analyses in the retrospective SNOOzzzE cohort

There are multiple mechanisms underlying obstructive sleep apnea (OSA) development. However, how classic OSA risk factors such as body mass index (BMI) and sex portend to OSA development has not been fully described. Thus we sought to evaluate how obesity leads to OSA and assess how these mechanisms differ between men and women. The San Diego Multi-Outcome OSA Endophenotype (SNOOzzzE) cohort includes 3,319 consecutive adults who underwent a clinical in-laboratory polysomnography at the University of California, San Diego, sleep clinic between January 2017 and December 2019. Using routine polysomnography signals, we determined OSA endotypes. We then performed mediation analyses stratified by sex to determine how BMI influenced the apnea-hypopnea index (AHI) using OSA pathophysiological traits as mediators, adjusting for age, race, and ethnicity. We included 2,146 patients of whom 919 (43%) were women and 1,227 (57%) were obese [body mass index (BMI) > 30 kg/m2]. BMI was significantly associated with AHI in both women and men. In men, the adjusted effect of BMI on AHI was partially mediated by a reduction in upper airway stiffness (βstandardized = 0.124), a reduction in circulatory delay (βstandardized = 0.063), and an increase in arousal threshold (βstandardized = 0.029; Pboot-strapped,all < 0.05). In women, the adjusted effect of BMI on AHI was partially mediated by a reduction in upper airway stiffness (βstandardized = 0.05) and circulatory delay (βstandardized = 0.037; Pboot-strapped,all < 0.05). BMI-related OSA pathogenesis differs by sex. An increase in upper airway collapsibility is consistent with prior studies. A reduction in circulatory delay may lead to shorter and thus more events per hour (higher AHI), while the relationship between arousal threshold and OSA is likely complex.NEW & NOTEWORTHY Our data provide important insights into obesity-related obstructive sleep apnea (OSA) pathogenesis, thereby validating, and extending, prior research findings. This is the largest sample size study to examine the relationships between obesity and gender on OSA pathogenesis. The influence of obesity on sleep apnea severity is mediated by different mechanistic traits (endotypes).

Obstructive sleep apnea heterogeneity and autonomic function: a role for heart rate variability in therapy selection and efficacy monitoring

Obstructive sleep apnea is a highly prevalent sleep-related breathing disorder, resulting in a disturbed breathing pattern, changes in blood gases, abnormal autonomic regulation, metabolic fluctuation, poor neurocognitive performance, and increased cardiovascular risk. With broad inter-individual differences recognised in risk factors, clinical symptoms, gene expression, physiological characteristics, and health outcomes, various obstructive sleep apnea subtypes have been identified. Therapeutic efficacy and its impact on outcomes, particularly for cardiovascular consequences, may also vary depending on these features in obstructive sleep apnea. A number of interventions such as positive airway pressure therapies, oral appliance, surgical treatment, and pharmaceutical options are available in clinical practice. Selecting an effective obstructive sleep apnea treatment and therapy is a challenging medical decision due to obstructive sleep apnea heterogeneity and numerous treatment modalities. Thus, an objective marker for clinical evaluation is warranted to estimate the treatment response in patients with obstructive sleep apnea. Currently, while the Apnea-Hypopnea Index is used for severity assessment of obstructive sleep apnea and still considered a major guide to diagnosis and managements of obstructive sleep apnea, the Apnea-Hypopnea Index is not a robust marker of symptoms, function, or outcome improvement. Abnormal cardiac autonomic modulation can provide additional insight to better understand obstructive sleep apnea phenotyping. Heart rate variability is a reliable neurocardiac tool to assess altered autonomic function and can also provide cardiovascular information in obstructive sleep apnea. Beyond the Apnea-Hypopnea Index, this review aims to discuss the role of heart rate variability as an indicator and predictor of therapeutic efficacy to different modalities in order to optimise tailored treatment for obstructive sleep apnea.

Annual review of selected scientific literature: A report of the Committee on Scientific Investigation of the American Academy of Restorative Dentistry

The Scientific Investigation Committee of the American Academy of Restorative Dentistry offers this review of the 2022 dental literature to briefly touch on several topics of interest to modern restorative dentistry. Each committee member brings discipline-specific expertise in their subject areas that include (in order of the appearance in this report): prosthodontics; periodontics, alveolar bone, and peri-implant tissues; dental materials and therapeutics; occlusion and temporomandibular disorders; sleep-related breathing disorders; oral medicine and oral and maxillofacial surgery; and dental caries and cariology. The authors focused their efforts on reporting information likely to influence the daily dental treatment decisions of the reader with an emphasis on innovations, new materials and processes, and future trends in dentistry. With the tremendous volume of literature published daily in dentistry and related disciplines, this review cannot be comprehensive. Instead, its purpose is to update interested readers and provide valuable resource material for those willing to subsequently pursue greater detail on their own. Our intent remains to assist colleagues in navigating the tremendous volume of newly minted information produced annually. Finally, we hope that readers find this work helpful in managing patients.

Sleep Apnea Physiological Burdens and Cardiovascular Morbidity and Mortality

Rationale: Obstructive sleep apnea is characterized by frequent reductions in ventilation, leading to oxygen desaturations and/or arousals. Objectives: In this study, association of hypoxic burden with incident cardiovascular disease (CVD) was examined and compared with that of "ventilatory burden" and "arousal burden." Finally, we assessed the extent to which the ventilatory burden, visceral obesity, and lung function explain variations in hypoxic burden. Methods: Hypoxic, ventilatory, and arousal burdens were measured from baseline polysomnograms in the Multi-Ethnic Study of Atherosclerosis (MESA) and the Osteoporotic Fractures in Men (MrOS) studies. Ventilatory burden was defined as event-specific area under ventilation signal (mean normalized, area under the mean), and arousal burden was defined as the normalized cumulative duration of all arousals. The adjusted hazard ratios for incident CVD and mortality were calculated. Exploratory analyses quantified contributions to hypoxic burden of ventilatory burden, baseline oxygen saturation as measured by pulse oximetry, visceral obesity, and spirometry parameters. Measurements and Main Results: Hypoxic and ventilatory burdens were significantly associated with incident CVD (adjusted hazard ratio [95% confidence interval] per 1 SD increase in hypoxic burden: MESA, 1.45 [1.14, 1.84]; MrOS, 1.13 [1.02, 1.26]; ventilatory burden: MESA, 1.38 [1.11, 1.72]; MrOS, 1.12 [1.01, 1.25]), whereas arousal burden was not. Similar associations with mortality were also observed. Finally, 78% of variation in hypoxic burden was explained by ventilatory burden, whereas other factors explained only <2% of variation. Conclusions: Hypoxic and ventilatory burden predicted CVD morbidity and mortality in two population-based studies. Hypoxic burden is minimally affected by measures of adiposity and captures the risk attributable to ventilatory burden of obstructive sleep apnea rather than a tendency to desaturate.

Sleep and Breathing Conference highlights 2023: a summary by ERS Assembly 4

This paper presents some of the highlights of the Sleep and Breathing Conference 2023 https://bit.ly/46MxJml.

The role of oral appliance therapy in obstructive sleep apnoea

There is now widespread recognition within the world of sleep medicine of the increasing importance of dental sleep medicine and, in particular, the role of oral appliance therapy (OAT) in the management of adults with obstructive sleep apnoea (OSA). For the purpose of this review, the term OAT refers to a custom-made intra-oral appliance, which acts to posture the mandible in a forward and downward direction, away from its natural resting position. Whilst nasally applied continuous positive airway pressure remains the "gold standard" in nonsurgical OSA management, OAT remains the recognised alternative treatment.This review of OAT aims to provide an evidence-based update on our current understanding of their mode of action, exploring the potential anatomical and physiological impact of their use in preventing collapse of the upper airway; the current clinical practice guidelines, including the recently published National Institute of Clinical Excellence 2021 guidance, in conjunction with the American Academy of Sleep Medicine and American Academy of Dental Sleep Medicine; optimal design features, comparing the role of custom-made versus noncustom OAT devices and the importance of titration in achieving a dose-dependent effect; patient predictors, preference and adherence to OAT; its impact on a range of both patient- and clinician-centred health outcomes, with a comparison with CPAP; the limitations and side-effects of providing OAT; and, finally, a look at future considerations to help optimise the delivery and outcomes of OAT.

Effects of atomoxetine plus a hypnotic on obstructive sleep apnea severity in patients with a moderately collapsible pharyngeal airway

STUDY OBJECTIVES

Pharmacotherapy for obstructive sleep apnea (OSA) regained consideration after the discovery that atomoxetine and oxybutynin greatly reduced OSA severity. However, atomoxetine and oxybutynin reduced the arousal threshold and may therefore be poorly tolerated in patients with OSA and disturbed sleep. As a result, we tested the combination of atomoxetine plus 2 hypnotics in patients with OSA. The effects of atomoxetine plus: (1) trazodone (Ato-Trazo) and (2) lemborexant vs placebo on apnea-hypopnea index, hypoxic burden, arousal threshold, and total sleep time were assessed. Drug safety was also ascertained, together with the effect of the combinations on other OSA traits, self-reported sleep quality, and next-day alertness.

METHODS

Following a baseline study, 15 patients with mild-to-severe OSA with moderate upper airway collapsibility were administered Ato-Trazo, atomoxetine and lemborexant, and matching placebo according to a double-blind, randomized, crossover design. Apnea-hypopnea index and other objective outcomes were calculated from 3 clinical, in-laboratory polysomnograms.

RESULTS

Ato-Trazo significantly reduced apnea-hypopnea index from a median [interquartile range] of 18.2 [11.8 to 31.3] on placebo to 7.4 [5.4 to 16.1] events/h, P = .024, and hypoxic burden from 46.3 [25.1 to 88.3] on placebo to 18.7 [14.9 to 43.5], P = .003. This effect was likely driven by an increase in polysomnography-estimated pharyngeal muscle activity during the events (P = .029). Atomoxetine and lemborexant had smaller statistically insignificant effects. Contrary to atomoxetine and oxybutynin, Ato-Trazo and atomoxetine and lemborexant did not reduce the arousal threshold. Both combinations had no effect on total sleep time but worsened self-reported sleep quality.

CONCLUSIONS

Ato-Trazo has the potential to become a useful drug combination, however, longer trials are needed to determine the best dosage and the subgroup of patients who may benefit most from this combination.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Crossover Trial of AD182 and AD504 in Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/ct2/show/NCT04645524; Identifier: NCT04645524.

CITATION

Corser B, Eves E, Warren-McCormick J, Rucosky G. Effects of atomoxetine plus a hypnotic on obstructive sleep apnea severity in patients with a moderately collapsible pharyngeal airway. J Clin Sleep Med. 2023;19(6):1035-1042.

Night-to-Night Variability of Polysomnography-Derived Physiologic Endotypic Traits in Patients With Moderate to Severe OSA

BACKGROUND

Emerging data suggest that determination of physiologic endotypic traits (eg, loop gain) may enable precision medicine in OSA.

RESEARCH QUESTION

Does a single-night assessment of polysomnography-derived endotypic traits provide reliable estimates in moderate to severe OSA?

STUDY DESIGN AND METHODS

Two consecutive in-lab polysomnography tests from a clinical trial (n = 67; male, 69%; mean ± SD age, 61 ± 10 years; apnea-hypopnea index [AHI] 53 ± 22 events/h) were used for the reliability analysis. Endotypic traits, reflecting upper airway collapsibility (ventilation at eupneic drive [Vpassive]), upper airway dilator muscle tone (ventilation at the arousal threshold [Vactive]), loop gain (stability of ventilatory control, LG1), and arousal threshold (ArTh) were determined. Reliability was expressed as an intraclass correlation coefficient (ICC). Minimal detectable differences (MDDs) were computed to provide an estimate of maximum spontaneous variability. Further assessment across four repeated polysomnography tests was performed in a subcohort (n = 22).

RESULTS

Reliability of endotypic traits between the two consecutive nights was moderate to good (ICC: Vpassive = 0.82, Vactive = 0.76, LG1 = 0.72, ArTh = 0.83). Variability in AHI, but not in body position or in sleep stages, was associated with fluctuations in Vpassive and Vactive (r = -0.49 and r = -0.41, respectively; P < .001 for both). MDDs for single-night assessments were: Vpassive = 22, Vactive = 34, LG1 = 0.17, and ArTh = 21. Multiple assessments (mean of two nights, n = 22) further reduced MDDs by approximately 20% to 30%.

INTERPRETATION

Endotypic trait analysis using a single standard polysomnography shows acceptable reliability and reproducibility in patients with moderate to severe OSA. The reported MDDs of endotypic traits may facilitate the quantification of relevant changes and may guide future evaluation of interventions in OSA.

Determinants of awake oropharyngeal volume reduction between sitting and supine positions in children evaluated for snoring

Pharyngeal collapsibility is a major determinant of obstructive sleep apnea (OSA) pathophysiology, but its anatomical predictors in children are largely unknown. We hypothesised that anatomical (tonsillar hypertrophy, narrow palate, nasal obstruction, dental/skeletal malocclusion, obesity) and OSA-related (apnea-hypopnea index, AHI) parameters could be related to a measure of awake pharyngeal collapsibility. We performed acoustic pharyngometry in children evaluated for suspected OSA, allowing us to measure the reduction of oropharyngeal volume in supine versus sitting position normalised for the volume in supine position (ΔV%), a measure of pharyngeal collapsibility. In addition to polysomnography and a clinical examination (anatomical parameters), acoustic rhinometry was used to assess nasal obstruction. A total of 188 snoring children were included, 118 (63%) of whom were obese and 74 (39%) of whom had moderate to severe OSA (AHI ≥5/h). The median (25th-75th percentiles) ΔV% in the whole population was 20.1% (4.7; 43.3). ΔV% was independently and positively associated with AHI (p = 0.023), z-score of BMI (p = 0.001), tonsillar hypertrophy (p = 0.007), narrow palate (p = 0.035), and African (p < 0.001) ancestry. By contrast, ΔV% was not modified by dental or skeletal malocclusion, Friedman palate position class or nasopharyngeal obstruction. Tonsillar hypertrophy, obesity, narrow palate and African ancestry are independently associated with an increase in pharyngeal collapsibility in snoring children, thus increasing the risk of OSA. Increased pharyngeal compliance in African children may explain the increased risk of residual OSA after adenotonsillectomy observed in this population.

Pathophysiology Underlying Demographic and Obesity Determinants of Sleep Apnea Severity

Rationale: Sleep apnea is the manifestation of key endotypic traits, including greater pharyngeal collapsibility, reduced dilator muscle compensation, and elevated chemoreflex loop gain. Objectives: We investigated how endotypic traits vary with obesity, age, sex, and race/ethnicity to influence sleep apnea disease severity (apnea-hypopnea index [AHI]). Methods: Endotypic traits were estimated from polysomnography in a diverse community-based cohort study (Multi-Ethnic Study of Atherosclerosis, N = 1,971; age range, 54-93 yr). Regression models assessed associations between each exposure (continuous variables per 2 standard deviations [SDs]) and endotypic traits (per SD) or AHI (events/h), independent of other exposures. Generalizability was assessed in two independent cohorts. Results: Greater AHI was associated with obesity (+19 events/h per 11 kg/m2 [2 SD]), male sex (+13 events/h vs. female), older age (+7 events/h per 20 yr), and Chinese ancestry (+5 events/h vs. White, obesity adjusted). Obesity-related increase in AHI was best explained by elevated collapsibility (+0.40 SD) and greater loop gain (+0.38 SD; percentage mediated, 26% [95% confidence interval (CI), 20-32%]). Male-related increase in AHI was explained by elevated collapsibility (+0.86 SD) and reduced compensation (-0.40 SD; percentage mediated, 57% [95% CI, 50-66%]). Age-related AHI increase was explained by elevated collapsibility (+0.37 SD) and greater loop gain (+0.15 SD; percentage mediated, 48% [95% CI, 34-63%]). Increased AHI with Chinese ancestry was explained by collapsibility (+0.57 SD; percentage mediated, 87% [95% CI, 57-100]). Black race was associated with reduced collapsibility (-0.30 SD) and elevated loop gain (+0.29 SD). Similar patterns were observed in the other cohorts. Conclusions: Different subgroups exhibit different underlying pathophysiological pathways to sleep apnea, highlighting the variability in mechanisms that could be targeted for intervention.

The norepinephrine reuptake inhibitor reboxetine alone reduces obstructive sleep apnea severity: a double-blind, placebo-controlled, randomized crossover trial

STUDY OBJECTIVES

Recent findings indicate that noradrenergic and muscarinic processes are crucial for pharyngeal muscle control during sleep. However, to date, reductions in obstructive sleep apnea (OSA) severity have only been detected when noradrenergic agents are combined with an antimuscarinic. Accordingly, this study aimed to determine if reboxetine alone and combined with oxybutynin reduces OSA severity. The pathophysiological mechanisms underpinning the effects of these agents were also investigated via endotyping analysis.

METHODS

Sixteen people (6 women) with OSA completed 3 polysomnograms (∼1-week washout) according to a double-blind, placebo-controlled, three-way crossover design across 2 sites. Single doses of 4 mg reboxetine, placebo, or 4 mg reboxetine + 5 mg oxybutynin were administered before sleep (order randomized).

RESULTS

Reboxetine reduced the apnea-hypopnea index (primary outcome) by 5.4 (95% confidence interval -10.4 to -0.3) events/h, P = .03 (-24 ± 27% in men; -0.7 ± 32% in women). Oxybutynin did not cause additional reductions in apnea-hypopnea index. Reboxetine alone reduced the 4% oxygen desaturation index by (mean ± standard deviation) 5.2 ± 7.2 events/h and reboxetine+oxybutynin by 5.1 ± 10.6 events/h vs placebo, P = .02. Nadir oxygen saturation also increased by 7 ± 11% with reboxetine and 5 ± 9% with reboxetine+oxybutynin vs placebo, P = .01. Mechanistically, reboxetine and reboxetine+oxybutynin improved pharyngeal collapsibility and respiratory control (loop gain). Larger reductions in apnea-hypopnea index with reboxetine in men were associated with higher baseline loop gain.

CONCLUSIONS

These findings show the first evidence that reboxetine alone reduces OSA severity. The data provide novel insight into the role of norepinephrine reuptake inhibitors on upper airway stability during sleep and are important to inform future pharmacotherapy development for OSA.

CLINICAL TRIAL REGISTRATION

Registry: Australian New Zealand Clinical Trials Registry; Name: Reboxetine and Combination Therapy with AD128 in Sleep Apnoea Trial: A Double-Blind, 3-Way Cross-Over Study; URL: https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=374614&isReview=true; Identifier: ACTRN12620000662965.

CITATION

Altree TJ, Aishah A, Loffler KA, Grunstein RR, Eckert DJ. The norepinephrine reuptake inhibitor reboxetine alone reduces obstructive sleep apnea severity: a double-blind, placebo-controlled, randomized crossover trial. J Clin Sleep Med. 2023;19(1):85-96.

Atomoxetine and fesoterodine combination improves obstructive sleep apnoea severity in patients with milder upper airway collapsibility

BACKGROUND AND OBJECTIVE

The combination of the noradrenergic atomoxetine plus the anti-muscarinic oxybutynin acutely increased genioglossus activity and reduced obstructive sleep apnoea (OSA) severity. However, oxybutynin has shorter half-life than atomoxetine and side effects that might discourage long-term usage. Accordingly, we aimed to test the combination of atomoxetine and fesoterodine (Ato-Feso), a newer anti-muscarinic with extended release formulation, on OSA severity and endotypes.

METHODS

Twelve subjects with OSA underwent a randomized, double-blind, crossover trial comparing one night of atomoxetine plus fesoterodine (80-4 mg) to placebo. Parameters of OSA severity (e.g., apnoea-hypopnoea index [AHI], nadir oxygen desaturation and hypoxic burden) were calculated from two clinical, in-lab polysomnographic studies. OSA endotypes (including collapsibility per VMIN and arousal threshold) were derived from validated algorithms.

RESULTS

Compared to placebo, Ato-Feso did not reduce the AHI (34.2 ± 19.1 vs. 30.1 ± 28.2 events/h, p = 0.493), but reduced the apnoea index (12.9 [28.8] vs. 1.8 [9.1] events/h, median [interquartile range], p = 0.027) and increased nadir desaturation (76.8 [8.0] vs. 82.2 [8.8] %, p = 0.003); a non-significant trend for improved hypoxic burden was observed (52.4 [50.5] vs. 29.7 [78.9] %min/h, p = 0.093). Ato-Feso lowered collapsibility (raised VMIN ; 43.7 [29.8-55.7] vs. 56.8 [43.8-69.8] %VEUPNOEA , mean [CI], p = 0.002), but reduced the arousal threshold (129.3 [120.1-138.6] vs. 116.7 [107.5-126] %VEUPNOEA , p = 0.038). In post hoc analysis, 6/6 patients with milder collapsibility (VMIN  > 43%) exhibited OSA resolution (drop in AHI > 50% and residual AHI < 10 events/h) and improved hypoxaemia.

CONCLUSION

While inefficacious in unselected patients, Ato-Feso administered for one night suppressed OSA in patients with milder collapsibility. Ato-Feso may hold some promise as an alternative OSA treatment in certain subgroups of individuals.

A single dose of noradrenergic/serotonergic reuptake inhibitors combined with an antimuscarinic does not improve obstructive sleep apnoea severity

Previous trials have demonstrated that the combination of noradrenergic reuptake inhibitors with an antimuscarinic can substantially reduce the apnoea-hypopnoea index (AHI) and improve airway collapsibility in patients with obstructive sleep apnoea (OSA). However, some studies have shown that when administered individually, neither noradrenergic or serotonergic agents have been effective at alleviating OSA. This raises the possibility that serotonergic agents (like noradrenergic agents) may also need to be delivered in combination to be efficacious. Therefore, we investigated the effect of an antimuscarinic (oxybutynin) on OSA severity when administered with either duloxetine or milnacipran, two dual noradrenergic/serotonergic reuptake inhibiters. A randomized, double-blind, 4 way cross-over, placebo-controlled trial in ten OSA patients was performed. Patients received each drug condition separately across four overnight in-lab polysomnography (PSG) studies ~1-week apart. The primary outcome measure was the AHI. In addition, the four key OSA endotypes (collapsibility, muscle compensation, arousal threshold, loop gain) were measured non-invasively from the PSGs using validated techniques. There was no significant effect of either drug combinations on reducing the total AHI or improving any of the key OSA endotypes. However, duloxetine+oxybutynin did significantly increase the fraction of hypopnoeas to apnoeas (F_Hypopnoea ) compared to placebo (p = 0.02; d = 0.54). In addition, duloxetine+oxybutynin reduced time in REM sleep (p = 0.009; d = 1.03) which was positively associated with a reduction in the total AHI (R²  = 0.62; p = 0.02). Neither drug combination significantly improved OSA severity or modified the key OSA endotypes when administered as a single dose to unselected OSA patients.

Within-night Repeatability and Long-term Consistency of Sleep Apnea Endotypes: The Multi-Ethnic Study of Atherosclerosis and Osteoporotic Fractures in Men Study

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is characterized by multiple "endotypic traits", including pharyngeal collapsibility, muscle compensation, loop gain, and arousal threshold. Here we examined 1) within-night repeatability, 2) long-term consistency, and 3) influences of body position and sleep state, of endotypic traits estimated from in-home polysomnography in mild-to-severe OSA (apnea-hypopnea index, AHI>5 events/hr).

METHODS

Within-night repeatability was assessed using Multi-Ethnic Study of Atherosclerosis (MESA): Traits derived separately from "odd" and "even" 30-min periods were correlated and regression (error vs. N windows available) provided a recommended amount of data for acceptable repeatability (R-threshold=0.7). Long-term consistency was assessed using the Osteoporotic Fractures in Men Study (MrOS) at two time points 6.5±0.7 years apart, before and after accounting for across-year body position and sleep state differences. Within-night dependence of traits on position and state (MESA plus MrOS data) were estimated using bootstrapping.

RESULTS

Within-night repeatability for traits ranged from R=0.62-0.79 and improved to R=0.69-0.83 when recommended amounts of data were available (20-35 seven-min windows, available in 94-98% of participants); repeatability was similar for collapsibility, loop gain, and arousal threshold (R=0.79-0.83), but lower for compensation (R=0.69). Long-term consistency was modest (R=0.30-0.61) and improved (R=0.36-0.63) after accounting for position and state differences. Position/state analysis revealed reduced loop gain in REM and reduced collapsbility in N3.

CONCLUSIONS

Endotypic traits can be obtained with acceptable repeatability. Long-term consistency was modest but improved after accounting for position and state changes. These data support the use of endotypic assessments in large-scale epidemiological studies.

Efficacy of atomoxetine plus oxybutynin in the treatment of obstructive sleep apnea with moderate pharyngeal collapsibility

Purpose

Preliminary studies have shown a significant decrease in severity of obstructive sleep apnea (OSA) with the use of a combination of atomoxetine and oxybutynin, with patients having moderate pharyngeal collapsibility during sleep more likely to respond. This study evaluated the efficacy and safety of AD036 (atomoxetine 80 mg and oxybutynin 5 mg) in the treatment of OSA.

Methods

This trial was a phase 2, randomized, placebo-controlled crossover study comparing AD036, atomoxetine 80 mg alone, and placebo during three home sleep studies, each separated by about 1 week. The trial included patients with OSA and moderate pharyngeal collapsibility as defined by a higher proportion of hypopneas to apneas and mild oxygen desaturation.

Results

Of 62 patients who were randomized, 60 were included in efficacy analyses. The apnea–hypopnea index (AHI) from a median (interquartile range) of 14.2 (5.4 to 22.3) events/h on placebo to 6.2 (2.8 to 13.6) with AD036 and 4.8 (1.4 to 11.6) with atomoxetine alone (p < .0001). Both drugs also decreased the oxygen desaturation index (ODI) and the hypoxic burden (p < .0001). AD036, but not atomoxetine alone, reduced the respiratory arousal index and improved ventilation at the respiratory arousal threshold (greater V_active). There was a trend for total sleep time to be decreased more with atomoxetine alone than with AD036. The most common adverse event was insomnia (12% with AD036, 18% with atomoxetine).

Conclusion

AD036 significantly improved OSA severity in patients with moderate pharyngeal collapsibility. Atomoxetine may account for the majority of improvement in OSA severity, while the addition of oxybutynin may mitigate the disruptive effect of atomoxetine on sleep and further improve ventilation.

Trial registration

Clinical trial registered with www.clinicaltrials.gov (NCT04445688).