An Official American Thoracic Society Research Statement: Impact of Mild Obstructive Sleep Apnea in Adults

Patients' perceptions of the importance of improvements and side effects from mandibular advancement device therapy for obstructive sleep apnea and snoring

OBJECTIVE

To assess which improvements and side effects are considered most important by patients with OSA treated with a MAD.

METHODS

A specific questionnaire consisting of 20 questions, including 10 questions on improvements and 10 on side effects, was developed and mailed to all subjects (54).

RESULTS

42 patients, participated in the survey by answering the questionnaire. The results showed that patients placed greater importance on the positive outcomes of treatment, with the most significant being the reduction in snoring and improvement in sleep quality. On the other hand, the side effects of difficulty speaking with the device, tooth mobility, and foreign body sensation were considered important.

CONCLUSIONS

The advantages perceived by the patients appear to outweigh the disadvantages, especially the reduction of snoring, increased productivity, and improved social and intellectual life. Most significant side effects are reversible and short-term, while occlusal changes, is not considered important by patients.

Prevalence and Course of Idiopathic Hypersomnia in the Wisconsin Sleep Cohort Study

BACKGROUND AND OBJECTIVES

Idiopathic hypersomnia (IH) is a CNS disorder of hypersomnolence of unknown etiology. Due to the requirement for objective sleep testing to diagnose the disorder, there are currently no population-based estimates of the prevalence of IH nor data regarding the longitudinal course of IH in naturalistic settings.

METHODS

Subjective and objective data from the Wisconsin Sleep Cohort study were used to identify cases with probable IH from participants with polysomnography and multiple sleep latency test data. Demographic, polysomnographic, and symptom-level data were compared between those with and without IH. Longitudinal trajectories of daytime sleepiness among those with IH were assessed to evaluate symptom persistence or remission over time.

RESULTS

From 792 cohort study participants with available polysomnography and multiple sleep latency test data, 12 cases with probable IH were identified resulting in an estimated prevalence of IH of 1.5% (95% CI 0.7-2.5, p < 0.0001). Consistent with inclusion/exclusion criteria, cases with IH had more severe sleepiness and sleep propensity, despite similar or longer sleep times. Longitudinal data (spanning 12.1 ± 4.3 years) demonstrated a chronic course of sleepiness for most of the cases with IH, though pathologic somnolence remitted in roughly 40% of cases.

DISCUSSION

These results demonstrate IH is more common in the working population than generally assumed with a prevalence on par with other common neurologic and psychiatric conditions. Further efforts to identify and diagnose those impaired by unexplained daytime somnolence may help clarify the causes of IH and the mechanisms underlying symptomatic remission.

Incident Coronary Calcium Score in Patients With OSA With and Without Excessive Sleepiness: Brazilian Longitudinal Study of Adult Health

BACKGROUND

Uncertainty exists about the impact of OSA and its phenotypes on cardiovascular disease.

RESEARCH QUESTION

Are OSA and clinical features such as daytime sleepiness associated with incident subclinical coronary atherosclerosis?

STUDY DESIGN AND METHODS

In this prospective community-based cohort study, we administered a sleepiness questionnaire, actigraphy, and home sleep studies at baseline. Coronary artery calcium (CAC; 64-slice multidetector CT scan imaging) was measured at two different time points throughout the study (baseline, between 2010 and 2014, and follow-up, between 2016 and 2018). Incidence of subclinical atherosclerosis was defined as baseline CAC of 0 followed by CAC of > 0 at a 5-year follow-up visit. The association of incident CAC outcome was assessed using logistic regression. Stratified analyses based on excessive daytime sleepiness (EDS) were performed.

RESULTS

We analyzed 1,956 participants with available CAC scores at baseline (mean age, 49 ± 8 years; 57.9% female; 32.4% with OSA). In covariate-adjusted analyses (n = 1,247; mean follow-up, 5.1 ± 0.9 years), we found a significant association between OSA and incidence of subclinical atherosclerosis (OR, 1.26; 95% CI, 1.06-1.48), with stronger effects among those reporting EDS (OR, 1.66; 95% CI, 1.30-2.12; P = .028 for interaction). Interestingly, EDS per se was not associated with any CAC outcome. An exploratory analysis of the square root of CAC progression (baseline CAC > 0 followed by a numerical increase in scores at follow-up; n = 319) showed a positive association for both OSA (β = 1.084; 95% CI, 0.032-2.136; P = .043) and OSA with EDS (β = 1.651; 95% CI, 0.208-3.094; P = .025).

INTERPRETATION

OSA, particularly with EDS, predicts the incidence and progression of CAC. These results support biological plausibility for the increased cardiovascular risk observed among patients with OSA with excessive sleepiness.

The predictive values of BOAH and No-apnea score for screening obstructive sleep apnea in rotating shift worker drivers

Objective

To evaluate the BOAH (Body mass index, Observed apnea, Age, and Hypertension) and No-apnea score's diagnostic values for detecting obstructive sleep apnea (OSA) risk in shift workers.

Methods

Cross-sectional study with male rotating shift workers and drivers of heavy off-road machinery. The BOAH score is based on body mass index, witnessed apneas during sleep, age, and hypertension. The No-apnea score is based on neck circumference and age. Based on the apnea-hypopnea index (AHI), the severity of OSA was categorized as least mild OSA (AHI ≥5/h), moderate to severe OSA (AHI ≥15/h), and severe OSA (AHI ≥30/h). Sensitivity, specificity, positive predictive value, negative predictive value, and areas under the curve (AUC) were calculated.

Results

Among 119 workers evaluated, 84.0% had AHI ≥5, 46.2% had AHI ≥15, and 14.3% had AHI ≥30. BOAH score with 2 points for AHI ≥5, the AUC was 0.679, and sensitivity and specificity were 41.0% and 94.7%, respectively. No-apnea score with 3 points AHI ≥5, the AUC was 0.692, and sensitivity and specificity were 70.0% and 68.4%, respectively. Furthermore, using at least one of the positive scores, the AUC was higher when compared to the single tests for AHI ≥5 (AUC = 0.727). And when both scores were positive, the AUC was higher for AHI ≥30 (AUC = 0.706).

Conclusion

In rotating shift workers and drivers of heavy off-road machinery, BOAH, and No-apnea scores can be helpful tools in identifying individuals at risk for sleep apnea. In addition, matching the scores may increase the prediction of OSA.

Comorbid association of obstructive sleep apnea (OSA) and thrombotic primary antiphospholipid syndrome (tPAPS): A more severe phenotype?

OBJECTIVE

We aimed to evaluate the frequency of obstructive sleep apnea (OSA) in patients with thrombotic primary antiphospholipid syndrome (tPAPS), to investigate the performance of screening tools for OSA in this scenario and to compare clinical/laboratorial differences in tPAPS patients with and without OSA.

METHODS

We consecutively enrolled patients with tPAPS to undergo sleep studies using a portable monitor. OSA was defined as apnea-hypopnea index ≥15 events/h. Frequency of OSA in tPAPS was evaluated and compared with age-, gender-, and BMI-matched controls (1:3 ratio) from the Estudo Longitudinal de Saúde do Adulto (ELSA-Brasil). Next, we tested the performance of three different screening tools for assessing OSA in patients with tPAPS. Finally, patients with tPAPS were stratified according to OSA status comparing their clinical and laboratory characteristics (including damage burden measured by Damage Index for Antiphospholipid Syndrome [DIAPS] and biomarkers associated with thrombosis) using standard statistical procedures.

RESULTS

Fifty-two patients were included for analysis (females: 82.7%; mean age: 48 ± 14 years; body-mass index: 31.1 ± 6.5 Kg/m2; 25% with moderate-severe OSA). When compared to matched controls from ELSA-Brasil (n = 115), there was no significant differences in the frequencies of OSA (tPAPS: 12/42 [28.6%] vs. controls: 35/115 [30.4%], p = 0.821). Among screening tools, NoSAS had the highest area under ROC curve (AUC 0.806, CI 95% 0.672-0.939, p = 0.001), followed by STOP-Bang (AUC 0.772, CI 95% 0.607-0.938, p = 0.004). Patients with comorbid tPAPS and OSA presented higher levels of von Willebrand factor (vWF) (median 38.9 vs. 32.6, p = 0.038) and DIAPS (median 5 vs. 2, p = 0.020), when compared to those without OSA. OSA remained statistically associated with higher DIAPS, even after controlling for age, disease duration and BMI.

CONCLUSION

OSA is common in patients with tPAPS, with rates comparable to a non-referred population. Both NoSAS and STOP-Bang scores seems to be useful for screening OSA in these patients. Patients with tPAPS+OSA had higher damage burden and higher levels of vWF, which might suggest a more severe phenotype of tPAPS in this scenario.

Obstructive sleep apnea and hypertension-mediated organ damage in nonresistant and resistant hypertension

The potential role of obstructive sleep apnea (OSA) in hypertension-mediated organ damage (HMOD) may be influenced by the presence of resistant hypertension (RH). Herein, we enrolled patients with hypertension from a tertiary center for clinical evaluation and performed a sleep study to identify OSA (apnea-hypopnea index ≥15 events/h) and a blinded analysis of four standard HMOD parameters (left ventricular hypertrophy [LVH], increased arterial stiffness [≥10 m/s], presence of retinopathy, and nephropathy). RH was diagnosed based on uncontrolled blood pressure (BP) (≥140/90 mmHg) despite concurrent use of at least three antihypertensive drug classes or controlled BP with concurrent use of ≥4 antihypertensive drug classes at optimal doses. To avoid the white-coat effect, ambulatory BP monitoring was performed to confirm RH diagnosis. One-hundred patients were included in the analysis (mean age: 54 ± 8 years, 65% females, body mass index: 30.4 ± 4.5 kg/m²). OSA was detected in 52% of patients. Among patients with non-RH (n = 53), the presence of OSA (52.8%) was not associated with an increased frequency of HMOD. Conversely, among patients with RH, OSA (51.1%) was associated with a higher incidence of LVH (RH-OSA,61%; RH + OSA,87%; p = 0.049). Logistic regression analysis using the total sample revealed that RH (OR:7.89; 95% CI:2.18-28.52; p = 0.002), systolic BP (OR:1.04; 95% CI:1.00-1.07; p = 0.042) and OSA (OR:4.31; 95% CI:1.14-16.34; p = 0.032) were independently associated with LVH. No significant association was observed between OSA and arterial stiffness, retinopathy, or nephropathy. In conclusion, OSA is independently associated with LVH in RH, suggesting a potential role of OSA in RH prognosis.

Peripheral arterial tonometry versus polysomnography in suspected obstructive sleep apnoea

BACKGROUND

Polysomnography (PSG) is the gold standard for the diagnosis of obstructive sleep apnoea (OSA). Home sleep apnoea testing with peripheral arterial tonometry (PAT) is a recommended diagnostic alternative for patients with an increased risk for OSA. In a large clinical cohort, we investigated concordance and predictors for discordance in diagnosing OSA using PAT and PSG, and three-year cardiovascular risk in patients with discordant OSA diagnosis.

METHODS

Retrospective monocentric cohort study. Patients with a PAT AHI ≥ 5/h followed by an in-hospital PSG within three months were included. All patients with a PAT AHI ≥ 5/h but a PSG AHI < 5/h were classified as discordant. Patients with PAT and PSG AHI ≥ 5/h were classified as concordant. To ascertain cardiovascular risk, major adverse cardiovascular events (MACE) were analyzed in discordant patients and sex, age, body mass index (BMI) and cardiovascular disease-matched concordant patients over a follow-up time of 3.1 ± 0.06 years.

RESULTS

A total of 940 patients, 66% male with an average age of 55 ± 0.4 years and BMI of 31 ± 0.2 kg/m² were included. Agreement in OSA diagnosis was observed in 80% of patients (55% in mild and 86% in moderate and severe OSA). Factors significantly associated with a discordant diagnosis were female sex, younger age and lower BMI, but not comorbidities. There was no significant difference in MACE (p = 0.920) between discordant patients (n = 155) and matched concordant patients (n = 274) with or without therapy.

CONCLUSIONS

Concordance between PAT and PSG diagnosis of sleep apnoea is good, particularly in moderate and severe OSA. Predictors for discordant results between PAT and PSG were age, sex and BMI. MACE risk is similar in those with OSA diagnosed by PAT or PSG.

Overnight declarative memory consolidation and non-rapid eye movement sleep electroencephalographic oscillations in older adults with obstructive sleep apnea

STUDY OBJECTIVES

To compare overnight declarative memory consolidation and non-rapid eye movement (NREM) sleep electroencephalogram (EEG) oscillations in older adults with obstructive sleep apnea (OSA) to a control group and assess slow-wave activity (SWA) and sleep spindles as correlates of memory consolidation.

METHODS

Forty-six older adults (24 without OSA and 22 with OSA) completed a word-pair associate's declarative memory task before and after polysomnography. Recall and recognition were expressed as a percentage of the morning relative to evening scores. Power spectral analysis was performed on EEG recorded at frontal (F3-M2, F4-M1) and central (C3-M2, C4-M1) sites. We calculated NREM absolute slow oscillation (0.25-1 Hz) and delta (0.5-4.5 Hz) EEG power, and slow (11-13 Hz) spindle density (number of events per minute of N2 sleep) and fast (13-16 Hz) spindle density.

RESULTS

There were no significant differences in overnight recall and recognition between OSA (mean age 58.7 ± 7.1 years, apnea-hypopnea index (AHI) 41.9 ± 29.7 events/hour) and non-OSA (age 61.1 ± 10.3 years, AHI 6.6 ± 4.2 events/hour) groups. The OSA group had lower fast spindle density in the frontal region (p = 0.007). No between-group differences in SWA were observed. In the Control group, overnight recognition positively correlated with slow spindle density in frontal (rho = 0.555, p = 0.020) and central regions (rho = 0.490, p = 0.046). Overnight recall was not related to SWA or spindle measures in either group.

CONCLUSIONS

Older adults with OSA had deficits in fast sleep spindles but showed preserved overnight declarative memory consolidation. It is possible that compensatory mechanisms are being recruited by OSA patients to preserve declarative memory consolidation despite the presence of sleep spindle deficits.

Cost-effectiveness of neuromuscular electrical stimulation for the treatment of mild obstructive sleep apnea: an exploratory analysis

OBJECTIVES

To assess the potential cost-effectiveness of neuromuscular electrical stimulation (NMES) for treatment of mild obstructive sleep apnea (OSA).

METHODS

A decision-analytic Markov model was developed to estimate health state progression, incremental cost, and quality-adjusted life year (QALY) gain of NMES compared to no treatment, continuous airway pressure (CPAP), or oral appliance (OA) treatment. The base case assumed no cardiovascular (CV) benefit for any of the interventions, while potential CV benefit was considered in scenario analyses. Therapy effectiveness was based on a recent multi-center trial for NMES, and on the TOMADO and MERGE studies for OA and CPAP. Costs, considered from a United States payer perspective, were projected over lifetime for a 48-year-old cohort, 68% of whom were male. An incremental cost-effectiveness ratio (ICER) threshold of USD150,000 per QALY gained was applied.

RESULTS

From a baseline AHI of 10.2 events/hour, NMES, OA and CPAP reduced the AHI to 6.9, 7.0 and 1.4 events/hour respectively. Long-term therapy adherence was estimated at 65-75% for NMES and 55% for both OA and CPAP. Compared to no treatment, NMES added between 0.268 and 0.536 QALYs and between USD7,481 and USD17,445 in cost, resulting in ICERs between USD15,436 and USD57,844 per QALY gained. Depending on long-term adherence assumptions, either NMES or CPAP were found to be the preferred treatment option, with NMES becoming more attractive with younger age and assuming CPAP was not used for the full night in all patients.

CONCLUSIONS

NMES might be a cost-effective treatment option for patients with mild OSA.

Association between objective sleep measures and cognitive performance: a cross-sectional analysis in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) study

Sleep disturbances often co-exist, which challenges our understanding of their potential impact on cognition. We explored the cross-sectional associations of insomnia and objective measures of sleep with cognitive performance in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) study stratified by middle-aged and older adults. Participants aged ≥55 years underwent cognitive evaluations, polygraphy for 1 night, and actigraphy for 7 days. Insomnia was evaluated using the Clinical Interview Scheduled Revised. Obstructive sleep apnea (OSA) and short sleep duration (SSD) were defined by an apnea-hypopnea index (AHI) of ≥15 events/h and <6 h/ night, respectively. In 703 participants (mean [SD] age 62 [6] years, 44% men), cognition was evaluated using a 10-word list, verbal fluency, and trail-making tests. The frequencies of insomnia, SSD, and OSA were 11%, 24%, and 33%, respectively. In all, 4% had comorbid OSA and insomnia, and 11% had both OSA and SSD. Higher wake after sleep onset (β = -0.004, 95% confidence interval [CI] -0.008, -0.001) and the number of awakenings (β = -0.006, 95% CI -0.012, -0.001) were associated with worse verbal fluency performance. Compared to those without insomnia, older participants with insomnia had worse global performance (β = -0.354, 95% CI -0.671, -0.038). Insomnia was an effect modifier in the associations between AHI and executive function performance (p for the interaction between insomnia and AHI = 0.004) and between oxygen saturation <90% and memory performance (p for the interaction between insomnia and oxygen saturation = 0.02). Although some associations between sleep measures and cognition were significant, they should be considered with caution due to the large sample size and multiple testing performed in this study.

Sleep irregularity and the association with hypertension and blood pressure levels: the ELSA-Brasil study

OBJECTIVE

To evaluate the associations of sleep irregularity with hypertension (HTN) and blood pressure (BP) levels.

METHODS

Adult participants from the ELSA-Brasil performed a clinical evaluation including objective sleep duration (actigraphy), insomnia, and a sleep study for defining obstructive sleep apnoea (OSA). To quantify sleep irregularity, we used two parameters obtained through actigraphy: 7-day standard deviation (SD) of sleep duration and 7-day SD of sleep-onset timing. A multivariate analysis was used to determine the independent associations of sleep irregularity with HTN and SBP/DBP values.

RESULTS

We studied 1720 participants (age 49 ± 8 years; 43.4% men) and 27% fulfilled the HTN diagnosis. After adjustments for age, gender, race, BMI, excessive alcohol consumption, physical activity intensity, urinary sodium excretion, insomnia, objective sleep duration and OSA (apnoea-hypopnoea index ≥15 events/h), we found that the continuous analysis of 7-day SD of sleep duration was modestly associated with prevalent HTN. However, 7-day SD of sleep duration more than 90 min was independently associated with SBP [ β : 1.55; 95% confidence interval (CI) 0.23-2.88] and DBP ( β : 1.07; 95% CI 0.12-2.01). Stratification analysis excluding participants with OSA revealed that a 7-day SD of sleep duration greater than 90 min was associated with a 48% higher chance of having HTN (OR: 1.48; 95% CI: 1.05-2.07). No significant associations were observed for the SD of sleep-onset timing.

CONCLUSION

Objective measurement of sleep irregularity, evaluated by SD of sleep duration for 1 week, was associated with HTN and higher BP levels, especially in participants without OSA.

Excessive daytime sleepiness, but not sleep apnea, sleep duration or insomnia, was associated with poor adherence to anti-hypertensive treatment: The ELSA-Brasil study

Hypertension is the leading risk factor for cardiovascular mortality. Poor adherence may partially explain this scenario. Beyond traditional factors, it is conceivable that sleep conditions such as Obstructive Sleep Apnea (OSA), Sleep Duration (SDUR), sleepiness and insomnia may contribute to impair adherence but the evidence is scanty. Consecutive participants with hypertension from the ELSA-Brasil study performed a home sleep monitoring and 7-days actigraphy to determine OSA (apnea-hypopnea index ≥15 events/hour) and SDUR, respectively. Excessive daytime sleepiness (EDS) and insomnia were evaluated by Epworth Sleepiness Scale (ESS) and Clinical Interview Scheduled Revised (CIS-R), respectively. The 4-itens Morisky questionnaire was used to evaluate adherence to anti-hypertensive therapy. A total of 411 patients were including in the analysis (mean age: 54 ± 8 years, 47% men). Medium/low adherence to anti-hypertensive therapy was observed in 62%. Compared to the high adherence group, the participants with medium/low adherence had lower frequencies of Whites (64.1 vs. 47.8%), high-degree education (50.6 vs. 40%), and monthly per-capita income ($1021.90 vs. $805.20). In contrast, we observed higher frequency of EDS (35.9 vs. 46.1%). No differences were observed for OSA, short SDUR (<6 h) and insomnia. Logistic regression analysis showed that race other than White (OR: 1.80; 95% IC:1.15-2.82), lower monthly income (OR: 1.74; 95% IC:1.01-3.0) and EDS (OR: 1.63; 95% IC:1.05-2.53) were independently associated with medium/low adherence to the anti-hypertensive treatment. Interestingly, EDS mediated the abdominal obesity-adherence outcome. In conclusion, among sleep-related parameters, EDS, but not OSA, short SDUR or insomnia, were associated to impaired adherence to anti-hypertensive therapy.

Functional Outcomes of Swallowing Following Surgery for Obstructive Sleep Apnea

OBJECTIVE

Identification and evaluation of swallowing dysfunction in patients undergoing upper airway surgery for obstructive sleep apnea (OSA) is limited. This study evaluated subjective swallowing function pre and postoperatively in patients undergoing multi-level reconstructive pharyngeal sleep surgery.

METHODS

A retrospective analysis of prospectively-administered Eating Assessment Tool (EAT-10) scores was conducted among adult patients undergoing surgery for OSA at a tertiary sleep surgery center. Preoperative and 1, 3, and 6-month postoperative time points were assessed. Patients were subdivided into two groups based on the degree of upper airway reconstruction performed. All patients underwent uvulopalatopharyngoplasty +/-tonsillectomy and tongue-base reduction. Patients undergoing Phase 1 reconstructive surgery additionally underwent tongue-base advancement procedures.

RESULTS

A total 100 patients underwent airway reconstructive surgery. Forty-one patients underwent Phase 1 surgery; 59 patients underwent Mini-Phase 1 surgery. Neither group demonstrated preoperative dysphagia. Both groups experienced significant subjective dysphagia at 1-month postoperatively, which was greater among Phase 1 patients (mean EAT-10 14.8; SD 10.4) versus Mini-Phase 1 patients (mean EAT-10 6.7; SD 7.5) (p < 0.001). Swallowing function among both groups normalized by 3 and 6 months postoperatively. Phase 1 patients with pre-operative dysphagia (mean EAT-10 9.6; SD 5) demonstrated initial worsening of their swallowing postoperatively; however, reported improved swallowing versus pre-operative levels by 6 months postoperatively (mean EAT-10 3.6; SD 4.3) (p = 0.03).

CONCLUSION

Pharyngeal surgery resulted in no significant, persistent adverse change in swallowing function. Among both groups, significant subjective dysphagia was reported at 1 month postoperatively, yet returned to preoperative levels by 6 months postoperatively. OSA patients with pre-existing dysphagia undergoing Phase 1 surgery trended towards improved swallowing function postoperatively.

LEVEL OF EVIDENCE

2 Laryngoscope, 133:199-204, 2023.

Effects of CPAP on Metabolic Syndrome in Patients With OSA: A Randomized Trial

BACKGROUND

OSA is associated with metabolic syndrome (MS), but it is unclear whether OSA treatment with CPAP can revert MS.

RESEARCH QUESTION

Does OSA treatment with CPAP per se have effects on the MS reversibility and the associated metabolic, adiposity and vascular parameters?

STUDY DESIGN AND METHODS

The TREATOSA-MS trial is a randomized placebo-controlled trial that enrolled adult patients with a recent diagnosis of MS and moderate or severe OSA (apnea-hypopnea index [AHI], ≥ 15 events/h) to undergo therapeutic CPAP or nasal dilator strips (placebo group) for 6 months. Before and after each intervention, we measured anthropometric variables, BP, glucose, and lipid profile. To control potential-related mechanisms and consequences, we also measured adiposity biomarkers (leptin and adiponectin), body composition, food intake, physical activity, subcutaneous and abdominal fat (visceral and hepatic fat), and endothelial function.

RESULTS

One hundred patients (79% men; mean age, 48 ± 9 years; BMI, 33 ± 4 kg/m²; AHI, 58 ± 29 events/h) completed the study (n = 50 per group). The mean CPAP adherence was 5.5 ± 1.5 h/night. After 6 months, most patients with OSA randomized to CPAP retained the MS diagnosis, but the rate of MS reversibility was higher than observed in the placebo group (18% vs 4%; OR, 5.27; 95% CI, 1.27-35.86; P = .04). In the secondary analysis, CPAP did not promote significant reductions in the individual components of MS, weight, hepatic steatosis, lipid profile, adiponectin, and leptin, but did promote a very modest reduction in visceral fat and improved endothelial function (all analyses were adjusted for baseline values).

INTERPRETATION

Despite the higher rate of MS reversibility after CPAP therapy as compared with placebo, most patients retained this diagnosis. The lack of significant or relevant effects on adiposity biomarkers and depots supports the modest role of OSA in modulating MS.

TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT02295202; URL: www.

CLINICALTRIALS

gov.

Scoring heart rate increases as a surrogate arousal marker on portable monitor studies for obstructive sleep apnea: Impact on diagnostic accuracy and clinical decision-making

Cortical arousal-related hypopneas are not scored on type 3 home devices, which therefore limits their diagnostic accuracy for obstructive sleep apnea. The objective of this study was to evaluate whether scoring heart rate accelerations as surrogate markers of arousal improves type 3 portable monitor diagnostic agreement compared with polysomnography and improves therapeutic decision-making. We prospectively recruited patients evaluated for obstructive sleep apnea to undergo in-laboratory simultaneous full polysomnography + type 3 portable monitoring. Hypopnea events were scored on portable monitor studies with and without autonomic scoring, which was defined as an associated increase in pulse oximetry-derived heart rate ≥6 beats per min (autonomic hypopnea). Portable monitor diagnostic agreement compared with polysomnography with and without autonomic hypopnea scoring was assessed. We also evaluated whether reporting autonomic hypopnea scoring improves portable monitor clinical treatment decision agreement after four physicians reviewed clinical data and sleep study results (polysomnography, portable monitor with autonomic hypopnea, portable monitor without autonomic hypopnea). Eighty-two participants completed simultaneous polysomnography and in-laboratory portable monitor studies. Scoring autonomic hypopnea resulted in a decreased mean difference between in-laboratory portable monitor respiratory event index and polysomnography apnea-hypopnea index in Bland-Altman analysis (mean difference 14.6 per hr without versus 6.1 per hr with autonomic hypopnea scoring [p ˂ 0.01]), and increased intraclass correlation from 0.769 to 0.844. Inclusion of autonomic hypopnea scoring resulted in better accuracy between portable monitor and polysomnography expert's treatment decisions, and ultimately resulted in 24% fewer additional polysomnographies requested. The addition of pulse oximetry heart rate increases for autonomic hypopnea scoring during portable monitor resulted in better diagnostic agreement, improved clinical decision-making and reduced additional polysomnography testing.

A transition to the AASM recommended hypopnea definition in adults: initiatives of the Hypopnea Scoring Rule Task Force

The American Academy of Sleep Medicine (AASM) recommends that hypopneas be identified using a definition that is based on a ≥30% decrease in airflow associated with a ≥3% reduction in the oxygen saturation or an arousal (H3A) for diagnosis of obstructive sleep apnea (OSA) in adults. This conflicts with the Centers for Medicare and Medicaid Services (CMS) definition, which requires a ≥4% decrease in the oxygen saturation to identify a hypopnea (H4) and does not acknowledge arousals. In 2018, the AASM board of directors constituted a Hypopnea Scoring Rule Task Force (HSRTF) with a mandate to "create a strategy for adoption and implementation of the AASM recommended adult hypopnea scoring criteria among members, payers and device manufacturers." The task force initiated several activities including a survey of AASM accredited laboratories and discussions with polysomnography software vendors. Survey results indicated that most laboratories scored polysomnograms using only the CMS definition. Vendors indicated that they could easily support dual scoring. Informal testing among task force members' laboratories confirmed there would be little additional work if dual scoring was performed. The task force convened several meetings of a working group of OSA content experts and interested parties, with the purpose of creating research recommendations to study the impact on relevant clinical outcomes using the different definitions of hypopnea. Several possible prospective and retrospective approaches were discussed with emphasis on the group of patients diagnosed with OSA based on an apnea-hypopnea index (AHI) using H3A but NOT H4. Based on the deliberations of the working group, the HSRTF submitted recommendations to the AASM Foundation concerning research project strategies for potential grant funding. Further discussions within the HSRTF focused on developing advocacy initiatives among patient stakeholder groups to change payer policy.

Cardiovascular and metabolic effects of a mandibular advancement device and continuous positive airway pressure in moderate obstructive sleep apnea: a randomized controlled trial

STUDY OBJECTIVES

It has been suggested that treatment for obstructive sleep apnea (OSA) reduces cardiovascular risk. So far, knowledge is limited about the difference in the reduction of this risk between mandibular advancement device (MAD) and continuous positive airway pressure (CPAP) therapy. The aim of this study was to compare the cardiovascular effects of MAD versus CPAP therapy in patients with moderate OSA.

METHODS

Patients with an apnea-hypopnea index (AHI) of 15-30 events/h were randomized to either MAD or CPAP therapy. At baseline and after 12-months follow-up, 24-hour ambulant blood pressure measurements (ABPM) and laboratory measurements were performed. ABPM consisted of 24-hour, daytime and night-time systolic (SBP) and diastolic blood pressure (DBP), and heart rate (HR) measurements. Laboratory measurements consisted of serum lipid values, creatinine, high-sensitivity c-reactive protein, plasma glucose, hemoglobin A1c (HbA1c), proinflammatory cytokines, soluble receptor for advanced glycation end products (sRAGE), chemokines and adhesion molecules.

RESULTS

Of the 85 randomized patients with moderate OSA, data were available for 54 patients (n=24 MAD, n=30 CPAP) at 12-month follow-up and showed that AHI significantly decreased with either therapy. In the MAD group, sRAGE and HbA1c were significantly higher after 12 months follow-up compared to baseline. No significant changes were found between MAD and CPAP treatment for all outcomes.

CONCLUSIONS

Treatment of patients with moderate OSA with either MAD or CPAP therapy had no profound effects on major cardiovascular risk factors after 12-months.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Title: MRA Therapy Versus CPAP Therapy in Moderate OSAS; Identifier: NCT01588275; URL: https://clinicaltrials.gov/ct2/show/NCT01588275.

Self-reported versus actigraphy-assessed sleep duration in the ELSA-Brasil study: analysis of the short/long sleep duration reclassification

PURPOSE

This study was aimed to determine the magnitude and predictors of self-reported short/long sleep duration (SDUR) reclassifications using objective measurements.

METHODS

Adult participants from the ELSA-Brasil study performed self-reported SDUR, 7-day wrist actigraphy, and a portable sleep study. We explored two strategies of defining self-reported SDUR reclassification: (1) short and long SDUR defined by <6 and ≥8h, respectively; (2) reclassification using a large spectrum of SDUR categories (<5, 5-6, 7-8, 8-9, and >9 h).

RESULTS

Data from 2036 participants were used in the final analysis (43% males; age: 49±8 years). Self-reported SDUR were poorly correlated (r=0.263) and presented a low agreement with actigraphy-based total sleep time. 58% of participants who self-reported short SDUR were reclassified into the reference (6-7.99 h) or long SDUR groups using actigraphy data. 88% of participants that self-reported long SDUR were reclassified into the reference and short SDUR. The variables independently associated with higher likelihood of self-reported short SDUR reclassification included insomnia (3.5-fold), female (2.5-fold), higher sleep efficiency (1.35-fold), lowest O₂ saturation (1.07-fold), higher wake after sleep onset (1.08-fold), and the higher number of awakening (1.05-fold). The presence of hypertension was associated with a 3.4-fold higher chance of self-reported long SDUR reclassification. Analysis of five self-reported SDUR categories revealed that the more extreme is the SDUR, the greater the self-reported SDUR reclassification.

CONCLUSION

In adults, we observed a significant rate of short/long SDUR reclassifications when comparing self-reported with objective data. These results underscore the need to reappraise subjective data use for future investigations addressing SDUR.

OSA patients not treated with PAP - Evolution over 5 years according to the Baveno classification and cardiovascular outcomes

INTRODUCTION

The evolution of patients with obstructive sleep apnea (OSA) non-eligible for PAP-therapy at diagnosis is unknown. Currently, the severity of OSA is based on the apnea-hypopnea index (AHI), but its prognostic relevance has raised concerns. The Baveno classification may allow a better stratification of severity and therapeutic guidance in OSA.

METHODS

Patients with AHI≥5/h in 2015, classified into Baveno groups A and B and non-eligible for PAP therapy at diagnosis and over 5 years, were analyzed. Patients were reclassified into Baveno groups (A-D) and changes in groups over 5 years were explored. Patients in Baveno groups C and D, who developed major cardiovascular comorbidities (CVC) or end-organ damage (EOD group), were compared with patients in Baveno groups A and B (non-EOD group). To identify predictors of the development of major CVC or EOD, a logistic regression analysis was performed.

RESULTS

There were 76 patients, 58% male, mean age 51.9 ± 10.1 years, mean body mass index (BMI) of 30.3 ± 5.0 kg/m2 and median AHI of 8.9 (5.9-12.0) events/h. At diagnosis, 46% and 54% of patients were classified into Baveno group A and group B, respectively. In total, 21% of patients developed major CVC or EOD (Baveno group C or D); higher age (p = 0.011) and BMI (p = 0.004) and a higher percentage of central apneas (p = 0.012) at diagnosis significantly predicted it, while sex, sleepiness, insomnia, AHI, ODI and T90 were not.

CONCLUSIONS

A significant percentage of patients non-eligible for PAP-therapy at diagnosis of OSA developed CVC or EOD; higher age and BMI and a higher percentage of central apneas were significant predictors.

Mortality prediction in chronic obstructive pulmonary disease and obstructive sleep apnea

BACKGROUND

We aimed to assess mortality in chronic obstructive pulmonary disease (COPD), obstructive sleep apnea (OSA), and overlap syndrome, and evaluate which polysomnographic indices-apnea-hypopnea index (AHI) or hypoxemic load measurements-better predict mortality within 10 years.

METHODS

Adults with symptoms suggestive of sleep apnea and airway disease who underwent both polysomnography and spirometry plus bronchodilator response tests between 2000 and 2018 were included and divided into four groups according to presence of COPD and moderate-to-severe OSA (AHI ≥15/h). We estimated mortality using a Cox model adjusted for demographic/anthropometric covariates and comorbidities; this was called clinical model. To evaluate prognostic performance, we compared the concordance index (C-index) between clinical model and extended models, which incorporated one of polysomnographic indices-AHI, sleep time spent with SpO₂ < 90% (TS90), and mean and lowest SpO₂.

RESULTS

Among 355 participants, patients with COPD alone (57/355, 16.1%) and COPD-OSA overlap syndrome (37/355, 10.4%) had increased all-cause mortality than those who had neither disease (152/355, 42.8%) (adjusted HR, 2.98 and 3.19, respectively). The C-indices of extended models with TS90 (%) and mean SpO₂ were significantly higher than that of clinical model (0.765 vs. 0.737 and 0.756 vs. 0.737, respectively; all P < 0.05); however, the C-index of extended model with AHI was not (0.739 vs. 0.737; P = 0.15).

CONCLUSIONS

In this cohort with symptoms of sleep apnea and airway disease, patients with overlap syndrome had increased mortality, but not higher than in those with COPD alone. The measurement of hypoxemic load, not AHI, better predicted mortality.

Obstructive Sleep Apnea in Patients with Chronic Obstructive Pulmonary Disease: Facts and Perspectives

The co-occurrence of obstructive sleep apnea (OSA) and chronic obstructive pulmonary disease (COPD) in the same patient, named the overlap syndrome (OS), was first described in 1985. Although the American Thoracic Society underlined the limited knowledge of OS, stated research priorities for this condition, and recommended a "screening" strategy to identify OSA in COPD patients with chronic stable hypercapnia, research studies on OS remain scarce. This review aims to summarize the current knowledge and perspectives related to OSA in COPD patients. OS prevalence is 1.0-3.6% in the general population, 3-66% in COPD patients, and 7-55% in OSA patients. OS patients may have worse sleep quality than those with OSA or COPD alone. Scoring hypopneas may be difficult in COPD patients; desaturation episodes may have origins in these patients, namely upper airway obstruction, hypoventilation during paradoxical sleep, ventilation/perfusion mismatches, and obesity. The apnea-hypopnea index is similar in OSA and OS patients. Desaturations may be greater and more prolonged in OS patients than in patients with COPD or OSA alone. Low body mass index, hyperinflation, and less collapsible airways reduce the risk of OSA in COPD patients. OSA is a risk factor for pulmonary hypertension in COPD patients. Whether OS increases mortality and morbidity risks compared to COPD or OSA alone remains to be confirmed. No guidelines currently recommend specific approaches to the treatment of OSA in patients with COPD.

Prevalence of objective excessive daytime sleepiness in a cohort of patients with mild obstructive sleep apnea

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is common, yet the relationship between mild OSA and excessive daytime sleepiness (EDS) is unclear. Our objective was to determine the prevalence of objective EDS in a population with mild OSA using the mean sleep latency (MSL) from the multiple sleep latency test (MSLT).

METHODS

We retrospectively analyzed 1205 consecutive patients who underwent a polysomnography and a following day MSLT at a single sleep center. Adult patients who met criteria for mild OSA with an apnea-hypopnea index of 5 to <15 events/h were identified, and the percentage of patients with a MSL ≤ 8 min was determined. Sleep study and demographic variables were examined to evaluate predictors of objective EDS.

RESULTS

Of 155 patients with mild OSA, objective EDS was found in 36% (56/155) with an average MSL of 5.6 ± 2.1 min in the objectively sleepy patients. Objectively sleepy patients with mild OSA had greater total sleep time (411.6 ± 48.9 vs. 384.5 ± 61.7 min, p = 0.004), increased sleep efficiency (84.9 ± 9.7 vs. 79.7 ± 12.7%, p = 0.01), and decreased wake after sleep onset time (53.0 ± 36.9 vs. 67.4 ± 46.1 min, p = 0.04) compared to patients with mild OSA but without objective EDS, with total sleep time being an independent predictor of MSL (p = 0.006). The Epworth Sleepiness Scale (ESS) weakly correlated with objective EDS (ρ =  - 0.169, p = 0.03).

CONCLUSIONS

There is a large subgroup of patients with mild OSA patients who have objective sleepiness. This may represent an ideal subgroup to target for future studies examining the effect of treatment in mild OSA. Additionally, the ESS was a poor predictor of this subgroup with mild OSA and objective EDS.

Association of Sodium with Obstructive Sleep Apnea. The ELSA-Brasil Study

Rationale: Excessive sodium may have a role in the pathogenesis of obstructive sleep apnea (OSA) for patients with hypervolemic conditions, but it is unclear whether this is valid for all patients with OSA, including those with no significant comorbidities.Objectives: To test the association of urinary sodium and OSA in a large sample of participants from the ELSA-Brasil (Estudo Longitudinal de Saúde do Adulto-Brasil) Study. In addition, we stratified the analysis participants according to the presence of hypertension.Methods: In this cross-sectional study, OSA was defined by an apnea-hypopnea index ≥15 events/h. A validated 12-hour urine collection as representative of the 24-hour period was obtained from all participants to measure sodium excretion. We performed a logistic regression analysis to test the association of urinary sodium excretion with OSA (dependent variable) adjusting for age, sex, race and income, glomerular filtration rate, diabetes, physical activity, and antihypertensive classes related to sodium excretion. To address potential residual factors that may influence sodium excretion, we performed additional analysis replacing sodium excretion for salt intake (food frequency questionnaire) using the same models.Results: We studied 1,946 participants (age 49 ± 8 yr; 43.4% men). A third of them had OSA. Compared with those with no OSA, participants with OSA presented with higher sodium excretion (1.66 [1.19-2.29] vs. 1.99 [1.44-2.69] g/12 h; P < 0.001). After adjustments for confounding factors, we found no overall significant associations of sodium excretion with OSA (odds ratio [OR], 1.09; 95% confidence interval [CI], 0.97-1.23; P = 0.150). Regardless of the OSA status, the sodium excretion was higher in hypertensive than in normotensive participants (1.93 [1.35-2.64] vs. 1.71 [1.22-2.37] g/12 h). An independent association of sodium excretion with OSA was observed in patients with hypertension only (OR, 1.326; 95% CI, 1.067-1.648; P = 0.011), but the interaction of urinary sodium with hypertension was not significant (P = 0.37). The analysis of salt intake revealed consistent findings.Conclusions: The potential role of sodium in the pathogenesis of OSA seems to be modest and limited for those with higher salt intake and, consequently, higher fluid retention such as observed in patients with hypertension.

Development and validation of a model for diagnosis of obstructive sleep apnoea in primary care

BACKGROUND AND OBJECTIVE

Use of in-laboratory polysomnography (PSG) to diagnose obstructive sleep apnoea (OSA) is cost and resource intensive. Questionnaires, physical measurements and home monitors have been studied as potential simpler alternatives. This study aimed to develop a diagnostic model for OSA for use in primary care.

METHODS

Primary care practitioners were trained to recognize symptoms of sleep apnoea and recruited patients based on the clinical need to investigate OSA. Assessment was by symptom questionnaires, anthropomorphic measurements, digital facial photography, and a single-channel nasal flow monitor (Flow Wizard©, DiagnoseIT, Sydney, Australia) worn at home for 3 nights. The in-laboratory PSG was the reference test, with OSA defined as apnoea-hypopnoea index (AHI) ≥10 events/h.

RESULTS

In the model development phase, 25 primary care practitioners studied 315 patients in whom they suspected OSA, of which 57% had AHI≥10 and 22% had AHI≥30. Published OSA questionnaires provided low to moderate prediction of OSA (area under the curve [AUC] 0.53-0.73). The nasal flow monitor alone yielded high accuracy for predicting OSA with AUC of 0.87. Sensitivity was 0.87 and specificity 0.77 at a threshold respiratory event index (REI) of 18 events/h. A model adding age, gender, symptoms and BMI to the nasal flow monitor REI only modestly improved OSA prediction (AUC 0.89), with similar AUC (0.88) confirmed in the validation population of 114 patients.

CONCLUSION

Sleep apnoea can be diagnosed in the primary care setting with a combination of clinical judgement and portable monitor test outcomes.

Depression and obesity, but not mild obstructive sleep apnea, are associated factors for female sexual dysfunction

PURPOSE

Mild obstructive sleep apnea (OSA) is more prevalent than moderate and severe OSA and is more frequent in men than women. The association between OSA and female sexual dysfunction (FSD) is still poorly explored in published studies. Our aim was to investigate the prevalence of FSD in women with mild OSA and assess the impact of OSA on FSD, as well as to determine the predictors for FSD risk.

METHODS

The sample comprised 70 women aged 26-65 years: a control group (N = 28) with no sleep complaints, and a group with mild OSA (an apnea-hypopnea index of  5 or more and less than 15 events/hour, N = 42), who had been diagnosed using polysomnography performed in the sleep laboratory of a sleep research institute. All participants volunteered to take part in the study and completed the female sexual function index (FSFI), the Beck depression index (BDI), the Kupperman menopausal index (KMI), and the Epworth sleepiness scale (ESS). Their socioeconomic group was assessed using the Brazilian Economic Classification Criterion. Polysomnography and serum levels of free testosterone and total testosterone were analyzed.

RESULTS

We found low FSFI scores (< 26.55) in the mild OSA (18.1) and control (21.7) groups (p = 0.97). There was no statistically significant difference between the mild OSA group and the control group. However, a higher BMI (p = 0.04), a higher BDI (p = 0.02), and being sexuality inactive (p = 0.001) were risk factors for FSD.

CONCLUSION

There was a high prevalence of FSD in the entire sample. The presence of mild OSA did not affect sexual function in this sample. Depressive symptoms and a high BMI were associated risk factors for FSD. Being sexually active may protect female sexual function.

Frequency of flow limitation using airflow shape

STUDY OBJECTIVES

The presence of flow limitation during sleep is associated with adverse health consequences independent of obstructive sleep apnea (OSA) severity (apnea-hypopnea index, AHI), but remains extremely challenging to quantify. Here we present a unique library and an accompanying automated method that we apply to investigate flow limitation during sleep.

METHODS

A library of 117,871 breaths (N=40 participants) were visually classified (certain flow limitation, possible flow limitation, normal) using airflow shape and physiological signals (ventilatory drive per intra-esophageal diaphragm EMG). An ordinal regression model was developed to quantify flow limitation certainty using flow-shape features (e.g. flattening, scooping); breath-by-breath agreement (Cohen's ƙ) and overnight flow limitation frequency (R 2, %breaths in certain or possible categories during sleep) were compared against visual scoring. Subsequent application examined flow limitation frequency during arousals and stable breathing, and associations with ventilatory drive.

RESULTS

The model (23 features) assessed flow limitation with good agreement (breath-by-breath ƙ=0.572, p<0.001) and minimal error (overnight flow limitation frequency R 2=0.86, error=7.2%). Flow limitation frequency was largely independent of AHI (R 2=0.16) and varied widely within individuals with OSA (74[32-95]%breaths, mean[range], AHI>15/hr, N=22). Flow limitation was unexpectedly frequent but variable during arousals (40[5-85]%breaths) and stable breathing (58[12-91]%breaths), and was associated with elevated ventilatory drive (R 2=0.26-0.29; R 2<0.01 AHI v. drive).

CONCLUSIONS

Our method enables quantification of flow limitation frequency, a key aspect of obstructive sleep-disordered breathing that is independent of the AHI and often unavailable. Flow limitation frequency varies widely between individuals, is prevalent during arousals and stable breathing, and reveals elevated ventilatory drive.

The treatment of mild OSA with CPAP or mandibular advancement device and the effect on blood pressure and endothelial function after one year of treatment

STUDY OBJECTIVES

To evaluate and compare the effects of continuous positive airway pressure (CPAP), use of a mandibular advancement device (MAD), and no treatment on 24-hour ambulatory blood pressure monitoring and peripheral arterial tonometry at 6 and 12 months follow-up in individuals with mild obstructive sleep apnea (OSA), and in a subgroup who had an apnea-hypopnea index of < 5 events/h and adherence of ≥ 4 hours per night (effective-treatment subgroups).

METHODS

The inclusion criteria were individuals with mild obstructive sleep apnea, any sex, age between 18 and 65 years, and a body mass index of ≤ 35 kg/m². Patients were randomized into CPAP, MAD, and no-treatment groups. The evaluations included physical examination, full polysomnography, 24-hour ambulatory blood pressure monitoring, and peripheral arterial tonometry at baseline and after 6 and 12 months. A generalized linear mixed model was used for comparisons.

RESULTS

The CPAP and MAD groups had lower apnea-hypopnea indexes than the control group at 6 and 12 months, and the CPAP group had higher blood oxygen levels (SpO₂) than the MAD group. The MAD group had more hours of treatment per night and better adaptation to treatment than the CPAP group (MAD: 5.7 ± 2.7 h/night; CPAP: 3.8 ± 3.4 h/night; MAD: 16% did not adapt; CPAP: 42% did not adapt). No differences were found in the total sample and effective treatment in relation to peripheral arterial tonometry or 24-hour ambulatory blood pressure monitoring outcomes.

CONCLUSIONS

Treatment of mild obstructive sleep apnea with CPAP or MAD did not improve blood pressure or endothelial function after 1 year, even in patients with effective treatment.

CLINICAL TRIAL REGISTRATION

Registry: ClinicalTrials.gov; Name: Continuous Positive Airway Pressure and Oral Appliances Treatments in Mild Obstructive Sleep Apnea; URL: https://clinicaltrials.gov/ct2/show/NCT01461486; Identifier: NCT01461486.

Mild obstructive sleep apnea increases hypertension risk, challenging traditional severity classification

STUDY OBJECTIVES

The association of mild obstructive sleep apnea (OSA) with important clinical outcomes remains unclear. We aimed to investigate the association between mild OSA and systemic arterial hypertension (SAH) in the European Sleep Apnea Database cohort.

METHODS

In a multicenter sample of 4,732 participants, we analyzed the risk of mild OSA (subclassified into 2 groups: mild_{AHI 5-<11/h} (apnea-hypopnea index [AHI], 5 to <11 events/h) and mild_{AHI 11-<15/h} (AHI, ≥11 to <15 events/h) compared with nonapneic snorers for prevalent SAH after adjustment for relevant confounding factors including sex, age, smoking, obesity, daytime sleepiness, dyslipidemia, chronic obstructive pulmonary disease, type 2 diabetes, and sleep test methodology (polygraphy or polysomnography).

RESULTS

SAH prevalence was higher in the mild_{AHI 11-<15/h} OSA group compared with the mild_{AHI 5-<11/h} group and nonapneic snorers (52% vs 45% vs 30%; P < .001). Corresponding adjusted odds ratios for SAH were 1.789 (mild_{AHI 11-<15/h}; 95% confidence interval [CI], 1.49-2.15) and 1.558 (mild_{AHI 5-<11/h}; 95%, CI, 1.34-1.82), respectively (P < .001). In sensitivity analysis, mild_{AHI 11-<15/h} OSA remained a significant predictor for SAH both in the polygraphy (odds ratio, 1.779; 95% CI, 1.403-2.256; P < .001) and polysomnography groups (odds ratio, 1.424; 95% CI, 1.047-1.939; P = .025).

CONCLUSIONS

Our data suggest a dose-response relationship between mild OSA and SAH risk, starting from 5 events/h in polygraphy recordings and continuing with a further risk increase in the 11- to <150-events/h range. These findings potentially introduce a challenge to traditional thresholds of OSA severity and may help to stratify participants with OSA according to cardiovascular risk.

Cardiovascular and somatic comorbidities and sleep measures using three hypopnea criteria in mild obstructive sleep-disordered breathing: sex, age, and body mass index differences in a retrospective sleep clinic cohort

STUDY OBJECTIVES

To describe sex, age, and body mass index (BMI) differences in comorbidities and polysomnography measures, categorized using 3 different apnea-hypopnea index (AHI) criteria in sleep clinic patients with mild obstructive sleep-disordered breathing.

METHODS

A retrospective cohort of 305 (64% female) adult sleep clinic patients who underwent full-night in-laboratory polysomnography having been diagnosed with mild sleep-disordered breathing and prescribed positive airway pressure. Effects of sex, age, and BMI on comorbidities and polysomnography measures, including rates of AHI defined by ≥ 3% desaturations (AHI_3%), with arousals (AHI_3%A), by ≥ 4% desaturations (AHI_4%), and by respiratory disturbance index, were evaluated.

RESULTS

Sixty-nine (23%), 116 (38%), 258 (85%), and 267 (88%) patients had AHI_4%, AHI_3%, AHI_3%A, and respiratory disturbance index ≥ 5 events/h, respectively. Ninety-day positive airway pressure adherence rates were 45.9% overall and higher in women > 50-years-old (51.2%, P = 0.013) and men (54.5%, P = 0.024) with no difference whether AHI_4% or AHI_3%A was < 5 or ≥ 5 events/h. Men and women had similar rates of daytime sleepiness (43.3%), anxiety (44.9%), and hypertension (44.9%). Women were more likely to have obesity, anemia, asthma, depression, diabetes, fibromyalgia, hypothyroidism, migraine, and lower rates of coronary artery disease. More patients with AHI_4% < 5 events/h had depression, migraines, and anemia, and more patients with AHI_4% ≥ 5 events/h had congestive heart failure. Women were more likely to have higher sleep maintenance and efficiency, shorter average obstructive apnea and hypopnea durations, and less supine-dominant pattern. Average obstructive apnea and hypopnea duration decreased with increasing BMI, and average hypopnea duration increased with age. Obstructive apnea duration and obstructive hypopnea with arousal duration decreased with increasing BMI. More women had AHI_4% < 5 (81.5% vs 69.1%), AHI_3% < 5 (68.7% vs 49.1%), and AHI_3%A < 5 events/h (18.5% vs 10.0%). Greater age and higher BMI were associated with higher AHI.

CONCLUSIONS

Current AHI criteria do not predict comorbidities or adherence in mild sleep-disordered breathing patients. In this hypothesis-generating descriptive analysis, sex, BMI, and age may all be factors that should be accounted for in future research of mild sleep-disordered breathing patients. Different sleep study measures may weigh differently in calculations of risk for cardiovascular versus somatic comorbidities.

The differential impact of respiratory event scoring criteria on CPAP eligibility in women and men

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is more prevalent and severe in men than women. The American Academy of Sleep Medicine (AASM) offers 2 definitions for scoring hypopneas: "acceptable" = associated with a >4% oxygen desaturation, adopted by Center for Medicare and Medicaid Services (CMS), and "recommended" = associated with a >3% oxygen desaturation and / or an arousal. We hypothesized that CMS versus AASM scoring criteria would differentially impact continuous positive airway pressure (CPAP) eligibility in women and men.

METHODS

We conducted a retrospective review of adult diagnostic in-lab polysomnography (PSG) at an urban academic institution. All PSGs were scored by both CMS and AASM scoring criteria, and an analysis by sex was performed that took into account demographics and other PSG variables.

RESULTS

Of 969 PSGs reviewed, 674 (69.6%) were in women. Women were younger (51.5 vs. 53.3 y/o) and had a higher body mass index (BMI 38.6 kg/m² vs. 33.8 kg/m²) but had similar Epworth Sleepiness Scale scores when compared to men. The odds of an AASM AHI > 5 being missed by CMS scoring in women was 1.89 (95% CI: 1.40-2.53; p<0.001) compared to men and increased to 6.87 among women 40-60 years of age with a BMI≥40 kg/m². After controlling for age, BMI, % REM sleep and mean oxygen saturation, the sex effect remained significant (OR 1.87; 95% CI: 1.36-2.58; p<0.001).

CONCLUSIONS

CMS scoring criteria imparts a sex bias towards women potentially resulting in denial of therapy to symptomatic women with OSA. Larger, prospective cohort studies are needed to confirm these findings.

Titration studies overestimate continuous positive airway pressure requirements in uncomplicated obstructive sleep apnea

STUDY OBJECTIVES

Attended manual CPAP titration is the standard practice for determining optimal positive airway pressures for OSA treatment. However, an unattended single night auto-titrating positive airway pressure (APAP) titration is an alternative. The goal of this study was to determine whether therapeutic CPAP pressures determined during manual titrations are higher than APAP generated surrogate pressures.

METHODS

We conducted a retrospective review of 165 adults with uncomplicated OSA who had full/split-night manual CPAP titrations prior to commencing treatment with APAP. Demographic and clinical data including 30-day APAP compliance data were obtained. We compared the recommended CPAP pressure from manual titrations with the 90th/95th percentile pressure generated from APAP usage over 30 days.

RESULTS

The recommended CPAP pressures during the manual titrations were higher than the 90th/95th percentile pressures generated from APAP. (11.4 ± 3.4 vs. 10.3 ± 2.4, p=0.000). Almost half the group (41.9%) had their manually derived titration pressure at least 1.5 cm above the 90th/95th percentile pressure. In multivariate analyses, BMI was the only variable that predicted higher manual titration pressures. Notably, the average residual AHI on 30-day APAP data was less than the average residual AHI observed at the recommended pressure during the manual titration (5.0 ± 4.3 vs. 7.2 ± 8.5, p= 0.006).

CONCLUSIONS

Manual CPAP titrations may overestimate pressure requirements particularly in patients with higher BMI and may not be necessary in managing patients with uncomplicated OSA. APAP appears to be at least as effective as single pressure CPAP, while delivering lower positive airway pressure.

Sex differences in the association between arterial hypertension, blood pressure, and sleep apnea in the general population

STUDY OBJECTIVES

To assess sex-related differences in the relationship between hypertension (HT), blood pressure (BP), and sleep apnea in the general population.

METHODS

We performed home polygraphy in a cohort of 1809 men and women in the general population. Office BP was measured. Presence of HT (drug-treated, physician-diagnosed, or high BP during study visit) was also recorded. HT rate and BP were assessed over a range of 7 sleep apnea severity categories based on the respiratory event index (REI).

RESULTS

The age-adjusted HT prevalence rate increased with higher REI in both sexes. After additional adjustment for obesity the association remained significant in women but not in men. In participants not treated with antihypertensive medications, age-adjusted BP increased with REI. Remarkably, the association was already significant within the normal range (REI < 5 events/h). The REI threshold for higher BP was situated at a distinctly lower cutoff point in women compared to men. After additional adjustment for obesity, the associations remained significant for diastolic but not systolic BP.

CONCLUSIONS

Significant increases in the age-adjusted BP and HT rate in the general population were present at lower REI cutoffs in women compared to men. Even a very low number of respiratory events was associated with higher BP and HT prevalence. Adjustment for obesity attenuated these associations, especially in men. Sex differences in BP susceptibility across the sleep apnea spectrum may be present.

Daytime Neuromuscular Electrical Therapy of Tongue Muscles in Improving Snoring in Individuals with Primary Snoring and Mild Obstructive Sleep Apnea

Study Objectives: Evaluating daytime neuromuscular electrical training (NMES) of tongue muscles in individuals with Primary Snoring and Mild Obstructive Sleep Apnea (OSA). Methods: A multicenter prospective study was undertaken in patients with primary snoring and mild sleep apnea where daytime NMES (eXciteOSA^® Signifier Medical Technologies Ltd., London W6 0LG, UK) was used for 20 min once daily for 6 weeks. Change in percentage time spent snoring was analyzed using a two-night sleep study before and after therapy. Participants and their bed partners completed sleep quality questionnaires: Epworth Sleepiness Scale (ESS) and Pittsburgh Sleep Quality Index (PSQI), and the bed partners reported on the nighttime snoring using a Visual Analogue Scale (VAS). Results: Of 125 patients recruited, 115 patients completed the trial. Ninety percent of the study population had some reduction in objective snoring with the mean reduction in the study population of 41% (p < 0.001). Bed partner-reported snoring reduced significantly by 39% (p < 0.001). ESS and total PSQI scores reduced significantly (p < 0.001) as well as bed partner PSQI (p = 0.017). No serious adverse events were reported. Conclusions: Daytime NMES (eXciteOSA^®) is demonstrated to be effective at reducing objective and subjective snoring. It is associated with effective improvement in patient and bed partner sleep quality and patient daytime somnolence. Both objective and subjective measures demonstrated a consistent improvement. Daytime NMES was well tolerated and had minimal transient side effects.

The Association of Sleep Apnea and Cardiorespiratory Fitness With Long-Term Major Cardiovascular Events

OBJECTIVE

To determine the risk of long-term major adverse cardiovascular events (MACE) when sleep-disordered breathing (SDB) and decreased cardiorespiratory fitness (CRF) co-occur.

METHODS

We included consecutive patients who underwent symptom-limited cardiopulmonary exercise tests between January 1, 2005, and January 1, 2010, followed by first-time diagnostic polysomnography within 6 months. Patients were stratified based on the presence of moderate-to-severe SDB (apnea/hypopnea index ≥15 per hour) and decreased CRF defined as <70% predicted peak oxygen consumption (VO₂). Long-term MACE was a composite outcome of myocardial infarction (MI), coronary artery bypass graft (CABG), percutaneous coronary intervention (PCI), stroke or transient ischemic attack (TIA), and death, assessed until May 21, 2018. Cox-proportional hazard models were adjusted for factors known to influence CRF and MACE.

RESULTS

Of 498 included patients (60±13 years, 28.1% female), 175 (35%) had MACE (MI=17, PCI=14, CABG=13, stroke=20, TIA=12, deaths=99) at a median follow-up of 8.7 years (interquartile range=6.5 to 10.3 years). After adjusting for age, sex, beta blockers, systemic hypertension, diabetes mellitus, coronary artery disease, cardiac arrhythmia, chronic obstructive pulmonary disease, smoking, and use of positive airway pressure (PAP), decreased CRF alone (hazard ratio [HR]=1.91, 95% confidence interval [CI], 1.15 to 3.18; P=.01), but not SDB alone (HR=1.26, 95% CI, 0.75 to 2.13, P=.39) was associated with increased risk of MACE. Those with SDB and decreased CRF had greater risk of MACE compared with patients with decreased CRF alone (HR=1.85; 95% CI, 1.21 to 2.84; P<.005) after accounting for these confounders. The risk of MACE was attenuated in those with reduced CRF alone after additionally adjusting for adequate adherence to PAP (HR=1.59; 95% CI, 0.77 to 3.31; P=.21).

CONCLUSION

The incidence of MACE, especially mortality, was high in this sample. Moderate-to-severe SDB with concurrent decreased CRF was associated with higher risk of MACE than decreased CRF alone. These results highlight the importance of possibly including CRF in the risk assessment of patients with SDB and, conversely, that of screening for SDB in patients with low peak VO₂.

Obstructive sleep apnea is associated with lower adiponectin and higher cholesterol levels independently of traditional factors and other sleep disorders in middle-aged adults: the ELSA-Brasil cohort

PURPOSE

Obstructive sleep apnea (OSA) may contribute to metabolic and inflammatory deregulation but previous studies failed to consider sleep duration, sleep fragmentation, insomnia, and daytime sleepiness as potential confounders.

METHODS

Consecutive non-diabetic middle-aged participants from the ELSA-Brasil cohort were invited to perform a clinical evaluation, home sleep study for 1 night, and wrist actigraphy for 7 days. OSA was defined by an apnea-hypopnea index ≥ 15 events/h. Participants were stratified according to the presence of OSA measuring the following markers: fasting glucose, glucose tolerance test, homeostatic model assessment of insulin resistance (HOMA-IR) index, fasting insulin, insulin after 2 h of glucose load, glycated hemoglobin, total cholesterol and their fractions, triglycerides, C-reactive protein, TNF-alpha, interleukin-6, interleukin-10, leptin, adiponectin, E-selectin, ADMA, MCP-1, TGF, apolipoprotein B, fibrinogen, and lipoprotein(a). Differences between groups were identified by chi-square test and ANOVA.

RESULTS

We studied 708 participants (mean age: 46 ± 5 years, men: 44%, BMI 26.1 ± 4.1 kg/m²). Compared to no OSA, participants with OSA presented higher levels while fasting and after 2 h glucose load of insulin, HOMA-IR, cholesterol, triglycerides, and C-reactive protein (all p < 0.001). After linear regression analysis adjusting for traditional risk factors plus sleep duration, fragmentation, insomnia, and daytime sleepiness, OSA was negatively associated with adiponectin (β = - 0.271 CI 95% - 0.456 - 0.085) and positively associated with cholesterol (β = 9.707 CI 95% 2.737 16.678). Sex-stratification revealed that these associations were significant for men but not women.

CONCLUSIONS

In non-diabetic middle-age adults, men with OSA presented with lower adiponectin and higher cholesterol levels independently of sleep duration, sleep fragmentation, insomnia, and daytime sleepiness.

Obstructive Sleep Apnea, Sleep Duration, and Associated Mediators With Carotid Intima-Media Thickness: The ELSA-Brasil Study

[Figure: see text].

The effects of continuous positive airway pressure and mandibular advancement therapy on metabolic outcomes of patients with mild obstructive sleep apnea: a randomized controlled study

BACKGROUND

Moderate and severe obstructive sleep apnea (OSA) have been independently associated with dyslipidemia. The results of metabolic improvement with continuous positive airway pressure (CPAP) have been controversial. Less evidence exists regarding this issue in mild OSA. A current treatment for mild OSA is mandibular advancement device (MAD) therapy, but its effectiveness on the metabolic profile needs to be compared with CPAP. The purpose of this study was to compare MAD vs CPAP vs no treatment on the metabolic profile during 6 and 12 months of follow-up in patients with mild OSA.

METHODS

The inclusion criteria were patients with mild OSA, both genders, ages 18 to 65 years, and body mass index (BMI) of < 35 Kg/m². Patients were randomized in 3 groups (CPAP, MAD, and control). The evaluations included physical examination, metabolic profile, and full polysomnography at baseline, 6 months, and 12 months of follow-up.

RESULTS

Seventy-nine patients with mild OSA were randomized in three treatment groups, with mean age (± SD) of 47 ± 9 years, 54% men, and AHI 9.5 ± 2.9 events/h. MAD and CPAP reduced AHI at 6 and 12 months compared to the control group. MAD adherence was higher than CPAP at 6 and 12 months. Despite lower adherence compared to MAD, CPAP was more effective in reducing total cholesterol over 12 months (baseline 189.3 ± 60.2 mg/dl to 173.4 ± 74.3 mg/dl) and low-density lipoprotein cholesterol (LDL-c, baseline 112.8 ± 54.9 mg/dl to 94.5 ± 67.4 mg/dl).

CONCLUSIONS

After 1 year of treatment, CPAP was superior to MAD in reducing total cholesterol and LDL-c in patients with mild OSA.

Altered REM sleep architecture in patients with Myotonic dystrophy type 1: is related to sleep apnea?

OBJECTIVE

To determine the sleep architecture and sleep respiratory abnormalities and to correlate with sleep symptoms in patients with Myotonic dystrophy type 1 (DM1).

METHODS

We recruited a cohort of genetically confirmed patients with DM1, who attended the Neuromuscular clinic between July 2016 and December 2019. Clinical, sleep and whole night polysomnography data were collected. The analysis of sleep architecture, sleep respiratory parameters and comparison with healthy controls (HC) was performed in our sleep laboratory.

RESULTS

A total of 59 patients with DM1 underwent sleep evaluation. Hypersomnolence in 42 (77.8%), ESS>10 in 23 (39%), and PSQI>5 in 18 (30.5%) were found in patients with DM1. Thirty-one (68.89%) patients with DM1 and 22 (95.65%) HC had more than 4-h of total sleep time (TST). More than 4 h of TST was taken to compare respiratory and sleep architecture parameters. Patients with DM1 had reduced sleep efficiency, reduced N2 sleep, and increase in N1 sleep, wake index, stage shift index, nocturnal sleep-onset REM periods compared to HC. AHI>15 was found in 16 (51.61%) DM1 and in 3 HC (13.64%). AHI had positive correlation with BMI, but not with age, ESS or disease progression (MIRS). All DM1 with AHI>15; 8(80%) and 1(33.33%) in AHI5to15, and AHI<5 groups, respectively had hypersomnolence.

CONCLUSION

In this first study on Indian cohort, daytime hypersomnolence, poor nocturnal sleep quality, sleep architecture irregularities are identified to be common in patients with DM1. These abnormalities may be explained by sleep-related breathing disorders that are highly prevalent in these patients.

The effect of continuous positive airway pressure on blood pressure in patients with obstructive sleep apnea and uncontrolled hypertension - Study design and challenges during the COVID-19 pandemic

OBJECTIVES

To describe the MORPHEOS (Morbidity in patients with uncontrolled HTN and OSA) trial, and describe the challenges imposed by the COVID-19 pandemic.

METHODS

MORPHEOS is a multicenter (n=6) randomized controlled trial designed to evaluate the blood pressure (BP) lowering effects of treatment with continuous positive airway pressure (CPAP) or placebo (nasal strips) for 6 months in adult patients with uncontrolled hypertension (HTN) and moderate-to-severe obstructive sleep apnea (OSA). Patients using at least one antihypertensive medication were included. Uncontrolled HTN was confirmed by at least one abnormal parameter in the 24-hour ABPM and ≥80% medication adherence evaluated by pill counting after the run-in period. OSA was defined by an apnea-hypopnea index ≥15 events/hours. The co-primary endpoints are brachial BP (office and ambulatory BP monitoring, ABPM) and central BP. Secondary outcomes include hypertension-mediated organ damage (HMOD) to heart, aorta, eye, and kidney. We pre-specified several sub-studies from this investigation. Visits occur once a week in the first month and once a month thereafter. The programmed sample size was 176 patients but the pandemic prevented this final target. A post-hoc power analysis will be calculated from the final sample. ClinicalTrials.gov: NCT02270658.

RESULTS

The first 100 patients are predominantly males (n=69), age: 52±10 years, body mass index: 32.7±3.9 kg/m2 with frequent co-morbidities.

CONCLUSIONS

The MORPHEOS trial has a unique study design including a run-in period; pill counting, and detailed analysis of hypertension-mediated organ damage in patients with uncontrolled HTN that will allow clarification of the impact of OSA treatment with CPAP.

The implementation of a physical activity intervention in adults with Obstructive Sleep Apnoea over the age of 50 years: a feasibility uncontrolled clinical trial

Background

Obstructive Sleep Apnoea (OSA) is a risk factor for cardiovascular disease (CVD) and Type 2 diabetes (T2D). Observational studies suggested that OSA treatment might reduce CVD and T2D but RCTs failed to support these observations in part due to poor adherence to continuous positive airway pressure (CPAP). Physical activity (PA) has been shown to have favourable impact on CVD and the risk of T2D independent of its impact on weight and therefore might provide additional health gains to patients with OSA, whether or not adherent to CPAP.

Methods

The main aim of this study was to explore the feasibility of providing a 12-week PA intervention to adults aged over 50 with OSA. The secondary aim was to assess the impact of the PA intervention on OSA severity. Patients with moderate-severe OSA (apnoea hypopnea index (AHI) ≥ 15 events/hour (based on overnight ApneaLink™) were recruited in response to posters displayed in workplaces. A 12-week daily PA intervention was delivered in participant’s home setting and PA was monitored via text and validated by objective PA measures (GT3X accelerometers).

Results

The intervention was feasible as all 10 patients (8 males, mean (SD) age 57.3 (6.01)) completed the intervention and PA increased across the 12-weeks. The duration of PA increased from baseline (113.1 min (64.69) per week to study-end following the intervention (248.4 min (148.31) (p = 0.02). Perceived Exertion (RPE) (physical effort) increased significantly between baseline (M = 10.7 (1.94)) to end of intervention (M = 13.8, (1.56) (p < 0.001). The intervention had no significant impact on weight or composition. Following the intervention, there was a statistically non-significant a reduction in AHI from baseline to study end (22.3 (7.35) vs. 15.8 (7.48); p = 0.09).

Conclusion

It is feasible to deliver a PA intervention to adults aged over 50 with OSA. The intervention resulted in improved PA and AHI levels somewhat and seemingly independent of weight changes. Future trials need to examine whether PA can reduce the burden of OSA associated comorbidities.

Trial registration

CTN: ISRCTN11016312 Retrospectively Registered 21/07/20.

Use of the WatchPAT to detect occult residual sleep-disordered breathing in patients on CPAP for obstructive sleep apnea

STUDY OBJECTIVES

To determine the accuracy of the apnea-hypopnea index (AHI) as measured by continuous positive airway pressure (CPAP) machines by simultaneously employing a home sleep apnea testing device (WatchPAT 200, Itamar Medical, Israel [WPAT]) in patients suspected of having residual sleep-disordered breathing (SDB).

METHODS

Patients with new, recurrent, or worsening signs, symptoms, or comorbidities associated with obstructive sleep apnea underwent home sleep apnea testing using WPAT while simultaneously using CPAP at their usual prescribed settings. CPAP AHI and WPAT AHI, respiratory disturbance index, and oximetry readings were then compared.

RESULTS

We identified an elevated AHI with WPAT testing in nearly half of patients with clinically suspected residual SDB and a normal CPAP AHI. WPAT detected additional respiratory events as well, including rapid eye movement-related apneas, respiratory effort-related arousals, and hypoxemia.

CONCLUSIONS

WPAT AHI was significantly higher than simultaneous CPAP AHI in nearly half of those patients with clinically suspected residual SDB being treated with CPAP. Additional respiratory disturbances, including rapid eye movement-related respiratory events, respiratory effort-related arousals, and hypoxemia, were elucidated only with the use of the WPAT. Residual SDB may have potential clinical consequences, including reduced CPAP adherence, ongoing hypersomnolence, and other health-related sequelae. Simultaneous WPAT testing of patients with a normal CPAP AHI may represent a valuable tool to detect clinically suspected residual SDB or to ensure adequate treatment in high-risk patients with obstructive sleep apnea in general.

Sleep Duration and Efficiency Associated With Better Functional Exercise Capacity in Black Smokers at Risk for COPD

BACKGROUND

Black smokers have earlier development of lung disease as well as poorer sleep health than whites.

RESEARCH QUESTION

In a sample of black smokers, to what extent does sleep health modify the association between smoking level and functional exercise capacity?

DESIGN AND METHODS

Cross-sectional data from 209 black smokers (≥ 1 cigarette in last month), aged 40 to 65 years with no evidence of sleep-disordered breathing (apnea-hypopnea index < 15) or severe COPD (FEV₁ > 50%), were used for the current study. Self-reported smoking rate, objectively measured sleep efficiency (SE), total sleep time (TST), and the 6-min walk test (6MWT) for functional exercise capacity were the key assessments.

RESULTS

The mean age was 54.8 years (SD, 5.96), and mean cigarettes smoked per day (cpd) was 8.71 (SD, 6.78). Mean SE was 69.9% (SD, 12.3%), and mean TST was 307.99 min (SD 92.2). In adjusted linear regression models of the 6MWT (meters), TST (slope estimate, -0.14; P = .14) and SE (slope estimate, -1.0; P = .19) were negatively associated with 6MWT. The smoking rate × SE interaction was highly significant (slope estimate, 0.18; P = .007) such that in individuals who smoked ≥ 10 cpd, every additional percentage of SE garnered an additional distance of 0.83 to 6.62 m. Similarly, the smoking rate × TST interaction was significant (slope estimate, 0.019; P = .03) such that in smokers who smoked ≥ 10 cpd, every additional minute of TST garnered an additional distance of 0.04 to 0.60 m.

INTERPRETATION

Higher SE and, to a lesser extent, longer TST, in black adults who smoke ≥ 10 cpd is associated with better 6MWT performance.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov; No.: NCT03534076; URL: www.clinicaltrials.gov.