A proposed multi-domain, digital model for capturing functional status and health-related quality of life in oncology

Whereas traditional oncology clinical trial endpoints remain key for assessing novel treatments, capturing patients' functional status is increasingly recognized as an important aspect for supporting clinical decisions and assessing outcomes in clinical trials. Existing functional status assessments suffer from various limitations, some of which may be addressed by adopting digital health technologies (DHTs) as a means of collecting both objective and self-reported outcomes. In this mini-review, we propose a device-agnostic multi-domain model for oncology capturing functional status, which includes physical activity data, vital signs, sleep variables, and measures related to health-related quality of life enabled by connected digital tools. By using DHTs for all aspects of data collection, our proposed model allows for high-resolution measurement of objective data as patients navigate their daily lives outside of the hospital setting. This is complemented by electronic questionnaires administered at intervals appropriate for each instrument. Preliminary testing and practical considerations to address before adoption are also discussed. Finally, we highlight multi-institutional pre-competitive collaborations as a means of successfully transitioning the proposed digitally enabled data collection model from feasibility studies to interventional trials and care management.

Adenotonsillectomy for Snoring and Mild Sleep Apnea in Children: A Randomized Clinical Trial

Importance

The utility of adenotonsillectomy in children who have habitual snoring without frequent obstructive breathing events (mild sleep-disordered breathing [SDB]) is unknown.

Objectives

To evaluate early adenotonsillectomy compared with watchful waiting and supportive care (watchful waiting) on neurodevelopmental, behavioral, health, and polysomnographic outcomes in children with mild SDB.

Design, Setting, and Participants

Randomized clinical trial enrolling 459 children aged 3 to 12.9 years with snoring and an obstructive apnea-hypopnea index (AHI) less than 3 enrolled at 7 US academic sleep centers from June 29, 2016, to February 1, 2021, and followed up for 12 months.

Intervention

Participants were randomized 1:1 to either early adenotonsillectomy (n = 231) or watchful waiting (n = 228).

Main Outcomes and Measures

The 2 primary outcomes were changes from baseline to 12 months for caregiver-reported Behavior Rating Inventory of Executive Function (BRIEF) Global Executive Composite (GEC) T score, a measure of executive function; and a computerized test of attention, the Go/No-go (GNG) test d-prime signal detection score, reflecting the probability of response to target vs nontarget stimuli. Twenty-two secondary outcomes included 12-month changes in neurodevelopmental, behavioral, quality of life, sleep, and health outcomes.

Results

Of the 458 participants in the analyzed sample (231 adenotonsillectomy and 237 watchful waiting; mean age, 6.1 years; 230 female [50%]; 123 Black/African American [26.9%]; 75 Hispanic [16.3%]; median AHI, 0.5 [IQR, 0.2-1.1]), 394 children (86%) completed 12-month follow-up visits. There were no statistically significant differences in change from baseline between the 2 groups in executive function (BRIEF GEC T-scores: -3.1 for adenotonsillectomy vs -1.9 for watchful waiting; difference, -0.96 [95% CI, -2.66 to 0.74]) or attention (GNG d-prime scores: 0.2 for adenotonsillectomy vs 0.1 for watchful waiting; difference, 0.05 [95% CI, -0.18 to 0.27]) at 12 months. Behavioral problems, sleepiness, symptoms, and quality of life each improved more with adenotonsillectomy than with watchful waiting. Adenotonsillectomy was associated with a greater 12-month decline in systolic and diastolic blood pressure percentile levels (difference in changes, -9.02 [97% CI, -15.49 to -2.54] and -6.52 [97% CI, -11.59 to -1.45], respectively) and less progression of the AHI to greater than 3 events/h (1.3% of children in the adenotonsillectomy group compared with 13.2% in the watchful waiting group; difference, -11.2% [97% CI, -17.5% to -4.9%]). Six children (2.7%) experienced a serious adverse event associated with adenotonsillectomy.

Conclusions

In children with mild SDB, adenotonsillectomy, compared with watchful waiting, did not significantly improve executive function or attention at 12 months. However, children with adenotonsillectomy had improved secondary outcomes, including behavior, symptoms, and quality of life and decreased blood pressure, at 12-month follow-up.

Trial Registration

ClinicalTrials.gov Identifier: NCT02562040.

Study protocol: A comparison of mobile and clinic-based spirometry for capturing the treatment effect in moderate asthma

Several inefficiencies in drug development trial implementation may be improved by moving data collection from the clinic to mobile, allowing for more frequent measurements and therefore increased statistical power while aligning to a patient-centric approach to trial design. Sensor-based digital health technologies such as mobile spirometry (mSpirometry) are comparable to clinic spirometry for capturing outcomes, such as forced expiratory volume in 1 s (FEV1); however, the impact of remote spirometry measurements on the detection of treatment effect has not been investigated. A protocol for a multicenter, single-arm, open-label interventional trial of long-acting beta agonist (LABA) therapy among 60 participants with uncontrolled moderate asthma is described. Participants will complete twice-daily mSpirometry at home and clinic spirometry during weekly visits, alongside continuous use of a wrist-worn wearable and regular completion of several diaries capturing asthma symptoms as well as participant- and site-reported satisfaction and ease of use of mSpirometry. The co-primary objectives of this study are (A) to quantify the treatment effect of LABA therapy among participants with moderate asthma, using both clinical spirometry (FEV1c ) and mSpirometry (FEV1m ); and (B) to investigate whether FEV1m is as accurate as FEV1c in detecting the treatment effect using a mixed-effect model for repeated measures. Study results will help inform whether the deployment of mSpirometry and a wrist-worn wearable for remote data collection are feasible in a multicenter setting among participants with moderate asthma, which may then be generalizable to other populations with respiratory disease.

Scoring sleep with artificial intelligence enables quantification of sleep stage ambiguity: hypnodensity based on multiple expert scorers and auto-scoring

STUDY OBJECTIVES

To quantify the amount of sleep stage ambiguity across expert scorers and to validate a new auto-scoring platform against sleep staging performed by multiple scorers.

METHODS

We applied a new auto-scoring system to three datasets containing 95 PSGs scored by 6-12 scorers, to compare sleep stage probabilities (hypnodensity; i.e. the probability of each sleep stage being assigned to a given epoch) as the primary output, as well as a single sleep stage per epoch assigned by hierarchical majority rule.

RESULTS

The percentage of epochs with 100% agreement across scorers was 46 ± 9%, 38 ± 10% and 32 ± 9% for the datasets with 6, 9, and 12 scorers, respectively. The mean intra-class correlation coefficient between sleep stage probabilities from auto- and manual-scoring was 0.91, representing excellent reliability. Within each dataset, agreement between auto-scoring and consensus manual-scoring was significantly higher than agreement between manual-scoring and consensus manual-scoring (0.78 vs. 0.69; 0.74 vs. 0.67; and 0.75 vs. 0.67; all p < 0.01).

CONCLUSIONS

Analysis of scoring performed by multiple scorers reveals that sleep stage ambiguity is the rule rather than the exception. Probabilities of the sleep stages determined by artificial intelligence auto-scoring provide an excellent estimate of this ambiguity. Compared to consensus manual-scoring, sleep staging derived from auto-scoring is for each individual PSG noninferior to manual-scoring meaning that auto-scoring output is ready for interpretation without the need for manual adjustment.

Verification, analytical validation and clinical validation (V3) of wearable dosimeters and light loggers

Background

Light exposure is an important driver and modulator of human physiology, behavior and overall health, including the biological clock, sleep-wake cycles, mood and alertness. Light can also be used as a directed intervention, e.g., in the form of light therapy in seasonal affective disorder (SAD), jetlag prevention and treatment, or to treat circadian disorders. Recently, a system of quantities and units related to the physiological effects of light was standardized by the International Commission on Illumination (CIE S 026/E:2018). At the same time, biometric monitoring technologies (BioMeTs) to capture personalized light exposure were developed. However, because there are currently no standard approaches to evaluate the digital dosimeters, the need to provide a firm framework for the characterization, calibration, and reporting for these digital sensors is urgent.

Objective

This article provides such a framework by applying the principles of verification, analytic validation and clinical validation (V3) as a state-of-the-art approach for tools and standards in digital medicine to light dosimetry.

Results

This article describes opportunities for the use of digital dosimeters for basic research, for monitoring light exposure, and for measuring adherence in both clinical and non-clinical populations to light-based interventions in clinical trials.

Recommendations for Defining and Reporting Adherence Measured by Biometric Monitoring Technologies: Systematic Review

Background

Suboptimal adherence to data collection procedures or a study intervention is often the cause of a failed clinical trial. Data from connected sensors, including wearables, referred to here as biometric monitoring technologies (BioMeTs), are capable of capturing adherence to both digital therapeutics and digital data collection procedures, thereby providing the opportunity to identify the determinants of adherence and thereafter, methods to maximize adherence.

Objective

We aim to describe the methods and definitions by which adherence has been captured and reported using BioMeTs in recent years. Identifying key gaps allowed us to make recommendations regarding minimum reporting requirements and consistency of definitions for BioMeT-based adherence data.

Methods

We conducted a systematic review of studies published between 2014 and 2019, which deployed a BioMeT outside the clinical or laboratory setting for which a quantitative, nonsurrogate, sensor-based measurement of adherence was reported. After systematically screening the manuscripts for eligibility, we extracted details regarding study design, participants, the BioMeT or BioMeTs used, and the definition and units of adherence. The primary definitions of adherence were categorized as a continuous variable based on duration (highest resolution), a continuous variable based on the number of measurements completed, or a categorical variable (lowest resolution).

Results

Our PubMed search terms identified 940 manuscripts; 100 (10.6%) met our eligibility criteria and contained descriptions of 110 BioMeTs. During literature screening, we found that 30% (53/177) of the studies that used a BioMeT outside of the clinical or laboratory setting failed to report a sensor-based, nonsurrogate, quantitative measurement of adherence. We identified 37 unique definitions of adherence reported for the 110 BioMeTs and observed that uniformity of adherence definitions was associated with the resolution of the data reported. When adherence was reported as a continuous time-based variable, the same definition of adherence was adopted for 92% (46/50) of the tools. However, when adherence data were simplified to a categorical variable, we observed 25 unique definitions of adherence reported for 37 tools.

Conclusions

We recommend that quantitative, nonsurrogate, sensor-based adherence data be reported for all BioMeTs when feasible; a clear description of the sensor or sensors used to capture adherence data, the algorithm or algorithms that convert sample-level measurements to a metric of adherence, and the analytic validation data demonstrating that BioMeT-generated adherence is an accurate and reliable measurement of actual use be provided when available; and primary adherence data be reported as a continuous variable followed by categorical definitions if needed, and that the categories adopted are supported by clinical validation data and/or consistent with previous reports.

Neighborhoods with Greater Prevalence of Minority Residents Have Lower Continuous Positive Airway Pressure Adherence

Rationale: Limited data suggest racial disparities in continuous positive airway pressure (CPAP) adherence exist.Objectives: To assess whether CPAP adherence varies by neighborhood racial composition at a national scale.Methods: Telemonitoring data from a CPAP manufacturer database were used to assess adherence in adult patients initiating CPAP therapy between November 2015 and October 2018. Mapping ZIP code to ZIP code tabulation areas, age- and sex-adjusted CPAP adherence data at a neighborhood level was computed as a function of neighborhood racial composition. Secondary analyses adjusted for neighborhood education and poverty.Measurements and Main Results: Among 787,236 patients living in 26,180 ZIP code tabulation areas, the prevalence of CPAP adherence was 1.3% (95% confidence interval [CI], 1.0-1.6%) lower in neighborhoods with high (⩾25%) versus low (<1%) percentages of Black residents and 1.2% (95% CI, 0.9-1.5%) lower in neighborhoods with high versus low percentages of Hispanic residents (P < 0.001 for both), even after adjusting for neighborhood differences in poverty and education. Mean CPAP usage was similar across neighborhoods for the first 2 days, but by 90 days, differences in CPAP usage increased to 22 minutes (95% CI, 18-27 min) between neighborhoods with high versus low percentages of Black residents and 22 minutes (95% CI 17-27 min) between neighborhoods with high versus low percentages of Hispanic residents (P < 0.001 for both).Conclusions: CPAP adherence is lower in neighborhoods with greater proportions of Black and Hispanic residents, independent of education or poverty. These differences lead to a lower likelihood of meeting insurance coverage requirements for CPAP therapy, potentially exacerbating sleep health disparities.

Estimating sleep stages using cardiorespiratory signals: validation of a novel algorithm across a wide range of sleep-disordered breathing severity

STUDY OBJECTIVES

We have developed the CardioRespiratory Sleep Staging (CReSS) algorithm for estimating sleep stages using heart rate variability and respiration, allowing for estimation of sleep staging during home sleep apnea tests. Our objective was to undertake an epoch-by-epoch validation of algorithm performance against the gold standard of manual polysomnography sleep staging.

METHODS

Using 296 polysomnographs, we created a limited montage of airflow and heart rate and deployed CReSS to identify each 30-second epoch as wake, light sleep (N1 + N2), deep sleep (N3), or rapid eye movement (REM) sleep. We calculated Cohen's kappa and the percentage of accurately identified epochs. We repeated our analyses after stratification by sleep-disordered breathing (SDB) severity, and after adding thoracic respiratory effort as a backup signal for periods of invalid airflow.

RESULTS

CReSS discriminated wake/light sleep/deep sleep/REM sleep with 78% accuracy; the kappa value was 0.643 (95% confidence interval, 0.641-0.645). Discrimination of wake/sleep demonstrated a kappa value of 0.711 and accuracy of 89%, non-REM sleep/REM sleep demonstrated a kappa of 0.790 and accuracy of 94%, and light sleep/deep sleep demonstrated a kappa of 0.469 and accuracy of 87%. Kappa values did not vary by more than 0.07 across subgroups of no SDB, mild SDB, moderate SDB, and severe SDB. Accuracy increased to 80%, with a kappa value of 0.680 (95% confidence interval, 0.678-0.682), when CReSS additionally utilized the thoracic respiratory effort signal.

CONCLUSIONS

We observed substantial agreement between CReSS and the gold-standard comparator of manual sleep staging of polysomnographic signals, which was consistent across the full range of SDB severity. Future research should focus on the extent to which CReSS reduces the discrepancy between the apnea-hypopnea index and the respiratory event index, and the ability of CReSS to identify REM sleep-related obstructive sleep apnea.

Prevalence of sleepiness and associations with quality of life in patients with sleep apnea in an online cohort

STUDY OBJECTIVES

Excessive daytime sleepiness (EDS) is a treatment target for many patients with obstructive sleep apnea (OSA). We aimed to understand the prevalence, risk factors and quality of life associated with EDS in a non-clinical, "real world" sample of patients with OSA.

METHODS

Cross-sectional survey of patients with OSA participating in an online peer support community, assessing demographics, comorbidities, treatment, and quality of life. Differences in those with and without EDS (Epworth Sleepiness Scale [ESS] > and ≤ 10) were assessed.

RESULTS

The sample (n=422) was 54.2% male, 65.9% were ≥ 55 years, and 43.3% reported sleeping ≤ 6 hours/night. EDS was identified among 31.0% of respondents and 51.7% reported sleepiness as a precipitating factor for seeking initial OSA treatment. EDS was more prevalent in individuals reporting asthma, insomnia symptoms, positive airway pressures (PAP) use less than 6 hours/night on ≥ 5 nights/week, or sleep duration < 6 hours/night. After adjusting for demographics and comorbidities, patients with EDS reported poorer mental and physical health and well-being, lower disease-specific functional status, more activity and work impairment, and more driving impairment (p values < 0.05). In the sub-sample (n=265) with high PAP adherence, 26.0% reported EDS, and similar associations between EDS and outcomes were observed.

CONCLUSIONS

These "real-world" data suggest that patients seeking online OSA support experience a high prevalence of EDS, which was associated with poorer quality of life and worse functional status. Associations persisted among respondents with high self-reported PAP-adherence, potentially driving these individuals to seek online support for sleepiness-related symptoms.

Fit-for-Purpose Biometric Monitoring Technologies: Leveraging the Laboratory Biomarker Experience

Biometric monitoring technologies (BioMeTs) are becoming increasingly common to aid data collection in clinical trials and practice. The state of BioMeTs, and associated digitally measured biomarkers, is highly reminiscent of the field of laboratory biomarkers 2 decades ago. In this review, we have summarized and leveraged historical perspectives, and lessons learned from laboratory biomarkers as they apply to BioMeTs. Both categories share common features, including goals and roles in biomedical research, definitions, and many elements of the biomarker qualification framework. They can also be classified based on the underlying technology, each with distinct features and performance characteristics, which require bench and human experimentation testing phases. In contrast to laboratory biomarkers, digitally measured biomarkers require prospective data collection for purposes of analytical validation in human subjects, lack well‐established and widely accepted performance characteristics, require human factor testing, and, for many applications, access to raw (sample‐level) data. Novel methods to handle large volumes of data, as well as security and data rights requirements add to the complexity of this emerging field. Our review highlights the need for a common framework with appropriate vocabulary and standardized approaches to evaluate digitally measured biomarkers, including defining performance characteristics and acceptance criteria. Additionally, the need for human factor testing drives early patient engagement during technology development. Finally, use of BioMeTs requires a relatively high degree of technology literacy among both study participants and healthcare professionals. Transparency of data generation and the need for novel analytical and statistical tools creates opportunities for precompetitive collaborations.

Age and Sex Disparities in Adherence to CPAP

BACKGROUND

CPAP effectiveness is limited by suboptimal adherence. Prior studies of adherence have focused on middle-aged men.

RESEARCH QUESTION

Does CPAP adherence vary by age and sex?

STUDY DESIGN AND METHODS

Telemonitoring data from a CPAP manufacturer database were used to assess adherence in patients initiating CPAP therapy between November 2015 and October 2018. Analyses were restricted to patients in the United States aged 18 to 90 years.

RESULTS

Across 789,260 patients initiated on CPAP (mean age, 55 ± 14 years; 58.2% male), overall adherence by US Centers of Medicare & Medicaid Services criteria was 72.6%, but it varied dramatically by age and sex, ranging from 51.3% in 18- to 30-year-old women to 80.6% in 71- to 80-year-old men. Patterns of use over the first 90 days demonstrated that younger age groups had peak CPAP use by the 2^nd night, with a subsequent decay in use, including abandonment of CPAP, which was greatest among 18- to 30-year-old women. In contrast, older patients steadily increase use, taking more than a week to maximize usage, and then they have much slower decays in use over time. Younger, but not older, patients have lower use of CPAP on weekends compared with weekday nights.

INTERPRETATION

CPAP adherence rates vary substantially by demographics, with 18- to 30-year-old women having the lowest adherence. The pattern of use over the first 90 days also varies substantially by age and sex. Further research to understand and address the causes of disparities will be crucial to maximizing the benefits of CPAP therapy.

0357 CPAP Adherence is Lower in Minority Neighborhoods

Introduction

The effectiveness of continuous positive airway pressure (CPAP) in treating obstructive sleep apnea (OSA) is limited by adherence. Small, single-center studies have reported CPAP adherence is lower in racial minorities suggesting disparities in OSA care. We used nationally representative data to assess racial differences in CPAP adherence at a neighborhood level.

Methods

Telemonitoring data were obtained from a therapy database maintained by a CPAP manufacturer. Usage over the first 90 days in patients initiated on CPAP between 11/01/2015 and 10/31/2018 who had at least one usage session, age 18-90 years, and valid U.S. zip code were mapped to a zip code tabulation area (ZCTA). Age- and sex-adjusted CPAP usage was calculated for each ZCTA with greater than 10 CPAP users. Ecologic analyses were performed to model the association of the proportion of blacks and Hispanics in each ZCTA (obtained from the 2013-2017 American Community Survey) on CPAP usage controlling for proportion of adults with bachelor’s degree and proportion of adults with household income below the poverty line.

Results

Our analysis included 13,118 ZCTAs averaging data over 737,274 patients. In adjusted analyses, each 10% increase in the proportion of blacks and Hispanics was associated with a 0.12 (95% CI 0.11-0.12) hour and 0.14 (95% CI 0.14-0.15) hour decrease in nightly CPAP use, respectively. Mean usage in ZCTAs with &lt;1%, 1-2.5%, 2.5-10%, 10-25%, and 25-100% blacks were 4.96, 4.81, 4.67, 4.56, and 4.14 hours respectively (p&lt;0.001). Mean usage in ZCTAs with &lt;1%, 1-2.5%, 2.5-10%, 10-25%, and 25-100% Hispanics were 4.87, 4.86, 4.75, 4.50, and 4.10 hours respectively (p&lt;0.001).

Conclusion

CPAP adherence is lower in neighborhoods with higher proportions of black and Hispanic residents independent of differences in education or poverty. These differences lead to lower likelihood of meeting insurance coverage requirements for CPAP therapy, potentially exacerbating sleep health disparities.

Support

Philips Respironics, NIH R25HL130600 and K24HL127307.

The role of sham continuous positive airway pressure as a placebo in controlled trials: Best Apnea Interventions for Research Trial

STUDY OBJECTIVES

The main objective of this study was to evaluate the role of sham continuous positive airway pressure (CPAP) compared to conservative medical therapy (CMT) as a control arm in the Best Apnea Interventions for Research (BestAIR) study by assessing differences in subjectively and objectively measured outcomes, adverse events, adherence, and retention rates.

METHODS

BestAIR is a clinical trial aimed to identify important design features for future randomized controlled trials of CPAP. Participants with obstructive sleep apnea were randomized to one of four groups; two control arms (CMT, sham-CPAP) and two active CPAP arms (with and without behavioral interventions). Blood pressure and health-related quality of life outcomes were assessed at baseline, 6 and 12 months. Study outcomes, retention, and adverse event rates were compared between the two control arms. Sham-CPAP adherence and self-efficacy were also compared to active-CPAP adherence (without behavioral intervention).

RESULTS

Our sample included 86 individuals in the control arms and 42 participants in the active-CPAP arm. There were no differences in longitudinal profiles in blood pressure, health-related quality of life outcomes, dropout rates, or adverse events in sham-CPAP group compared to CMT-only group (all ps > 0.05); standardized differences were generally small and with inconsistent directionality across measurements. When compared to active-CPAP, sham-CPAP was associated with 93 fewer minutes/night of usage over 12 months (p = 0.007) and lower outcome expectations (p < 0.05).

CONCLUSION

We observed no evidence of differences in objectively or subjectively measured outcomes with the use of sham-CPAP compared to CMT group. The lower adherence on sham-CPAP and poorer self-efficacy compared to active-CPAP may suggest differences in perceived benefit.

REGISTRATION

NCT01261390 Best Apnea Interventions for Research (BestAIR) www.clinicaltrials.gov.

Verification, analytical validation, and clinical validation (V3): the foundation of determining fit-for-purpose for Biometric Monitoring Technologies (BioMeTs)

Digital medicine is an interdisciplinary field, drawing together stakeholders with expertize in engineering, manufacturing, clinical science, data science, biostatistics, regulatory science, ethics, patient advocacy, and healthcare policy, to name a few. Although this diversity is undoubtedly valuable, it can lead to confusion regarding terminology and best practices. There are many instances, as we detail in this paper, where a single term is used by different groups to mean different things, as well as cases where multiple terms are used to describe essentially the same concept. Our intent is to clarify core terminology and best practices for the evaluation of Biometric Monitoring Technologies (BioMeTs), without unnecessarily introducing new terms. We focus on the evaluation of BioMeTs as fit-for-purpose for use in clinical trials. However, our intent is for this framework to be instructional to all users of digital measurement tools, regardless of setting or intended use. We propose and describe a three-component framework intended to provide a foundational evaluation framework for BioMeTs. This framework includes (1) verification, (2) analytical validation, and (3) clinical validation. We aim for this common vocabulary to enable more effective communication and collaboration, generate a common and meaningful evidence base for BioMeTs, and improve the accessibility of the digital medicine field.

The Effect of Continuous Positive Airway Pressure on Vascular Function and Cardiac Structure in Diabetes and Sleep Apnea. A Randomized Controlled Trial

Rationale: Although both type 2 diabetes mellitus (T2DM) and obstructive sleep apnea (OSA) are independently recognized as risk factors for cardiovascular disease, little is known about their interaction.Objectives: We hypothesized that T2DM and OSA act synergistically to increase vascular risk, and that treatment of OSA would improve vascular reactivity in patients with T2DM plus OSA.Methods: Cross-sectional study of 141 adults with T2DM, OSA, T2DM plus OSA, and control subjects, followed by a 3-month, parallel-arm, randomized, placebo-controlled trial comparing active and sham continuous positive airway pressure (CPAP) in 53 adults with T2DM plus OSA. Endothelium-dependent macro- and microvascular reactivity (flow-mediated dilation [FMD] of the brachial artery and acetylcholine-induced dilation of forearm microvasculature, respectively) and cardiovascular magnetic resonance to assess left- and right-ventricular mass/volume.Results: Mean (±SD) FMD was 6.1 (±4.0)%, 7.3 (±3.6)%, 6.8 (±4.5)%, and 4.8 (±2.9)% in control subjects, T2DM only, OSA only, and T2DM plus OSA, respectively. We observed a significant T2DM × OSA interaction on FMD, such that the mean effect of OSA in those with T2DM was 3.1% (95% confidence interval [CI], 0.6 to 5.6) greater than the effect of OSA in those without T2DM. A total of 3 months of CPAP resulted in a mean absolute increase in FMD of 0.3% (95% CI, -1.9 to 2.5; primary endpoint), with a net improvement of 1.1% (95% CI, -1.4 to 3.6) among those with adherence of 4 h/night or greater. A significant T2DM × OSA interaction was found for both left ventricular (LV) and right ventricular end-diastolic volume, such that OSA was associated with a 22.4 ml (95% CI, 3.2 to 41.6) greater LV end-diastolic volume and 23.2 ml (95% CI, 2.6 to 43.8) greater right ventricular end-diastolic volume in those with T2DM compared with the impact of OSA in those without T2DM. We observed a net improvement in LV end-diastolic volume of 8.7 ml (95% CI, -7.0 to 24.4).Conclusions: The combination of T2DM plus OSA is associated with macrovascular endothelial dysfunction beyond that observed with either disease alone. CPAP for 3 months did not significantly improve macrovascular endothelial function in the intent-to-treat analysis; however, cardiovascular magnetic resonance results suggest that there may be a beneficial effect of CPAP on LV diastolic volume.Clinical trial registered with www.clinicaltrials.gov (NCT01629862).

Pediatric Adenotonsillectomy Trial for Snoring (PATS): protocol for a randomised controlled trial to evaluate the effect of adenotonsillectomy in treating mild obstructive sleep-disordered breathing

INTRODUCTION

Mild obstructive sleep-disordered breathing (oSDB), characterised by habitual snoring without frequent apnoeas and hypopnoeas on polysomnography, is prevalent in children and commonly treated with adenotonsillectomy (AT). However, the absence of high-level evidence addressing the role of AT in improving health and behavioural outcomes has contributed to significant geographical variations in care and potential for surgery to be both overused and underused.

METHODS AND ANALYSIS

The Pediatric Adenotonsillectomy Trial for Snoring (PATS) is a single-blinded, multicentre randomised controlled trial designed to evaluate the effect of AT in treating mild oSDB. Four hundred sixty eligible children, aged 3.0-12.9 years old, will be randomised to either early adenotonsillectomy or to watchful waiting with supportive care (WWSC) with a 1:1 ratio. The study's coprimary endpoints are (1) change from baseline in executive behaviour relating to self-regulation and organisation skills as measured by the Behavioural Rating Inventory of Executive Function (BRIEF) Global Composite Score (GEC); and (2) change from baseline in vigilance as measured on the Go-No-Go (GNG) signal detection parameter (d-prime). A mixed effects model will be used to compare changes in the BRIEF GEC score and GNG score at 6 and 12 months from baseline between the AT arm and the WWSC arm.

ETHICS AND DISSEMINATION

The study protocol was approved by the institutional review board (IRB) at Children's Hospital of Philadelphia (CHOP) on 3 October 2014 (14-0 11 214). The approval of CHOP as the central IRB of record was granted on 29 February 2016. The results will be published in peer-reviewed journals and presented at academic conferences. The data collected from the PATS study will be deposited in a repository (National Sleep Research Resource, sleepdata.org) after completion of the study to maximise use by the scientific community.

TRIAL REGISTRATION NUMBER

NCT02562040; Pre-results.

Advancing the Use of Mobile Technologies in Clinical Trials: Recommendations from the Clinical Trials Transformation Initiative

Mobile technologies offer the potential to reduce the costs of conducting clinical trials by collecting high-quality information on health outcomes in real-world settings that are relevant to patients and clinicians. However, widespread use of mobile technologies in clinical trials has been impeded by their perceived challenges. To advance solutions to these challenges, the Clinical Trials Transformation Initiative (CTTI) has issued best practices and realistic approaches that clinical trial sponsors can now use. These include CTTI recommendations on technology selection; data collection, analysis, and interpretation; data management; protocol design and execution; and US Food and Drug Administration submission and inspection. The scientific principles underpinning the clinical trials enterprise continue to apply to studies using mobile technologies. These recommendations provide a framework for including mobile technologies in clinical trials that can lead to more efficient assessment of new therapies for patients.

A Qualitative Assessment of the Acceptability of Smartphone Applications for Improving Sleep Behaviors in Low-Income and Minority Adolescents

Background: Daily behaviors such as sleep can be targeted by smartphone app-based interventions, with potential utility among young people of minority ethnic backgrounds who commonly access smartphone devices and are short sleepers. There is a need to understand the acceptability and youth's readiness to use apps to improve sleep, and to identify desired app components that would motivate engagement. Participants and Methods: We conducted three focus group discussions (N = 27 total, age 14-18 years) within low- and middle-income ethnically diverse Boston neighborhoods. We also interviewed 10 participants who provided specific feedback on two commercially available sleep-promoting apps, one of which they had used on their smartphone preceding the interviews. All focus group discussions and interviews were audio-recorded, transcribed, and thematically analyzed. Results: We identified several barriers to adoption of sleep hygiene interventions, namely reluctance to follow scheduled sleep routines on weekends and concern about "parting" with electronics at bedtime. Participants were intrigued by the idea of adopting an app-based sleep intervention, but were skeptical that they could successfully adopt sleep hygiene practices, and were more interested in making changes on school days than on weekends. Nonetheless, the overall feedback on two commercial sleep apps, neither targeted at youth, was positive, with a good adherence and engagement rate, and perceived health benefits. Conclusions: Our findings highlight the need to adapt sleep hygiene recommendations to targeted populations, considering preferences and social and cultural contextual factors. Our research also underscores the importance of the platform, setting, and messenger when delivering health information to adolescents.

A systematic review of feasibility studies promoting the use of mobile technologies in clinical research

Mobile technologies, such as smart phone applications, wearables, ingestibles, and implantables, are increasingly used in clinical research to capture study endpoints. On behalf of the Clinical Trials Transformation Initiative, we aimed to conduct a systematic scoping review and compile a database summarizing pilot studies addressing mobile technology sensor performance, algorithm development, software performance, and/or operational feasibility, in order to provide a resource for guiding decisions about which technology is most suitable for a particular trial. Our systematic search identified 275 publications meeting inclusion criteria. From these papers, we extracted data including the medical condition, concept of interest captured by the mobile technology, outcomes captured by the digital measurement, and details regarding the sensors, algorithms, and study sample. Sixty-seven percent of the technologies identified were wearable sensors, with the remainder including tablets, smartphones, implanted sensors, and cameras. We noted substantial variability in terms of reporting completeness and terminology used. The data have been compiled into an online database maintained by the Clinical Trials Transformation Initiative that can be filtered and searched electronically, enabling a user to find information most relevant to their work. Our long-term goal is to maintain and update the online database, in order to promote standardization of methods and reporting, encourage collaboration, and avoid redundant studies, thereby contributing to the design and implementation of efficient, high-quality trials.

Patient satisfaction with sleep study experience: findings from the Sleep Apnea Patient-Centered Outcomes Network

Study Objectives

Home sleep apnea testing (HSAT) is increasingly used as an alternative to laboratory-based polysomnography (PSG) for the diagnosis of obstructive sleep apnea. Patient satisfaction with sleep testing performed at home or in the lab has been sparsely assessed, despite its potentially pivotal role in determining patients' acceptance of sleep apnea treatment. We hypothesize that satisfaction in clinical practice may differ from what has been previously reported within the research setting.

Methods

We analyzed survey data including responses to questions regarding diagnostic sleep study type and sleep study experience satisfaction from 2563 sleep apnea patients enrolled in the Sleep Apnea Patient-Centered Outcomes Network.

Results

Patients (mean age 57 years; 54% male) who underwent in-lab PSG were more likely to be satisfied with their study experience than patients who had a HSAT (71% vs 60%; p < 0.01). Furthermore, the 38 per cent diminished odds of satisfaction in patients having HSAT (OR: 0.62; 95% CI: 0.49-0.77) persisted after adjustment for potential confounders (OR: 0.41, 95% CI; 0.27-0.63). Greater sleep apnea symptom burden and satisfaction with CPAP therapy were associated with greater study satisfaction. Effect modifications on study types by college degree education and tiredness as a study trigger were detected.

Conclusions

Patients receiving care in the community who underwent PSG reported greater satisfaction with study experience than patients who underwent HSAT in contrast to findings from randomized controlled trials. Our findings, based on data from contemporary "real-world" settings, suggest that assumptions about the generalizability of early reports comparing in-lab PSG to home-based paradigms need to be revisited.

Predictors of Continuous Positive Airway Pressure Adherence in Patients with Obstructive Sleep Apnea

Obstructive sleep apnea (OSA) is a common disease which impacts quality of life, mood, cardiovascular morbidity, and mortality. Continuous positive airway pressure (CPAP) is the first-line treatment for patients with moderate to severe OSA. CPAP ameliorates respiratory disturbances, leading to improvements in daytime sleepiness, quality of life, blood pressure, and cognition. However, despite the high efficacy of this device, CPAP adherence is often sub-optimal. Factors including: socio-demographic/economic characteristics, disease severity, psychological factors, and side-effects are thought to affect CPAP adherence in OSA patients. Intervention studies have suggested that augmented support/education, behavioral therapy, telemedicine and technological interventions may improve CPAP adherence. In this paper, we will extensively review the most common factors including age, gender, race/ethnicity, socioeconomic status, smoking status, severity of OSA, severity of OSA symptoms, psychological variables, social support, marital status/bed partner involvement, dry nose and mouth, mask leak, and nasal congestion that may predict CPAP adherence. We will also extensively review interventions that may increase adherence to CPAP.

"Let's talk about sleep": a qualitative examination of levers for promoting healthy sleep among sleep-deprived vulnerable adolescents

OBJECTIVE

Deficient sleep is highly prevalent in disadvantaged adolescents and contributes to a range of adverse health and behavioral outcomes. We examined mediating mechanisms and strategies that adolescents adopt to improve sleep, and possible levers for promoting sleep in this population.

METHODS

We conducted three focus groups (N = 27 total, age 14-18 years) in adolescents living in low- and middle-income racially/ethnically diverse neighborhoods of Boston, Massachusetts. Participants completed a survey on their sleep and health habits prior to the moderator-led discussions. Discussions were audio-recorded, transcribed, and thematically analyzed.

RESULTS

The study population did not meet the minimum sleep recommendations, and we found a high prevalence of "social jet-lag." We also identified a disconnect between the acknowledgment of the importance of sleep and actual behavior, especially for electronic use. Phone use and screen time were the most commonly cited barriers to a good night's sleep, along with caffeine consumption, which was also high in this sample. There was also a general lack of awareness of sleep hygiene practices and recommendations. Participants reported regulating food intake and physical activity, using allopathic sleep aids, creating a comfortable sleeping environment, and a routine as some strategies to improve sleep.

CONCLUSION

Results from this study suggest facilitating the linkage between participant-generated mediating factors and strategies for better-designed interventions. These include making the negative impact of sleep on health more explicit, improving youth awareness about sleep hygiene, targeting caffeine consumption and electronic use, and introducing sleep recommendations through appropriate and effective channels.

The effectiveness of an obstructive sleep apnea screening and treatment program in patients with type 2 diabetes

AIMS

As recommended by current guidelines, we tested the acceptability and impact of screening patients with type 2 diabetes for obstructive sleep apnea (OSA).

METHODS

In a large urban primary care practice, we instituted a telephone-based OSA screening program using a validated tool (STOP-BANG) in patients with type 2 diabetes. Patients identified as high risk were referred for diagnostic sleep testing, and those diagnosed with OSA were offered positive airway pressure (PAP) therapy. We evaluated the impact of PAP on sleep-related symptoms, glycemic control, and hospitalization rates.

RESULTS

We identified 738 of 818 (90.1%) patients with type 2 diabetes as high risk for OSA. Only 29.2% (n = 213) of high risk patients were willing to undergo diagnostic sleep testing. The prevalence of OSA was 90.6% in this group, but only 66.0% of those with OSA initiated PAP. Patients with higher burden of sleep symptoms were more likely to pursue testing and initiate therapy. PAP use was associated with reduced sleep-related symptoms (mean Epworth sleepiness scale score declined from 8.8 to 7.3, p < .001), but did not impact hemoglobin A1c levels at one year (7.7-7.9%, p = .12). Changes in glycemic control and hospitalization rates did not differ from comparator groups.

CONCLUSIONS

Despite a high prevalence of OSA, willingness to pursue diagnostic testing and treatment was low in an unselected type 2 diabetes population. Furthermore, glycemic control did not improve. Future screening programs should focus on patients with substantial sleep related symptoms as this group is most likely to derive benefit from treatment.

Patient Partnerships Transforming Sleep Medicine Research and Clinical Care: Perspectives from the Sleep Apnea Patient-Centered Outcomes Network

ABSTRACT

Due to an ongoing recent evolution in practice, sleep medicine as a discipline has been compelled to respond to the converging pressures to reduce costs, improve outcomes, and demonstrate value. Patient "researchers" are uniquely placed to participate in initiatives that address the specific needs and priorities of patients and facilitate the identification of interventions with high likelihood of acceptance by the "customer." To date, however, the "patient voice" largely has been lacking in processes affecting relevant policies and practice guidelines. In this Special Report, patient and research leaders of the Sleep Apnea Patient-Centered Outcomes Network (SAPCON), a national collaborative group of patients, researchers and clinicians working together to promote patient-centered comparative effectiveness research, discuss these interrelated challenges in the context of sleep apnea, and the role patients and patient-centered networks may play in informing evidence-based research designed to meet patient's needs. We first briefly discuss the challenges facing sleep medicine associated with costs, outcomes, and value. We then discuss the key role patients and patient-centered networks can play in efforts to design research to guide better sleep health care, and national support for such initiatives. Finally, we summarize some of the challenges in moving to a new paradigm of patient-researcher-clinician partnerships. By forging strong partnerships among patients, clinicians and researchers, networks such as SAPCON can serve as a living demonstration of how to achieve value in health care.

Obstructive Sleep Apnea and Vascular Diseases

Obstructive sleep apnea (OSA) affects a large proportion of adults, and is as an independent risk factor for cerebrovascular and cardiovascular disease. The repetitive airway obstruction that characterizes OSA results in intermittent hypoxia, intrathoracic pressure swings, and sleep fragmentation, which in turn lead to sympathetic activation, oxidative stress, inflammation, and endothelial dysfunction. This review outlines the associations between OSA and vascular diseases and describes basic mechanisms that may be responsible for this association, in both the micro- and macrocirculation. It also reports on interventional studies that aim to ameliorate OSA and thereby reduce vascular disease burden. © 2016 American Physiological Society. Compr Physiol 6:1519-1528, 2016.

Motivational Enhancement for Increasing Adherence to CPAP: A Randomized Controlled Trial

BACKGROUND

Motivational enhancement (ME) shows promise as a means of increasing adherence to CPAP for OSA.

METHODS

We performed an open-label, parallel-arm, randomized controlled trial of CPAP only or CPAP + ME, recruiting individuals 45 to 75 years with moderate or severe OSA without marked sleepiness and with either established cardiovascular disease (CVD) or at risk for CVD. All participants received standardized CPAP support from a sleep technologist; those randomly assigned to CPAP + ME also received standardized ME delivered by a psychologist during two appointments and six phone calls over 32 weeks. Mixed-effect models with subject-specific intercepts and slopes were fitted to compare objective CPAP adherence between arms, adjusting for follow-up duration, randomization factors, and device manufacturer. All analyses were intention-to-treat.

RESULTS

Overall, 83 participants (n = 42 CPAP only; n = 41 CPAP + ME) contributed 14,273 nights of data for 6 months. Participants were predominantly male (67%) and had a mean ± SD age of 63.9 ± 7.4 years, a BMI of 31.1 ± 5.2 kg/m(2), and an apnea-hypopnea index of 26.2 ± 12.9 events/h. In our fully adjusted model, average nightly adherence for 6 months was 99.0 min/night higher with CPAP + ME compared with CPAP only (P = .003; primary analysis). A subset of 52 participants remained in the study for 12 months; modeling these data yielded a consistent difference in adherence between arms of 97 min/night (P = .006) favoring CPAP + ME.

CONCLUSIONS

ME delivered during brief appointments and phone calls resulted in a clinically significant increase in CPAP adherence. This strategy may represent a feasible approach for optimizing management of OSA.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT01261390; URL: www.clinicaltrials.gov.

Associations between Obstructive Sleep Apnea, Sleep Duration, and Abnormal Fasting Glucose. The Multi-Ethnic Study of Atherosclerosis

RATIONALE

No data exist as to the role of ethnicity in the associations between obstructive sleep apnea (OSA), sleep duration, and metabolic dysfunction.

OBJECTIVES

To examine links between OSA, objectively measured habitual sleep duration, and fasting glucose in U.S. ethnic groups.

METHODS

The Multi-Ethnic Study of Atherosclerosis is a multisite community-based study that conducted polysomnography and wrist actigraphy. In 2,151 subjects (1,839 in fully adjusted models), the apnea-hypopnea index was used to classify OSA as none (0-4.9/h), mild (5-14.9/h), or moderate to severe (≥15/h). Actigraphic sleep duration was classified as short (≤5 h/night), intermediate (>5 and <8 h/night), or long (≥8 h/night). Subjects were classified as having normal fasting glucose (<100 mg/dl and no hypoglycemic medication use) or abnormal fasting glucose (≥100 mg/dl and/or hypoglycemic medication use).

MEASUREMENTS AND MAIN RESULTS

The sample was 45.8% male, age 68.5 ± 9.2 (mean ± SD) years, and 27.3% African American, 37.2% white, 11.8% Chinese, and 23.8% Hispanic. The prevalence of abnormal fasting glucose was 40.2%. Relative to subjects without apnea, moderate-to-severe OSA was significantly associated with abnormal fasting glucose in African Americans (odds ratio, 2.14; 95% confidence interval, 1.12-4.08) and white participants (odds ratio, 2.85; 95% confidence interval, 1.20-6.75), but not among Chinese or Hispanic subjects, after adjusting for site, age, sex, waist circumference, and sleep duration (P = 0.06 for ethnicity-by-OSA severity interaction). In contrast, sleep duration was not significantly associated with abnormal fasting glucose after considering the influence of OSA.

CONCLUSIONS

This large multiethnic study confirmed previous reports of an independent association between OSA and metabolic dysfunction, and suggested that this association may vary by ethnicity.

Clinical predictors of the respiratory arousal threshold in patients with obstructive sleep apnea

RATIONALE

A low respiratory arousal threshold (ArTH) is one of several traits involved in obstructive sleep apnea pathogenesis and may be a therapeutic target; however, there is no simple way to identify patients without invasive measurements.

OBJECTIVES

To determine the physiologic determinates of the ArTH and develop a clinical tool that can identify patients with low ArTH.

METHODS

Anthropometric data were collected in 146 participants who underwent overnight polysomnography with an epiglottic catheter to measure the ArTH (nadir epiglottic pressure before arousal). The ArTH was measured from up to 20 non-REM and REM respiratory events selected randomly. Multiple linear regression was used to determine the independent predictors of the ArTH. Logistic regression was used to develop a clinical scoring system.

MEASUREMENTS AND MAIN RESULTS

Nadir oxygen saturation as measured by pulse oximetry, apnea-hypopnea index, and the fraction of events that were hypopneas (Fhypopneas) were independent predictors of the ArTH (r(2) = 0.59; P < 0.001). Using this information, we used receiver operating characteristic analysis and logistic regression to develop a clinical score to predict a low ArTH, which allocated a score of 1 to each criterion that was satisfied: (apnea-hypopnea index, <30 events per hour) + (nadir oxygen saturation as measured by pulse oximetry >82.5%) + (Fhypopneas >58.3%). A score of 2 or above correctly predicted a low arousal threshold in 84.1% of participants with a sensitivity of 80.4% and a specificity of 88.0%, a finding that was confirmed using leave-one-out cross-validation analysis.

CONCLUSIONS

Our results demonstrate that individuals with a low ArTH can be identified from standard, clinically available variables. This finding could facilitate larger interventional studies targeting the ArTH.

Interest in bariatric surgery among obese patients with obstructive sleep apnea

BACKGROUND

Standard obstructive sleep apnea (OSA) therapies are poorly tolerated. Bariatric surgery is a potential alternative but the level of interest in this intervention among OSA patients is unknown.

OBJECTIVES

Determine the proportion of OSA patients who would be interested in bariatric surgery.

SETTING

Sleep clinics, United States.

METHODS

Consecutive adult patients with untreated severe OSA and a body mass index of 35-45 kg/m(2) were approached. Patients at low perioperative risk and no urgent indication for OSA treatment were invited to a separate informational visit about bariatric surgery as primary treatment for OSA.

RESULTS

Of 767 eligible patients, 230 (30.0%) were not at low perioperative risk, 49 (6.4%) had drowsy driving, and 16 (2.1%) had no insurance coverage for bariatric surgery. Of the remaining 482 patients, over one third (35.5%) were interested in bariatric surgery. Surgical interest was 47.2% in women versus 27.6% in men (P<0.01) and 67.3% in diabetics versus 31.0% in nondiabetics (P<0.01). In multivariable adjusted models, female gender (odds ratio 1.89, 95% CI [1.10-3.25]) and diabetes (odds ratio 3.97, 95% CI [1.97-8.01]) remained highly predictive of bariatric surgery interest.

CONCLUSIONS

Nearly two thirds of obese patients with severe OSA are good candidates for bariatric surgery. Among candidates, over one third are interested in this treatment. Interest rates are highest among women and diabetics, indicating that metabolic improvements continue to be a major driver of surgery even in patients with severe OSA. Given patient interest, the role of bariatric surgery should be routinely discussed with obese OSA patients.

Obstructive sleep apnea is associated with impaired exercise capacity: a cross-sectional study

OBJECTIVE

Obstructive sleep apnea (OSA) is associated with increased risk of adverse cardiovascular events. Because cardiopulmonary exercise testing (CPET) aids in prognostic assessment of heart disease, there is rising interest in its utility for cardiovascular risk stratification of patients with OSA. However, the relationship between OSA and exercise capacity is unclear. This study was conducted to test the hypothesis that OSA is associated with impaired exercise capacity.

METHODS

Fifteen subjects with moderate-to-severe OSA (apnea-hypopnea index [AHI] ≥15 events/h) and 19 controls with mild or no OSA (AHI <15 events/h) were enrolled. Subjects underwent standard polysomnography to determine AHI and exclude other sleep disorders. Resting metabolic rate was measured via indirect calorimetry, followed by maximum, symptom-limited CPET. Subjects completed a sleep diary and physical activity questionnaire characterizing behaviors in the week prior to testing.

RESULTS

Percent predicted peak oxygen uptake (V˙O2) was significantly lower in OSA subjects than controls (70.1%±17.5% vs 83.8%±13.9%; p = 0.02). Each 1-unit increase in log-transformed AHI was associated with a decrease in percent predicted peak V˙O2 of 3.20 (95% CI 0.53-5.88; p = 0.02). After adjusting for baseline differences, this association remained significant (p < 0.01). AHI alone explained 16.1% of the variability observed in percent predicted peak V˙O2 (p = 0.02).

CONCLUSIONS

OSA is associated with impaired exercise capacity. Further study is needed to evaluate the utility of CPET for prognostic assessment of patients with OSA.

Continuous positive airway pressure treatment for obstructive sleep apnoea: Maori, Pacific and New Zealand European experiences

INTRODUCTION

Continuous positive airway pressure (CPAP) is an effective treatment of obstructive sleep apnoea (OSA), but can be limited by poor adherence. In New Zealand (NZ), ethnicity has been shown to be a predictor of CPAP adherence. This study aimed to explore Maori , Pacific and NZ European patients' experience of CPAP treatment.

METHODS

Patients identifying as Maori , Pacific, or NZ European ethnicity referred for CPAP treatment for OSA attended separate, 1.5-hour group discussions facilitated by a health care worker of the same ethnic group, using an interview template. Thematic analysis was applied to the discussion transcripts independently by two investigators, following published guidelines.

FINDINGS

Five Maori , five Pacific, and eight NZ Europeans participated (mean age 47, range 30-71 years, mean ± standard deviation CPAP adherence 6.32 ± 1.25 hours/night). Patients in all three groups reported that they had little knowledge of OSA or CPAP prior to treatment initiation. All groups identified barriers to treatment (both at the CPAP initiation phase and long term), reported feelings of being 'overwhelmed' with information during the initial CPAP education session, and discussed the importance of successful role models. Family and friends were generally reported as being supportive of CPAP therapy.

CONCLUSION

The three groups all reported similar initial CPAP experiences, highlighting access barriers to publicly funded assessment and treatment pathways, and sleep health knowledge as key issues. Educational resources to improve access, enable self-management, and increase community awareness of OSA would help overcome some of the issues identified in this study.

T1 measurements for detection of expansion of the myocardial extracellular volume in chronic obstructive pulmonary disease

BACKGROUND

We aimed to assess whether chronic obstructive pulmonary disease (COPD) is associated with expansion of the myocardial extracellular volume (ECV) using T1 measurements.

METHODS

Adult COPD patients Global Initiative for Chronic Obstructive Lung Disease [GOLD] stage 2 or higher and free of known cardiovascular disease were recruited. All study patients underwent measures of pulmonary function, 6-minute walk test, serum measures of inflammation, overnight polysomnography, and a contrast cardiac magnetic resonance study.

RESULTS

Eight patients with COPD were compared with 8 healthy control subjects. The mean predicted forced expiratory volume at 1 second of COPD subjects was 68%. Compared with control subjects, patients had normal left ventricular (LV) and right ventricular size, mass, and function. However, compared with control subjects, the LV remodelling index (median, 0.87; interquartile range [IQR], 0.71-1.14; vs median, 0.62; IQR, 0.60-0.77; P ¼ 0.03) and active left atrial emptying fraction was increased (median, 46; IQR, 41-49; vs median, 38; IQR, 33-43; P ¼ 0.005), and passive left atrial emptying fraction was reduced (median, 24; IQR, 20-30; vs median, 44; IQR, 31-51; P ¼ 0.007). The ECV was increased in patients with COPD (median, 0.32; IQR, 0.05; vs median, 0.27; IQR, 0.05; P = 0.001). The ECV showed a strong positive association with LV remodelling (r = 0.72; P = 0.04) and an inverse association with the 6-minute walk duration (r = -0.79; P = 0.02) and passive left atrial emptying fraction (r = -0.68; P = 0.003).

CONCLUSIONS

Expansion of the ECV, suggestive of diffuse myocardial fibrosis, is present in COPD and is associated with LV remodelling, and reduced left atrial function and exercise capacity.

Pilot study of the effects of bariatric surgery and continuous positive airway pressure treatment on vascular function in obese subjects with obstructive sleep apnoea

BACKGROUND

The mechanisms by which obesity and obstructive sleep apnoea (OSA) may contribute to endothelial dysfunction are unclear.

AIMS

We sought to follow up a sample of obese subjects undergoing either bariatric surgery or continuous positive airway pressure (CPAP) therapy to treat OSA. We hypothesised improved vascular function with both therapeutic approaches, consistent with a reversible OSA effect on the circulation.

METHODS

Twenty-seven obese (BMI ≥30 kg/m(2)) subjects with OSA underwent either bariatric surgery without CPAP (n = 12, median BMI 43.7 kg/m(2) IQR 9.4) or CPAP (n = 15, median BMI 33.8 kg/m(2) IQR 6.6). Polysomnography and vascular testing (flow-mediated dilation of the brachial artery measured with high-resolution ultrasound, endothelium-dependent change in skin blood flow measured with laser Doppler flowmetry, and arterial stiffness measured with applanation tonometry) took place at baseline and after 6 months.

RESULTS

Both groups showed significant improvements in the apnoea-hypopnea index and overnight oxygen saturation. Endothelium-dependent microvascular reactivity was 45.6% (IQR 37.5) at baseline in the CPAP group, which increased to 69.1% (IQR 62.3) post-treatment (P < 0.05). No significant changes were observed in the surgery group, despite significant weight loss (post-surgery BMI 32.7 kg/m2 IQR 8.6 (P < 0.01); no change in BMI was observed in the CPAP group. There were no significant changes in brachial artery flow-mediated dilation in either group.

CONCLUSIONS

This pilot study demonstrates that 6 months of CPAP may be sufficient to improve endothelium-dependent microvascular reactivity, while substantial surgically induced weight loss did not result in improvements. Further research should be directed towards comparative effectiveness trials using these novel surrogate outcomes, as well as hard cardiovascular outcomes.

Blood pressure improvement with continuous positive airway pressure is independent of obstructive sleep apnea severity

STUDY OBJECTIVES

We sought to perform a patient-level meta-analysis using the individual patient data of the trials identified in our previous study-level meta-analysis investigating the effect of positive airway pressure (PAP) treatment for obstructive sleep apnea (OSA) on blood pressure (BP).

DESIGN

Patient-level meta-analysis.

SETTING

N/A.

PARTICIPANTS

968 adult OSA subjects without major comorbidities drawn from eight randomized controlled trials.

INTERVENTIONS

Therapeutic PAP versus non-therapeutic control conditions (sham-PAP, pill placebo or standard care) over at least one week.

MEASUREMENTS AND RESULTS

The mean reductions in BP between PAP and non-therapeutic control arms were -2.27 mm Hg (95% CI -4.01 to -0.54) for systolic BP and -1.78 mm Hg (95% CI -2.99 to -0.58) for diastolic BP. The presence of uncontrolled hypertension at baseline was significantly associated with a reduction in systolic BP of 7.1 mm Hg and diastolic BP of 4.3 mm Hg after controlling for OSA severity (apnea-hypopnea index, Epworth Sleepiness Scale score, PAP level), patient demographics (age, gender, body mass index, use of antihypertensive medication/s), and measures of PAP efficacy (PAP adherence and treatment duration).

CONCLUSIONS

OSA patients with uncontrolled hypertension are likely to gain the largest benefit from PAP in terms of a substantial reduction in BP, even after controlling for disease severity.

Effect of sleep apnea and continuous positive airway pressure on cardiac structure and recurrence of atrial fibrillation

BACKGROUND

Sleep apnea (SA) is associated with an increased risk of atrial fibrillation (AF). We sought to determine the effect of SA on cardiac structure in patients with AF, whether therapy for SA was associated with beneficial cardiac structural remodelling, and whether beneficial cardiac structural remodelling translated into a reduced risk of recurrence of AF after pulmonary venous isolation (PVI).

METHODS AND RESULTS

A consecutive group of 720 patients underwent a cardiac magnetic resonance study before PVI. Patients with SA (n=142, 20%) were more likely to be male, diabetic, and hypertensive and have an increased pulmonary artery pressure, right ventricular volume, atrial dimensions, and left ventricular mass. Treated SA was defined as duration of continuous positive airway pressure therapy of >4 hours per night. Treated SA patients (n=71, 50%) were more likely to have paroxysmal AF, a lower blood pressure, lower ventricular mass, and smaller left atrium. During a follow-up of 42 months, AF recurred in 245 patients. The cumulative incidence of AF recurrence was 51% in patients with SA, 30% in patients without SA, 68% in patients with untreated SA, and 35% in patients with treated SA. In a multivariable model, the presence of SA (hazard ratio 2.79, CI 1.97 to 3.94, P<0.0001) and untreated SA (hazard ratio 1.61, CI 1.35 to 1.92, P<0.0001) were highly associated with AF recurrence.

CONCLUSIONS

Patients with SA have an increased blood pressure, pulmonary artery pressure, right ventricular volume, left atrial size, and left ventricular mass. Therapy with continuous positive airway pressure is associated with lower blood pressure, atrial size, and ventricular mass, and a lower risk of AF recurrence after PVI.

Acoustic pharyngometry measurement of minimal cross-sectional airway area is a significant independent predictor of moderate-to-severe obstructive sleep apnea

STUDY OBJECTIVES

The current gold-standard method of diagnosing obstructive sleep apnea (OSA) is polysomnography, which can be inefficient. We therefore sought to determine a method to triage patients at risk of OSA, without using subjective data, which are prone to mis-reporting. We hypothesized that acoustic pharyngometry in combination with age, gender, and neck circumference would predict the presence of moderate-to-severe OSA.

METHODS

Untreated subjects with suspected OSA were recruited from a local sleep clinic and underwent polysomnography. We also included a control group to verify differences. While seated in an upright position and breathing through the mouth, an acoustic pharyngometer was used to measure the minimal cross-sectional area (MCA) of the upper airway at end-exhalation.

RESULTS

Sixty subjects were recruited (35 males, mean age 42 years, range 21-81 years; apnea-hypopnea index (AHI) 33 ± 30 events/h (mean ± standard deviation), Epworth Sleepiness Scale score 11 ± 6, body mass index 34 ± 8 kg/m(2)). In univariate logistic regression, MCA was a significant predictor of mild-no OSA (AHI < 15). A multivariate logistic regression model including MCA, age, gender, and neck circumference significantly predicted AHI < 15, explaining approximately one-third of the total variance (χ(2)(4) = 37, p < 0.01), with only MCA being a significant independent predictor (adjusted odds ratio 54, standard error 130; p < 0.01).

CONCLUSIONS

These data suggest that independent of age, gender, and neck size, objective anatomical assessment can significantly differentiate those with mild versus moderate-to-severe OSA in a clinical setting, and may have utility as a component in stratifying risk of OSA.

Air leak during CPAP titration as a risk factor for central apnea

OBJECTIVES

Emergence of central sleep apnea has been described in the setting of continuous positive airway pressure (CPAP) initiation. The underlying mechanism is unclear; however, we postulate that air leak washing out anatomical dead space is a contributing factor.

DESIGN

Data were obtained from 310 patients with obstructive sleep apnea (OSA) who underwent either split-night or full-night CPAP titration during January to July of 2009. The majority (n = 245) underwent titration with a nasal mask. Average total leak and maximum total leak were measured at therapeutic CPAP level. Unintentional leak was calculated by subtracting manufacturer-defined intentional leak from maximum leak.

RESULTS

SUBJECTS WERE DIVIDED INTO TWO GROUPS: central apnea index (CAI) during titration < 5/hour and ≥ 5/hour. The groups were similar in terms of gender, age, BMI, and AHI. The CAI < 5 group had a median average leak of 45.5 L/min (IQR 20.8 L/min) versus 51.0 L/min (IQR 21.0 L/min) with CAI ≥ 5 (p = 0.056). Maximum leak was 59.5 L/min (IQR 27.0 L/min) with CAI < 5 and 75.0 L/min (IQR 27.8 L/min) with CAI ≥ 5 (p = 0.003). In the subset of subjects titrated using a nasal mask, median average leak was 42.0 L/min (IQR 17.0) in the CAI < 5 group and 50.0 L/min (IQR 16.8) in the CAI ≥ 5 group (p = 0.001). In the CAI < 5 group, median maximum leak was 57.0 L/min (IQR 23.0) versus 74.5 L/min (IQR 24.3) in the CAI ≥ 5 group (p < 0.001).

CONCLUSIONS

Leak during CPAP titration is associated with the development of acute central apnea; these data may have mechanistic and therapeutic implications for complex apnea.

COMMENTARY

A commentary on this article appears in this issue on page 1193.