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.

A latent-class heteroskedastic hurdle trajectory model: patterns of adherence in obstructive sleep apnea patients on CPAP therapy.

BACKGROUND: Sleep apnea patients on CPAP therapy exhibit differences in how they adhere to the therapy. Previous studies have demonstrated the benefit of describing adherence in terms of discernible longitudinal patterns. However, these analyses have been done on a limited number of patients, and did not properly represent the temporal characteristics and heterogeneity of adherence. METHODS: We illustrate the potential of identifying patterns of adherence with a latent-class heteroskedastic hurdle trajectory approach using generalized additive modeling. The model represents the adherence trajectories on three aspects over time: the daily hurdle of using the therapy, the daily time spent on therapy, and the day-to-day variability. The combination of these three characteristics has not been studied before. RESULTS: Applying the proposed model to a dataset of 10,000 patients in their first three months of therapy resulted in nine adherence groups, among which 49% of patients exhibited a change in adherence over time. The identified group trajectories revealed a non-linear association between the change in the daily hurdle of using the therapy, and the average time on therapy. The largest difference between groups was observed in the patient motivation score. The adherence patterns were also associated with different levels of high residual AHI, and day-to-day variability in leakage. CONCLUSION: The inclusion of the hurdle model and the heteroskedastic model into the mixture model enabled the discovery of additional adherence patterns, and a more descriptive representation of patient behavior over time. Therapy adherence was mostly affected by a lack of attempts over time, suggesting that encouraging these patients to attempt therapy on a daily basis, irrespective of the number of hours used, could drive adherence. We believe the methodology is applicable to other domains of therapy or medication adherence.

A Couples-Oriented Intervention for Positive Airway Pressure Therapy Adherence: A Pilot Study of Obstructive Sleep Apnea Patients and Their Partners.

Background: Partner involvement can influence positive airway pressure (PAP) therapy use among patients with obstructive sleep apnea (OSA). This study assessed the feasibility, acceptability, and preliminary efficacy of a couples-oriented education and support (CES) intervention for PAP adherence. Participants: Thirty newly diagnosed OSA patients and their partners were randomly assigned to one of three groups: an education and support intervention directed at both patient and partner (CES), an education and support intervention directed only at the patient (PES), or usual care (UC). Methods: Feasibility and acceptability were assessed through enrollment and posttreatment program evaluations, respectively. Assessments of sleep quality, daytime sleepiness, and daytime function were obtained from both patients and partners at baseline and 3 months after PAP initiation. Objective PAP adherence was assessed at 1 week, 1 month, and 3 months. Results: Recruitment and attrition data suggest adequate feasibility. All patients and partners in the CES group reported that the intervention was helpful. Patients in the CES and PES groups increased their PAP adherence over the first month of treatment, whereas PAP adherence decreased over this period in the UC group. For patients, large to medium effects for sleep quality (d = -1.01), daytime sleepiness (d = -0.51), and daytime function (d = 0.51) were found for the CES group. The PES and UC groups effect sizes were large to small for sleep quality (d = -0.94; d = -0.40), daytime sleepiness (d = -0.42; d = -0.82), and daytime function (d = 0.41; d = 0.57), respectively. For partners, large effects for daytime sleepiness (d = -1.31) and daytime function (d = 1.54) and small to medium effect for sleep quality (d = -0.31) were found for the CES group. Worsening of sleep quality (d = 0.65) and no change in daytime sleepiness or daytime function were found for the PES group. For the UC group, medium to large effects were found for sleep quality (d = -0.77), daytime sleepiness (d = -0.77), and daytime function (d = 0.65). Conclusions: The findings of this pilot study provide support for taking a couples intervention approach to improve PAP adherence.

Patient and Partner Experiences With Obstructive Sleep Apnea and CPAP Treatment: A Qualitative Analysis.

Few studies have investigated factors associated with continuous positive airway pressure (CPAP) treatment for sleep apnea from the patients' and their partners' perspective. This qualitative research study explored patients' and partners' experiences of CPAP and facilitators and barriers to CPAP use, and elicited suggestions for a first-time CPAP user program. Data from 27 participants were collected via four sleep apnea patient and four partner focus groups. Qualitative content analysis identified five themes: knowledge of sleep apnea, effects of sleep apnea, effects of CPAP, barriers and facilitators of CPAP, and ideas for a new user support program. Patients and partners emphasized the importance of partner involvement in the early CPAP treatment period. These data suggest consideration of a couple-oriented approach to improving CPAP adherence.

Identifying Longitudinal Patterns for Individuals and Subgroups: An Example with Adherence to Treatment for Obstructive Sleep Apnea.

To improve complex behaviors such as adherence to medical recommendations, a better understanding of behavior change over time is needed. The focus of this study was adherence to treatment for obstructive sleep apnea (OSA). Adherence to the most common treatment for OSA is poor. This study involved a sample of 161 participants, each with approximately 180 nights of data. First, a time series analysis was performed for each individual. Time series parameters included the mean (average hours of use per night), level, slope, variance, and autocorrelation. Second, a dynamic cluster analysis was performed to find homogenous subgroups of individuals with similar adherence patterns. A four-cluster solution was found, and the subgroups were labeled: Great Users (17.2%; high mean and level, no slope), Good Users (32.8%; moderate mean and level, no slope), Low Users (22.7%; low mean and level, negative slope), and Slow Decliners (moderate mean and level, negative slope, high variance). Third, participants in the identified subgroups were compared to establish external validity. These steps represent a Typology of Temporal Patterns (TTP) approach. Combining time series analysis and dynamic cluster analysis is a useful way to evaluate longitudinal patterns at both the individual level and subgroup level.

The impact of cannabis use proximal to sleep and cannabinoid metabolites on sleep architecture.

STUDY OBJECTIVES: Cannabis is a common sleep aid, however the effects of its use prior to sleep are poorly understood. This study aims to determine the impact of non-medical whole plant cannabis use three hours prior to sleep and measured cannabis metabolites on polysomnogram measures. METHODS: This is a cross-sectional study of 177 healthy adults who provided detailed cannabis use history, underwent a one-night home sleep test (HST) and had measurement of eleven plasma and urinary cannabinoids, quantified using mass spectroscopy, the morning after the HST. Multivariable models were used to assess the relationship between cannabis use proximal to sleep, which was defined as use three hours before sleep, and individual HST measurements. Correlation between metabolite concentrations and polysomnogram measures were assessed. RESULTS: In adjusted models, cannabis use proximal to sleep was associated with increased wake after sleep onset (median 60.5 versus 45.8 minutes), rate ratio 1.59 (1.22, 2.05), and increased proportion of stage one sleep (median 15.2% versus 12.3%), effect estimate 0.16 (0.06, 0.25). Compared to non-users, frequent cannabis users (>20 days per month) also had increased wake after sleep onset and stage one sleep, in addition to increased REM latency and decreased percent sleep efficiency. Delta-9 tetrahydrocannabinol metabolites correlated with these HST measures. CONCLUSIONS: Cannabis use proximal to sleep was associated with minimal changes in sleep architecture. Its use wasn't associated with measures of improved sleep including increased sleep time or efficiency and may be associated with poor quality sleep through increase wake onset and stage 1 sleep.

Observational study to understand the effect of timing and regularity on sleep metrics and cardiorespiratory parameters using data from a smart bed.

Sleep regularity and chronotype can affect health, performance, and overall well-being. This observational study examines how sleep regularity and chronotype affect sleep quality and cardiorespiratory metrics. Data was collected from 1 January 2019 through 30 December 2019 from over 330 000 Sleep Number smart bed users across the United States who opted into this at-home study. A pressure signal from the smart bed reflected bed presence, movements, heart rate (HR), and breathing rate (BR). Participants (mean age: 55.69 years [SD: 14.0]; 51.2% female) were categorized by chronotype (16.8% early; 62.2% intermediate, 20.9% late) and regularity of sleep timing. Participants who were regular sleepers (66.1%) experienced higher percent restful sleep and lower mean HR and BR compared to the 4.8% categorized as irregular sleepers. Regular early-chronotype participants displayed better sleep and cardiorespiratory parameters compared to those with regular late-chronotypes. Significant variations were noted in sleep duration (Cohen's d = 1.54 and 0.88, respectively) and restful sleep (Cohen's d = 1.46 and 0.82, respectively) between early and late chronotypes, particularly within regular and irregular sleep patterns. This study highlights how sleep regularity and chronotype influence sleep quality and cardiorespiratory metrics. Irrespective of chronotype, sleep regularity demonstrated a substantial effect. Further research is necessary to confirm these findings.

Fine tuned personalized machine learning models to detect insomnia risk based on data from a smart bed platform.

Introduction: Insomnia causes serious adverse health effects and is estimated to affect 10-30% of the worldwide population. This study leverages personalized fine-tuned machine learning algorithms to detect insomnia risk based on questionnaire and longitudinal objective sleep data collected by a smart bed platform. Methods: Users of the Sleep Number smart bed were invited to participate in an IRB approved study which required them to respond to four questionnaires (which included the Insomnia Severity Index; ISI) administered 6 weeks apart from each other in the period from November 2021 to March 2022. For 1,489 participants who completed at least 3 questionnaires, objective data (which includes sleep/wake and cardio-respiratory metrics) collected by the platform were queried for analysis. An incremental, passive-aggressive machine learning model was used to detect insomnia risk which was defined by the ISI exceeding a given threshold. Three ISI thresholds (8, 10, and 15) were considered. The incremental model is advantageous because it allows personalized fine-tuning by adding individual training data to a generic model. Results: The generic model, without personalizing, resulted in an area under the receiving-operating curve (AUC) of about 0.5 for each ISI threshold. The personalized fine-tuning with the data of just five sleep sessions from the individual for whom the model is being personalized resulted in AUCs exceeding 0.8 for all ISI thresholds. Interestingly, no further AUC enhancements resulted by adding personalized data exceeding ten sessions. Discussion: These are encouraging results motivating further investigation into the application of personalized fine tuning machine learning to detect insomnia risk based on longitudinal sleep data and the extension of this paradigm to sleep medicine.

Obstructive sleep apnea: impact of hypoxemia on memory.

PURPOSE: Attempts to understand the causes of cognitive impairment in obstructive sleep apnea (OSA) are complicated by the overlap among clinical and demographic factors that may impact cognition. The goal of the current study was to isolate the contribution of hypoxemia to cognitive impairment in OSA. METHODS: Two groups of 20 patients with newly diagnosed OSA were compared. The groups differed on severity of hypoxemia but not other demographic (e.g., age, gender, education, estimated premorbid IQ) or clinical (e.g., sleep related respiratory disturbances, daytime sleepiness, depressive symptoms) variables. Participants completed polysonmography and cognitive assessment. RESULTS: We compared patients with high and low hypoxemia on measures of memory, attention, executive functioning, and motor coordination using independent sample t-tests. The high hypoxemia group performed significantly better on immediate recall (Hopkins Verbal Learning Test - Revised; t = -2.50, p < 0.02) than the low hypoxemia group. No group differences were observed on other neuropsychological measures. CONCLUSIONS: This study is one of the first to compare the cognitive performance of patients with high and low hypoxemia after controlling for demographic factors and aspects of OSA severity that could confound the relationship. In our carefully matched sample, we observed an unexpected advantage of higher hypoxemia on memory. These preliminary findings are discussed in the context of basic science literature on the protective effects of adaptation to intermittent hypoxemia. Our data suggest that the association between hypoxemia and cognition may not straightforward. Future research targeting the effects of hypoxemia on cognition controlling for other clinical factors in large groups of patients with OSA will be important.

Sleep-disordered breathing and cognition in older adults.

Both sleep-disordered breathing (SDB) and cognitive impairment are common among older adults, yet few studies have examined their relationship within this population to determine whether the effect of SDB on cognition is of a magnitude similar to or greater than that observed in younger and middle-aged adults. Here, we review the extant literature and report that studies are largely supportive of an association between SDB and cognitive impairment in older adults, particularly in the domains of attention/vigilance, executive function, and verbal delayed recall memory. Presence of the APOE4 allele may confer increased vulnerability to SDB-associated cognitive dysfunction among elderly individuals. Although findings are mixed, there is strong evidence to suggest that SDB-related intermittent hypoxemia is the primary mechanism through which SDB exerts its adverse effects on cognition. We propose a microvascular model in which chronic intermittent hypoxemia causes vasculopathy that ultimately is expressed as cognitive impairment in the older adult. However, it remains unclear whether the effects of SDB on cognition are the same regardless of age or whether there is a synergistic interaction between age and SDB.

Obstructive sleep apnea: brain structural changes and neurocognitive function before and after treatment.

RATIONALE: Obstructive sleep apnea (OSA) is commonly associated with neurocognitive impairments that have not been consistently related to specific brain structure abnormalities. Knowledge of the brain structures involved in OSA and the corresponding functional implications could provide clues to the pathogenesis of cognitive impairment and its reversibility in this disorder. OBJECTIVES: To investigate the cognitive deficits and the corresponding brain morphology changes in OSA, and the modifications after treatment, using combined neuropsychologic testing and voxel-based morphometry. METHODS: A total of 17 patients treatment-naive to sleep apnea and 15 age-matched healthy control subjects underwent a sleep study, cognitive tests, and magnetic resonance imaging. After 3 months of treatment, cognitive and imaging data were collected to assess therapy efficacy. MEASUREMENTS AND MAIN RESULTS: Neuropsychologic results in pretreatment OSA showed impairments in most cognitive areas, and in mood and sleepiness. These impairments were associated with focal reductions of gray-matter volume in the left hippocampus (entorhinal cortex), left posterior parietal cortex, and right superior frontal gyrus. After treatment, we observed significant improvements involving memory, attention, and executive-functioning that paralleled gray-matter volume increases in hippocampal and frontal structures. CONCLUSIONS: The cognitive and structural deficits in OSA may be secondary to sleep deprivation and repetitive nocturnal intermittent hypoxemia. These negative effects may be recovered by consistent and thorough treatment. Our findings highlight the importance of early diagnosis and successful treatment of this disorder.

Adherence to cognitive behavioral therapy for insomnia (CBTI) among women following primary breast cancer treatment: a pilot study.

Cognitive behavioral therapy for insomnia (CBTI) has proven efficacy, yet 32%-89% of patients fail to consistently follow recommendations. This pilot study examines adherence to CBTI in breast cancer survivors with insomnia. There was a significant decline in adherence to prescribed rise time, and total time in bed, but no change in adherence to prescribed bedtime during six weekly sessions. Factors associated with higher adherence included lower fatigue and higher baseline motivation. Higher adherence was associated with worse subjective sleep quality at the beginning of CBTI and fewer nocturnal awakenings at the end of treatment. Results provide preliminary evidence supporting the impact of adherence on sleep outcomes such as fewer nocturnal awakenings. Attention to adherence as part of CBTI may yield greater sleep improvements.

Impact of an Extended Telemonitoring and Coaching Program on Continuous Positive Airway Pressure Adherence.

Rationale: The benefits of continuous positive airway pressure (CPAP) therapy in obstructive sleep apnea are limited by adherence. Telemonitoring and coaching have been demonstrated to increase adherence, but the ideal duration of such support is unclear. Objectives: To compare the impact of a 12-month versus a 3-month behavioral support program on CPAP adherence. Methods: We evaluated real-world CPAP adherence data from all patients initiating CPAP between July 1, 2018, and April 1, 2020, by any durable medical equipment (DME) providers who had used a 12-month commercially available telemonitoring/coaching program (Long Term Adherence Management, Philips Respironics) in this timeframe. Patients receiving either 12 months or 3 months of support (Patient Adherence Management Service) were compared with those initiated on CPAP without support. Mean CPAP adherence was computed monthly over the initial 18 months. Missing usage was imputed as zero use. All analyses were adjusted for age, sex, and DME provider. Results: The nine DME providers using the 12-month telemonitoring/coaching service cared for a total of 26,489 patients (3,264 receiving 12-month support, 15,424 receiving 3-month support, and 7,801 receiving no support) in the timeframe under study. In adjusted analyses, mean CPAP use in the 3-month support group was greater than the no support group in Month 3 (4.6 h vs. 4.3 h; P < 0.001) but subsequently, usage declined to match the no support group at both Month 12 and Month 18. In contrast, mean CPAP use was greater in the 12-month support group than in the no support group at Month 3 (4.6 h vs. 4.3 h; P < 0.001), Month 12 (4.0 h vs. 3.6 h; P < 0.001), and Month 18 (3.3 h vs. 3.2 h; P = 0.02). Conclusions: A 3-month telemonitoring/coaching program increases CPAP use in the short term but does not lead to sustained improvements. In contrast, a 12-month program leads to sustained improvements but results still diminish once coaching ceases. Implementation of longer-term telemonitoring and coaching programs may be vital to obtaining long-term benefits from CPAP therapy.

Improving sleep apnea treatment adherence after traumatic brain injury: A nonrandomized feasibility study.

PURPOSE/OBJECTIVE: To evaluate the feasibility of a psychological intervention designed to increase Positive Airway Pressure (PAP) adherence, adapted with cognitive accommodations for comorbid obstructive sleep apnea (OSA) and traumatic brain injury (TBI). RESEARCH METHOD/DESIGN: This was an open-label single arm (nonrandomized) study. Eligibility criteria were moderate-to-severe TBI, OSA diagnosis, prescribed PAP, nonadherent, and able to consent. Participants were recruited from inpatient and outpatient settings at a tertiary care hospital. The four-module manualized intervention was delivered primarily via telehealth. Feasibility aspects measured included eligibility, recruitment, and retention rates; session duration and attendance; and characteristics of outcome and process measures (e.g., completion rates, data distribution). Symptom measures included the Epworth Sleepiness Scale, Fatigue Severity Scale, Functional Outcomes of Sleep Questionnaire, Self-Efficacy Measure for Sleep Apnea, OSA Treatment Barriers Questionnaire (OTBQ), and Kim Alliance Scale-Revised. RESULTS: Of 230 persons screened, 14.3% were eligible. Recruitment rate (n = 17) was 51.5%. Retention rate (n = 13) was 76.5%. Treatment completers had no missing data. The OTBQ deviated from normality, but other measures had adequate skew (< 2.0) and kurtosis (< 7.0) and were free from significant floor and ceiling effects (<15%). Change score effect sizes were minimal to moderate (d = .10-.77). There were no adverse events. CONCLUSIONS/IMPLICATIONS: These results inform ways in which procedures should be modified to enhance the success of a future clinical trial testing the efficacy of this adherence intervention. Inclusion criteria should be reconsidered, and recruitment sites expanded, to capture eligible persons and adequately power an efficacy study. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

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 2nd 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.

Obstructive sleep apnea and early weight loss among adolescents undergoing bariatric surgery.

BACKGROUND: Little is known regarding obstructive sleep apnea's (OSA's) prevalence or the factors related to OSA remission post-metabolic bariatric surgery (MBS) in adolescents. OBJECTIVES: To identify the baseline OSA prevalence in adolescents with severe obesity and examine factors associated with post-MBS OSA remission. SETTING: Tertiary-care children's hospital. METHODS: We conducted a retrospective chart review of 81 patients pre-MBS with OSA assessments done between June 2017 to September 2020 to collect demographic characteristics; co-morbidities; polysomnography (PSG) results, if indicated; and weight data. Chi-square or Mann-Whitney tests compared baseline characteristics and surgical outcomes by pre-MBS OSA status. McNemar's test or t tests assessed differences in baseline characteristics, stratified by remission versus no remission of OSA. RESULTS: The patients were 71% female, had an average age of 16.9 ± 2.0 years, and had a mean body mass index (BMI) of 47.9 ± 7.3 kg/m2. Half (50%) of the patients were Hispanic and 20% had type 2 diabetes. The OSA prevalence, defined as an Obstructive Apnea Hypopnea Index (OAHI) score ≥5, was 54% pre-MBS (n = 44), with 43% having severe OSA (OAHI > 30). Those with OSA were older (17.3 versus 16.4 yr, respectively; P = .05), more likely to be male (79% versus 42%, respectively; P = .022), and had higher baseline weights (142.0 versus 126.4 kg, respectively; P = .001) than those without OSA. Of the 23 patients with a post-MBS PSG result (average 5 mo post MBS), 15 (66%) had remission of OSA. Patients with OSA remission had a lower average pre-MBS BMI (46.0 versus 57.7 kg/m2, respectively; P < .001) and weight (132.9 versus 172.6 kg, respectively; P = .002) but no significant differences in percentage weight loss through 12 months post MBS versus those with continued OSA. CONCLUSION: The OSA prevalence in an adolescent MBS population was higher than that in the general adolescent population with severe obesity. Remission of OSA was correlated with lower pre-MBS BMI and weight, but not weight loss within the first year post-MBS.

Cognitive performance is lower among individuals with overlap syndrome than in individuals with COPD or obstructive sleep apnea alone: association with carotid artery stiffness.

Chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) are both independently associated with increased cardiovascular disease (CVD) risk and impaired cognitive function. It is unknown if individuals with both COPD and OSA (i.e., overlap syndrome) have greater common carotid artery (CCA) stiffness, an independent predictor of CVD risk, and lower cognitive performance than either COPD or OSA alone. Elevated CCA stiffness is associated with cognitive impairment in former smokers with and without COPD in past studies. We compared CCA stiffness and cognitive performance between former smokers with overlap syndrome, COPD only, OSA only and former smoker controls using analysis of covariance (ANCOVA) tests to adjust for age, sex, body mass index (BMI), pack years, and postbronchodilator FEV1/FVC. We also examined the association between CCA stiffness and cognitive performance among each group separately. Individuals with overlap syndrome (n = 12) had greater CCA ß-stiffness index (P = 0.015) and lower executive function-processing speed (P = 0.019) than individuals with COPD alone (n = 47), OSA alone (n = 9), and former smoker controls (n = 21), differences that remained significant after adjusting for age, BMI, sex, pack years, and FEV1/FVC. Higher CCA ß-stiffness index was associated with lower executive function-processing speed in individuals with overlap syndrome (r = -0.58, P = 0.047). These data suggest that CCA stiffness is greater and cognitive performance is lower among individuals with overlap syndrome compared with individuals with COPD or OSA alone and that CCA stiffening may be an underlying mechanism contributing to the lower cognitive performance observed in patients with overlap syndrome.NEW & NOTEWORTHY Previous studies have demonstrated greater carotid artery stiffness and lower cognitive function among individuals with COPD alone and OSA alone. However, the present study is the first to demonstrate that individuals that have both COPD and OSA (i.e., overlap syndrome) have greater carotid artery stiffness and lower executive function-processing speed than individuals with either disorder alone. Furthermore, among individuals with overlap syndrome greater carotid artery stiffness is associated with lower executive function-processing speed.

A telemedicine intervention to improve adherence to continuous positive airway pressure: a randomised controlled trial.

BACKGROUND: Continuous positive airway pressure (CPAP) is the most widely prescribed treatment for obstructive sleep apnoea syndrome (OSAS). Although it has been shown to improve the symptoms of OSAS, many patients have difficulty adhering to this treatment. The purpose of this study was to investigate the effectiveness of an automated telemedicine intervention to improve adherence to CPAP. METHODS: A randomised clinical trial was undertaken in 250 patients being started on CPAP therapy for OSAS. Patients were randomly assigned to use a theory-driven interactive voice response system designed to improve CPAP adherence (telephone-linked communications for CPAP (TLC-CPAP), n=124) or to an attention placebo control (n=126) for 12 months. TLC-CPAP monitors patients' self-reported behaviour and CPAP-related symptoms and provides feedback and counselling through a structured dialogue to enhance motivation to use CPAP. A Sleep Symptoms Checklist, the Functional Outcomes of Sleep Questionnaire, the Center for Epidemiological Studies Depression Scale and the Psychomotor Vigilance Task were administered at study entry and at 6-month and 12-month follow-up. Hours of CPAP usage at effective mask pressure were measured by the CPAP device stored in its memory and retrieved at each visit. RESULTS: Median observed CPAP use in patients randomised to TLC-CPAP was approximately 1 h/night higher than in the control subjects at 6 months and 2 h/night higher at 12 months. Using generalised estimating equation modelling, the intervention had a significant effect on CPAP adherence. For secondary analysis, the effect of CPAP adherence on the secondary outcomes was analysed. CPAP adherence was significantly associated with a greater reduction in sleep apnoea symptoms and depressive symptoms and a greater improvement in functional status. No significant association was observed between CPAP adherence and reaction time. CONCLUSIONS: The TLC-CPAP intervention resulted in improved CPAP adherence, which was associated with improved functional status and fewer depressive symptoms. CLINICAL TRIAL.GOV: NCT00232544.

Randomizing research participants: promoting balance and concealment in small samples.

Randomization is central to rigorous scientific trials. An effective but underutilized approach is urn randomization. To test the ability of urn randomization versus simple randomization to produce balanced groups with small sample sizes, we conducted simulated randomizations: 10 times under sample size scenarios of 20, 40, 60 (group sizes of 10, 20, and 30, respectively), for 30 trials in total. For groups of 20-30, urn surpassed simple randomization in the equal distribution of confounding variables between groups, leading to effects of these variables that were both smaller on average and more consistently close to zero over multiple trials. The urn method is easy to implement and has the advantages of unpredictability of assignment and decreased susceptibility to investigator bias.