Impact of wait times for treatment on clinical outcomes in patients with obstructive sleep apnoea: protocol for a randomised controlled trial.

Background: Obstructive sleep apnoea (OSA) is a common chronic condition that is associated with significant morbidity and economic cost. Prolonged wait times are increasingly being recognised as a barrier to diagnosis and treatment of many chronic diseases; however, no study to date has prospectively evaluated the impact of wait times on health outcomes in OSA. Objective: The purpose of this study is to determine whether treatment outcomes for individuals with OSA differ between patients managed using an expedited versus standard pathway. Methods: A pragmatic randomised controlled trial design will be used with a target sample size of 200 adults. Participants with clinically significant uncomplicated OSA will be recruited through referrals to a large tertiary care sleep centre (Calgary, AB, Canada) and randomised to either early management (within 1 month) or usual care (∼6 months) with a 1:1 allocation using a concealed computer-generated randomisation sequence. The primary outcome will be adherence to positive airway pressure (PAP) therapy at 3 months after treatment initiation. Secondary outcomes will include change in sleepiness, quality of life, patient satisfaction, and patient engagement with therapy from baseline to 3 months after PAP initiation, measured using validated questionnaires and qualitative methods. Anticipated results: This study will determine whether expedited care for OSA leads to differences in PAP adherence and/or patient-reported outcomes. More broadly, the findings of this study may improve the understanding of how wait time reductions impact health outcomes for other chronic diseases.

Treatment outcomes among rural and urban patients with obstructive sleep apnea: a prospective cohort study.

STUDY OBJECTIVES: To determine whether adherence to continuous positive airway pressure (CPAP) in adults with uncomplicated obstructive sleep apnea differs by rural vs urban residential address. METHODS: In this prospective cohort study, we recruited adults who initiated CPAP for uncomplicated obstructive sleep apnea that was diagnosed by a physician using sleep specialist-interpreted diagnostic testing. Participants were classified as urban (community size > 100,000) or rural (community size < 100,000) by translating residential postal code into geographic census area. The primary outcome was mean daily hours of CPAP use compared between rural and urban patients. Secondary outcomes included the proportion of patients who were adherent to CPAP, change in Epworth Sleepiness Scale score, change in EuroQOL-5D visual analog score, and Visit-Specific Satisfaction Instrument score. All outcomes were measured 3 months after CPAP initiation. RESULTS: We enrolled 242 patients (100 rural) with a mean (standard deviation) age of 51 (13) years and a respiratory event index of 24 (18) events/h. The mean (95% confidence interval) CPAP use was 3.19 (2.8-3.58) hours/night and 35% were CPAP-adherent, with no difference between urban and rural patients. Among the 65% of patients who were using CPAP at 3 months, the mean CPAP use was 4.89 (4.51-5.28) hours/night and was not different between rural and urban patients. Improvement in the Epworth Sleepiness Scale score and patient satisfaction was similar between groups, but the EuroQOL-5D score improved to a greater extent in rural patients. Urban or rural residence was not associated with CPAP adherence according to multivariable regression analysis. CONCLUSIONS: Rural vs urban residence was not associated with differences in CPAP adherence among patients with uncomplicated OSA diagnosed by a physician using specialist-interpreted sleep diagnostic testing. CITATION: Corrigan J, Tsai WH, Ip-Buting A, et al. Treatment outcomes among rural and urban patients with obstructive sleep apnea: a prospective cohort study. J Clin Sleep Med. 2022;18(4):1013-1020.

Perspectives on primary care management of obstructive sleep apnea: a qualitative study of patients and health care providers.

STUDY OBJECTIVES: Difficulties in providing timely access to care have prompted interest in primary care delivery models for obstructive sleep apnea (OSA). Sustainable implementation of such models requires codesign with input from key stakeholders. The purpose of this study was to identify patient and provider perspectives on barriers and facilitators to optimal, patient-centered management of OSA in a primary care setting. METHODS: This study was conducted in Alberta, Canada. Data from key stakeholders were collected through an online survey of primary care providers (n = 119), focus groups and interviews with patients living with OSA (n = 28), and workshops with primary care and sleep providers (n = 36). Quantitative survey data were reported using descriptive statistics, and qualitative data were analyzed using an inductive thematic approach. RESULTS: Several barriers were identified, including poor specialist access, variable primary care providers knowledge of OSA, and lack of clarity about provider roles for OSA management. Barriers contributed to patients being poorly informed about OSA, leading them to separate OSA from their overall health and eroding trust in the system. Suggestions for improvement included integration of care providers in a comprehensive model of care, facilitated by improved system navigation and more effective use of technology. Themes were consistent across data collection methods and between stakeholder groups. CONCLUSIONS: Although primary care delivery models may improve access to OSA management, stakeholders identified important challenges in the current system. Innovative models of care, developed with input from patients and providers, may mitigate barriers and support optimal primary care management of OSA.

An evaluation of rural-urban disparities in treatment outcomes for obstructive sleep apnoea: study protocol for a prospective cohort study.

BACKGROUND: Obstructive sleep apnoea (OSA) is a common and treatable chronic condition that is associated with significant morbidity and economic cost. Geography is increasingly being recognised as a barrier to diagnosis and treatment of many chronic diseases; however, no study to date has investigated the impact of place of residence on health outcomes in OSA. OBJECTIVE: The purpose of this study is to determine whether treatment outcomes for patients initiating continuous positive airway pressure (CPAP) for OSA differ between those who live in urban versus rural settings. METHODS: A prospective cohort design will be used. Participants will be recruited through community-based CPAP providers and assigned to either the rural or urban cohort based on residential postal code. The primary outcome will be the difference in nightly hours of CPAP use between the two groups, measured 3 months after initiation of therapy. Secondary outcomes will include symptoms, quality of life, patient satisfaction and patient-borne costs. ANTICIPATED RESULTS: This study will determine whether there are differences in CPAP adherence or patient-reported outcomes between rural and urban patients with OSA. These results will highlight potential challenges with providing OSA care in rural populations and may inform health interventions to reduce urban-rural inequities.

Predicting CPAP failure in patients with suspected sleep hypoventilation identified on ambulatory testing.

STUDY OBJECTIVES: Home sleep apnea testing (HSAT) is commonly used to diagnose obstructive sleep apnea, but its role in identifying patients with suspected hypoventilation or predicting their response to continuous positive airway pressure (CPAP) therapy has not been assessed. The primary objective was to determine if HSAT, combined with clinical variables, could predict the failure of CPAP to correct nocturnal hypoxemia during polysomnography in a population with suspected hypoventilation. Secondary objectives were to determine if HSAT and clinical parameters could predict awake or sleep hypoventilation. METHODS: A retrospective review was performed of 142 consecutive patients who underwent split-night polysomnography for suspected hypoventilation after clinical assessment by a sleep physician and review of HSAT. We collected quantitative indices of nocturnal hypoxemia, patient demographics, medications, pulmonary function tests, as well as arterial blood gas data from the night of the polysomnography . CPAP failure was defined as persistent obstructive sleep apnea, hypoxemia (oxygen saturation measured by pulse oximetry < 85%), or hypercapnia despite maximal CPAP. RESULTS: Failure of CPAP was predicted by awake oxygen saturation and arterial blood gas results but not by HSAT indices of nocturnal hypoxemia. Awake oxygen saturation ≥ 94% ruled out CPAP failure, and partial pressure of oxygen measured by arterial blood gas ≥ 68 mmHg decreased the likelihood of CPAP failure significantly. CONCLUSIONS: In patients with suspected hypoventilation based on clinical review and HSAT interpretation by a sleep physician, awake oxygen saturation measured by pulse oximetry and partial pressure of oxygen measured by arterial blood gas can reliably identify patients in whom CPAP is likely to fail. Additional research is required to determine the role of HSAT in the identification and treatment of patients with hypoventilation.

Effects of Wait Times on Treatment Adherence and Clinical Outcomes in Patients With Severe Sleep-Disordered Breathing: A Secondary Analysis of a Noninferiority Randomized Clinical Trial.

Importance: Sleep-disordered breathing (SDB) is common and associated with substantial adverse health consequences. Long wait times for SDB care are commonly reported; however, it is unclear whether wait times for care are associated with clinical outcomes. Objective: To evaluate the association of wait times for care with clinical outcomes for patients with severe SDB. Design, Setting, and Participants: This study is a secondary analysis of a randomized clinical noninferiority trial comparing management by alternative care practitioners (ACPs) with traditional sleep physician-led care between October 2014 and May 2017. The study took place at Foothills Medical Centre Sleep Centre, a tertiary care multidisciplinary sleep clinic at the University of Calgary. Patients with severe SDB (defined as a respiratory event index ≥30 events per hour during home sleep apnea testing, mean nocturnal oxygen saturation ≤85%, or suspected sleep hypoventilation syndrome) were recruited for the study. Patients were excluded if they were suspected of having a concomitant sleep disorder other than SDB or had previously been treated with positive airway pressure (PAP) therapy for SDB. Data were analyzed from October 2017 to January 2020. Main Outcomes and Measures: Outcomes were assessed 3 months after treatment initiation with adherence to PAP therapy as the primary outcome. Secondary outcomes included Epworth Sleepiness Scale score, health-related quality of life, and patient satisfaction measured using the Visit-Specific Satisfaction Instrument-9. Multiple regression models were used to assess the associations between wait times and each of the outcomes. t tests were used to compare wait times for patients who were adherent to PAP therapy (≥4 hours per night for 70% of nights) with those for nonadherent patients. Results: One hundred fifty-six patients (112 [71.8%] men; mean [SD] age, 56 [12] years) were included in the analysis. The mean time from referral to initial visit was 88 days (95% CI, 79 to 96 days), and the mean time to treatment was 123 days (95% CI, 112 to 133 days). Shorter wait time to treatment initiation was associated with adherence to PAP therapy (odds ratio, 0.99; 95% CI, 0.98 to 0.99; P = .04), greater improvement in Epworth Sleepiness Scale score (mean coefficient, -9.37; 95% CI, -18.51 to -0.24; P = .04), and higher Visit-Specific Satisfaction Instrument-9 score (mean coefficient, -0.024; 95% CI, -0.047 to -0.0015; P = .04) at 3 months. Compared with nonadherent patients, those who were adherent to treatment waited a mean of 15 fewer days (95% CI, 12 to 19 days) for initial assessment (P = .07) and 30 fewer days (95% CI, 23 to 35 days) for treatment initiation (P = .008). Conclusions and Relevance: Earlier initiation of treatment for severe SDB was associated with better PAP adherence and greater improvements in daytime sleepiness and patient satisfaction. These findings suggest that system interventions to improve timely access may modify patient behavior and improve clinical outcomes. Trial Registration: ClinicalTrials.gov Identifier: NCT02191085.

Functional-Optical Coherence Tomography: A Non-invasive Approach to Assess the Sympathetic Nervous System and Intrinsic Vascular Regulation.

Sympathetic nervous system dysregulation and vascular impairment in neuronal tissue beds are hallmarks of prominent cardiorespiratory diseases. However, an accurate and convenient method of assessing SNA and local vascular regulation is lacking, hindering routine clinical and research assessments. To address this, we investigated whether spectral domain optical coherence tomography (OCT), that allows investigation of retina and choroid vascular responsiveness, reflects sympathetic activity in order to develop a quick, easy and non-invasive sympathetic index. Here, we compare choroid and retina vascular perfusion density (VPD) acquired with OCT and heart rate variability (HRV) to microneurography. We recruited 6 healthy males (26 ± 3 years) and 5 healthy females (23 ± 1 year) and instrumented them for respiratory parameters, ECG, blood pressure and muscle sympathetic nerve microneurography. Choroid VPD decreases with the cold pressor test, inhaled hypoxia and breath-hold, and increases with hyperoxia and hyperpnea suggesting that sympathetic activity dominates choroid responses. In contrast, retina VPD was unaffected by the cold pressor test, increased with hypoxia and breath hold and decreases with hyperoxia and hyperpnea, suggesting metabolic vascular regulation dominates the retina. With regards to integrated muscle sympathetic nerve activity, HRV had low predictive power whereas choroid VPD was strongly (inversely) correlated with integrated muscle sympathetic nerve activity (R = -0.76; p < 0.0001). These data suggest that Functional-OCT may provide a novel approach to assess sympathetic activity and intrinsic vascular responsiveness (i.e., autoregulation). Given that sympathetic nervous system activity is the main determinant of autonomic function, sympathetic excitation is associated with severe cardiovascular/cardiorespiratory diseases and autoregulation is critical for brain health, we suggest that the use of our new Functional-OCT technique will be of broad interest to clinicians and researchers.

A Randomized Controlled Trial of an Alternative Care Provider Clinic for Severe Sleep-disordered Breathing.

Rationale: Lack of timely access to diagnosis and treatment of sleep-disordered breathing (SDB) has sparked interest in using nonphysician providers. Previous studies of these alternative care providers (ACPs) excluded patients with more complicated forms of SDB and did not directly explore the impacts of a model incorporating ACPs on healthcare system performance, such as wait times.Objectives: To evaluate the use of ACPs in the management of patients with severe SDB from a clinical and system perspective.Methods: In this noninferiority study, patients with severe SDB (N = 156) were enrolled from October 2014 to July 2016 and randomized to either sleep physician management or management by ACP with same-day sleep physician review. Severe SDB was defined as one of 1) respiratory event index greater than 30/h, 2) mean nocturnal oxygen saturation less than 85%, and 3) arterial carbon dioxide greater than 45 mm Hg with respiratory event index greater than 15/h. The primary outcome was nightly positive airway pressure adherence at 3 months, using a noninferiority margin of 1 hour. Secondary outcomes included sleepiness, quality of life, patient satisfaction, wait times for diagnosis and treatment initiation, and demand for further testing and clinical assessment. Outcomes were evaluated using modified intention-to-treat and per-protocol analyses.Results: Care delivery using ACPs was indeterminate compared with sleep physician care with respect to treatment adherence, because the 95% confidence interval included the noninferiority margin of 1 hour (mean difference, -0.5 [-1.49 to 0.49] h). Patients in the ACP arm reported greater improvements in sleepiness and quality of life; wait times were shorter for initial assessment (28%) and treatment initiation (18%). There was no difference in demand for sleep testing or clinical follow-up. Per-protocol analysis revealed similar results.Conclusions: Management of severe SDB using ACPs was indeterminate compared with sleep physician care. The small decrease in adherence in the ACP arm was balanced by benefits in patient-reported outcomes and reduction in wait times. In systems with unacceptably long wait times for SDB diagnosis and treatment, a small decrease in treatment adherence, as was observed in this study, may be an acceptable trade-off to improve access to care for patients with severe SDB.Clinical trial registered with www.clinicaltrials.gov (NCT02191085).

Evaluation of an alternative care provider clinic for severe sleep-disordered breathing: a study protocol for a randomised controlled trial.

INTRODUCTION: Despite the high prevalence of sleep-disordered breathing (SDB) and the significant health consequences associated with untreated disease, access to diagnosis and treatment remains a challenge. Even patients with severe SDB (severe obstructive sleep apnoea or hypoventilation), who are at particularly high risk of adverse health effects, are subject to long delays. Previous research has demonstrated that, within a sleep clinic, management by alternative care providers (ACPs) is effective for patients with milder forms of SDB. The purpose of this study is to compare an ACP-led clinic (ACP Clinic) for patients with severe SDB to physician-led care, from the perspective of clinical outcomes, health system efficiency and cost. METHODS AND ANALYSIS: The study is a randomised, controlled, non-inferiority study in which patients who are referred with severe SDB are randomised to management by a sleep physician or by an ACP. ACPs will be supervised by sleep physicians for safety. The primary outcome is positive airway pressure (PAP) adherence after 3 months of therapy. Secondary outcomes include: long-term PAP adherence; clinical response to therapy; health-related quality of life; patient satisfaction; healthcare usage; wait times from referral to treatment initiation and cost-effectiveness. The economic analysis will be performed using the perspective of a publicly funded healthcare system. ETHICS AND DISSEMINATION: Ethics approval was obtained from the Conjoint Health Research Ethics Board (ID: REB13-1280) at the University of Calgary. Results from this study will be disseminated through presentations at scientific conferences and publication in peer-reviewed journals. TRIAL REGISTRATION NUMBER: NCT02191085; Pre-results.

Validity of administrative data for identification of obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a common condition associated with significant morbidity and health-care utilization. We determined the validity of an algorithm derived from administrative data for identifying OSA using the respiratory disturbance index (RDI) as the reference standard. We conducted a retrospective cohort study of adults in Alberta, Canada referred for facility and community-based sleep diagnostic testing between July 2005 and August 2007. Validity indices were estimated for several case definitions of OSA derived from outpatient physician billing claims and hospital discharge codes. For each algorithm, the sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were calculated against several reference standards for OSA (RDI ≥ 5 h-1 , RDI ≥ 15 h-1 or RDI ≥ 30 h-1 ). For the 2149 patients included in the study, an algorithm requiring one hospital discharge code or two outpatient billing claims identifying OSA in a 2-year period had a sensitivity of 24.1%, specificity of 67.8%, PPV of 74.8% and NPV of 18.3% (reference standard RDI ≥ 5 h-1 ). When comorbidities were included in the case definition, the specificity was 90.5% and PPV was 83.3% (reference standard RDI ≥ 5 h-1 ). Similar findings were observed using RDI ≥ 15 h-1 and ≥30 h-1 as the reference standard. We identify a claims-based algorithm that identifies OSA with a high degree of specificity in patients referred for sleep diagnostic testing. This validated algorithm has a good PPV and may be useful when identifying patients with OSA for population studies within a single-payer health-care system.

Birt-Hogg-Dubé syndrome: a large single family cohort.

BACKGROUND: Birt-Hogg-Dubé (BHD) syndrome is an autosomal dominant condition characterized by dermatologic lesions, pulmonary manifestations, and renal tumors. The syndrome arises from germline mutations in the folliculin (FLCN) gene. We present findings from the single largest family BHD cohort described to date. Primary objectives were to characterize cystic lung changes on computed tomography (CT) chest scanning and identify features that stratify patients at higher risk of pneumothorax. Secondary objectives entailed description of the following: type and natural history of BHD-associated pneumothorax, pulmonary function characteristics, and relationship between cystic lung changes and pulmonary function. METHODS: The study was a retrospective chart review for a case series of a single family. Over 70 family members of a proband with documented BHD were identified, 68 of which consented to genetic testing. All those with confirmed BHD were offered a clinical assessment by the Medical Genetics and Pulmonary services which included a history, physical exam, complete pulmonary function tests, and computed tomography (CT) scan of the chest and abdomen. RESULTS: Thirty-six individuals had a heterozygous mutation in the FLCN gene (c.59delT). Of these, 100 % (28/28) had pulmonary cysts, 41 % (13/32) had spontaneous pneumothoraces, 26 % (8/31) had kidney cysts, 3 % (1/31) had renal tumors, and 53 % (18/34) had dermatologic manifestations. Recurrent pneumothoraces were common (40 %). Cyst size (OR 3.23, 95 % CI 1.35-7.73) and extent of lower lung zone disease (OR 6.43, 95 % CI 1.41-29.2) were the only findings associated with pneumothorax. The size or extent of cystic disease did not correlate with lung function results. CONCLUSIONS: This is the largest single family cohort of patients with BHD syndrome documented to date. We found that all individuals had pulmonary cysts, pneumothoraces were common, and cyst size and lower lobe predominant disease were associated with pneumothorax. Lung function was generally preserved and not affected by a high cyst burden.

Healthcare Use in Individuals with Obesity and Chronic Hypoxemia Treated for Sleep Disordered Breathing.

STUDY OBJECTIVES: To determine if treatment of obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS) among patients with chronic hypoxemia is associated with reduced healthcare utilization. METHODS: We performed a retrospective cohort study of 129 obese, hypoxemic patients who underwent polysomnography and were prescribed positive airway pressure (PAP) therapy. During a 2-year follow-up period we examined the associations between adherence to PAP therapy and rates of hospitalization, emergency room (ER) visits, and outpatient visits. RESULTS: Severe OSA and OHS were common, as were hypertension, cardiovascular, and pulmonary disease. Forty-nine percent of patients were adherent with PAP therapy. Compared to patients who were not adherent to PAP therapy, adherent patients had significantly lower rates of all-cause hospitalization (incident rate ratio [IRR]:0.55, 95% CI 0.33, 0.93) after adjustment for age, sex and hospitalisation rates prior to treatment. Adjustment for additional comorbidities attenuated this association (IRR: 0.61, 95% CI 0.35, 1.06). Adherence with PAP therapy was associated with lower odds of frequent hospitalization (odds ratio 0.23, 95% CI 0.07, 0.73). There were no significant differences in the rates of ER or outpatient visits between adherent and non-adherent patients. CONCLUSIONS: Adherence with PAP treatment in patients with chronic hypoxemia and chronic medical disorders is associated with reduced rates of hospitalization, which has significant benefit both for patients and the healthcare system.

An observational study of the effectiveness of alternative care providers in the management of obstructive sleep apnea.

Alternative care providers have been proposed as a substitute for physician-based management of obstructive sleep apnea. The purpose of this study was to describe the clinical course of patients with a new diagnosis of obstructive sleep apnea who were treated with continuous positive airway pressure and followed by alternative care providers at a tertiary care sleep clinic. It was hypothesized that care by alternative care providers would result in improvement of daytime sleepiness and satisfactory treatment adherence, and that a specific number of follow-up visits could be identified after which clinical outcomes no longer improved. The Epworth Sleepiness Scale score was measured for each patient at baseline and at each alternative care provider visit. Patients were discharged when they demonstrated a significant improvement in sleepiness and were adherent to therapy. The Epworth Sleepiness Scale score decreased by 3.9 points from baseline to discharge. Patients with three or more visits required more follow-up time to achieve the same clinical improvement as those with only two visits. Continuous positive airway pressure adherence was comparable to previous studies of physician-led care and improved with ongoing alternative care provider follow-up. The current results suggest that clinical care by alternative care providers leads to continued improvements in sleepiness in patients with obstructive sleep apnea who are treated with continuous positive airway pressure, and that a minority of patients require longer follow-up to achieve a satisfactory clinical response to therapy.

Treatment of Sleep Disordered Breathing Liberates Obese Hypoxemic Patients from Oxygen.

BACKGROUND: Obese hypoxemic patients have a high prevalence of sleep disordered breathing (SDB). It is unclear to what extent treatment of SDB can improve daytime hypoxemia. METHODS: We performed a retrospective cohort study of obese hypoxemic individuals, all of whom underwent polysomnography, arterial blood gas analysis, and subsequent initiation of positive airway pressure (PAP) therapy for SDB. Patients were followed for one year for change in partial pressure of arterial oxygen and the need for supplemental oxygen. RESULTS: One hundred and seventeen patients were treated with nocturnal PAP and had follow-up available. Adherence to PAP was satisfactory in 60%, and was associated with a significant improvement in daytime hypoxemia and hypercapnea; 56% of these patients were able to discontinue supplemental oxygen. Adherence to PAP therapy and the baseline severity of OSA predicted improvement in hypoxemia, but only adherence to PAP therapy predicted liberation from supplemental oxygen. CONCLUSIONS: The identification and treatment of SDB in obese hypoxemic patients improves daytime hypoxemia. It is important to identify SDB in these patients, since supplemental oxygen can frequently be discontinued following treatment with PAP therapy.

Flow-volume loop abnormality detecting a previously unrecognized right upper lobe tracheal bronchus.

Tracheal bronchus is a rare anatomic variant in which a bronchus originates from the trachea. Patients may be asymptomatic or present with a variety of respiratory symptoms. We present a case of a patient who presented with a history of poorly controlled asthma and a persistent abnormality of the flow-volume loop. Bronchoscopy revealed a tracheal bronchus with narrowed right-sided bronchial orifices. An unrecognized tracheal bronchus may result in serious complications during elective or emergent endotracheal intubation. Spirometry testing may reveal abnormalities of the flow-volume loop associated with altered airflow. Relying on spirometric values without assessing the shape of the flow-volume loop may lead to misdiagnosis and inappropriate management of lung pathology.

Use of electronic data and existing screening tools to identify clinically significant obstructive sleep apnea.

OBJECTIVES: To assess the ability of electronic health data and existing screening tools to identify clinically significant obstructive sleep apnea (OSA), as defined by symptomatic or severe OSA. METHODS: The present retrospective cohort study of 1041 patients referred for sleep diagnostic testing was undertaken at a tertiary sleep centre in Calgary, Alberta. A diagnosis of clinically significant OSA or an alternative sleep diagnosis was assigned to each patient through blinded independent chart review by two sleep physicians. Predictive variables were identified from online questionnaire data, and diagnostic algorithms were developed. The performance of electronically derived algorithms for identifying patients with clinically significant OSA was determined. Diagnostic performance of these algorithms was compared with versions of the STOP-Bang questionnaire and adjusted neck circumference score (ANC) derived from electronic data. RESULTS: Electronic questionnaire data were highly sensitive (>95%) at identifying clinically significant OSA, but not specific. Sleep diagnostic testing-determined respiratory disturbance index was very specific (specificity ≥95%) for clinically relevant disease, but not sensitive (<35%). Derived algorithms had similar accuracy to the STOP-Bang or ANC, but required fewer questions and calculations. CONCLUSIONS: These data suggest that a two-step process using a small number of clinical variables (maximizing sensitivity) and objective diagnostic testing (maximizing specificity) is required to identify clinically significant OSA. When used in an online setting, simple algorithms can identify clinically relevant OSA with similar performance to existing decision rules such as the STOP-Bang or ANC.

Prevalence of Sleep-disordered Breathing in Obese Patients with Chronic Hypoxemia. A Cross-Sectional Study.

RATIONALE: Hypoxemia in obese patients is likely to be associated with a high prevalence of sleep-disordered breathing. Supplemental oxygen is commonly used to treat chronic hypoxemia but carries some risk in obese individuals due to unrecognized comorbid obstructive sleep apnea (OSA) and obesity hypoventilation syndrome (OHS). OBJECTIVES: The first step in the estimation of this risk is to determine the prevalence of OSA and OHS in obese individuals with chronic, awake hypoxemia. METHODS: A single-center retrospective cohort study was performed to assess the prevalence and severity of OSA and OHS among obese individuals with hypoxemia. One hundred eighty-four individuals underwent arterial blood gas testing and polysomnography. One hundred fifty-eight of these individuals also had spirometry. MEASUREMENTS AND MAIN RESULTS: The prevalence of OSA was 80%, and the prevalence of OHS was 51%. Chronic obstructive pulmonary disease (COPD) was confirmed by spirometry in 49% of the cohort, and OSA was found in 69% of those individuals. The severity of hypoxemia in this cohort was not statistically related to COPD, OSA, or OHS. CONCLUSIONS: OSA and OHS are highly prevalent in obese patients with chronic awake hypoxemia, and OSA frequently coexists with COPD. Evaluation of chronic, awake hypoxemia solely based on arterial blood gas measurements and pulmonary function testing is not sufficient to identify OSA and OHS. Further diagnostic sleep testing should be performed to identify those who could benefit from alternative therapies and to avoid potential harm from treatment with supplemental oxygen alone.

Effect of treatment of obstructive sleep apnea on depressive symptoms: systematic review and meta-analysis.

BACKGROUND: Obstructive sleep apnea (OSA) is associated with increased morbidity and mortality, and decreased quality of life. Treatment with continuous positive airway pressure (CPAP) or mandibular advancement devices (MADs) is effective for many symptoms of OSA. However, it remains controversial whether treatment with CPAP or MAD also improves depressive symptoms. METHODS AND FINDINGS: We performed a systematic review and meta-analysis of randomized controlled trials that examined the effect of CPAP or MADs on depressive symptoms in patients with OSA. We searched Medline, EMBASE, the Cochrane Central Registry of Controlled Trials, and PsycINFO from the inception of the databases until August 15, 2014, for relevant articles. In a random effects meta-analysis of 19 identified trials, CPAP treatment resulted in an improvement in depressive symptoms compared to control, but with significant heterogeneity between trials (Q statistic, p<0.001; I(2) = 71.3%, 95% CI: 54%, 82%). CPAP treatment resulted in significantly greater improvement in depressive symptoms in the two trials with a higher burden of depression at baseline (meta-regression, p<0.001). The pooled standardized mean difference (SMD) in depressive symptoms with CPAP treatment in these two trial populations with baseline depression was 2.004 (95% CI: 1.387, 2.621), compared to 0.197 (95% CI: 0.059, 0.334) for 15 trials of populations without depression at baseline. Pooled estimates of the treatment effect of CPAP were greater in parallel arm trials than in crossover trials (meta-regression, p = 0.076). Random effects meta-analysis of five trials of MADs showed a significant improvement in depressive symptoms with MADs versus controls: SMD = 0.214 (95% CI: 0.026, 0.401) without significant heterogeneity (I(2) = 0%, 95% CI: 0%, 79%). Studies were limited by the use of depressive symptom scales that have not been validated specifically in people with OSA. CONCLUSIONS: CPAP and MADs may be useful components of treatment of depressive symptoms in individuals with OSA and depression. The efficacy of CPAP and MADs compared to standard therapies for depression is unknown. Please see later in the article for the Editors' Summary.

Identification of insomnia in a sleep center population using electronic health data sources and the insomnia severity index.

STUDY OBJECTIVES: To assess the validity and efficacy of using electronic health data to identify a physician diagnosis of insomnia in a population of patients referred for testing at a tertiary sleep center. METHODS: Retrospective cohort study in a tertiary sleep center in Calgary, Alberta, Canada. Cohort consisted of 1,207 patients referred for sleep diagnostic testing and/or assessment by a sleep physician. Two sleep physicians independently assigned each patient a primary sleep diagnosis. Univariate logistic regression was used to identify variables that were predictive for insomnia from online questionnaire and diagnostic testing data. Diagnostic algorithms derived from these predictors and from the Insomnia Severity Index were evaluated against physician diagnosis as a reference standard. RESULTS: The combination of self-reported sleep latency > 20 minutes, total sleep time < 6.5 hours per night, the inability to fall asleep after waking, BMI < 27 kg/m(2), and Epworth Sleepiness Scale score < 9 had very high specificity (99.3%) for diagnosing insomnia; however, sensitivity was poor (11.8%). Other algorithms derived from these data had either high sensitivity or high specificity. No combination of variables yielded simultaneous high sensitivity and specificity. Likewise, the Insomnia Severity Index can be highly sensitive or highly specific at identifying insomnia, but not both. CONCLUSIONS: Diagnostic algorithms derived from electronic data can provide high specificity or high sensitivity for identifying insomnia.

Targeted case finding for OSA within the primary care setting.

STUDY OBJECTIVES: The aim was to determine the feasibility of using an unattended 2-channel device to screen for obstructive sleep apnea in a population of high-risk patients using a targeted, case-finding strategy. The case finding was based on the presence of risk factors not symptoms in the studied population. METHODS: The study took place from June 2007 to May 2008 in rural and metropolitan Queensland and New South Wales. Family doctors were asked to identify patients with any of the following: BMI > 30, type 2 diabetes, treated hypertension, ischemic heart disease. Participants applied the ApneaLink+O2 at home for a single night. The device recorded nasal flow and pulse oximetry. Data were analyzed by proprietary software, then checked and reported by either of two sleep physicians. RESULTS: 1,157 patients were recruited; mean age 53 ± 14.6, M/F% = 62/38, mean BMI = 31.8, obesity = 35%, diabetes = 16%, hypertension = 39%, IHD = 5%, Mean Epworth Sleepiness Scale score (ESS) = 8.3. The prevalence of unrecognized OSA was very high: 71% had an AHI > 5/h, 33% had an AHI > 15/h, and 16% had an AHI > 30/h. The ApneaLink+O2 device yielded technically adequate studies in 93% of cases. CONCLUSION: The study shows that a "real world" simple low cost case finding and management program, based on unattended home monitoring for OSA, can work well in a population with risk factors and comorbidities associated with OSA, independent of the presence of symptoms. The prevalence of unrecognized OSA was very high.