Initial use of portable monitoring versus polysomnography to confirm obstructive sleep apnea in symptomatic patients: an economic decision model

Out of the Laboratory and into the Home: Home Testing for Sleep Apnea and Other Sleep Disorders

SUMMARY

Home sleep testing has emerged over the past decade and become an intriguing option for patients and providers because it can be conducted in the home environment. However, appropriate application of this technology is key to ensure accurate and validated results to provide appropriate patient care. In this review, we will cover the current guidelines for the use of home sleep apnea tests, the types of testing available, and future directions of home testing.

In search of a cut-off apnea-hypopnea index in type 3 home portable monitors to diagnose and treat obstructive sleep apnea: a mathematical simulation

The American Academy of Sleep Medicine (AASM) uses similar apnea-hypopnea index (AHI) cut-off values to diagnose and define severity of sleep apnea independent of the technique used: in-hospital polysomnography (PSG) or type 3 portable monitoring (PM). Taking into account that PM theoretically might underestimate the AHI, we explored whether a lower cut-off would be more appropriate. We performed mathematical re-calculations on the diagnostic PSG-AHI (scored using AASM 1999 rules) of 865 consecutive patients with an AHI of ≥20 events/h who started continuous positive airway pressure (CPAP). For a PSG-AHI of ≥15 events/h re-scored using AASM 2012 rules (PSG-AHI^AASM2012 ), a PM-respiratory event index (REI)^AASM2012 cut-off point of ≥15 events/h resulted in a post-test probability of 100% of having the disease, but with negative tests in 57.1%. A PM-REI^AASM2012 cut-off of 8 events/h, still resulted in a positive post-test probability of 100% but with negative tests in only 34.3%. Combination of the cut-off values with clinical estimation of being 'at high risk' based on Epworth Sleepiness Scale (ESS) and Berlin Questionnaire scores only resulted in a small reduction in the percentage of negative tests (respectively 52.7% and 32.7%). After 6 months, CPAP adherence was not lower using the PM-REI^{AASM 2012} cut-off ≥8 events/h in comparison to ≥15 events/h (median 5.7 vs. 5.8 h/night, p = 0.368) and the reduction in ESS was similar too (median -4 and -5 points, p = 0.083). Consequently, using a lower PM-REI^AASM2012 cut-off could result in cost savings because of less negative studies and lesser need for a confirmatory PSG or a performance of a CPAP trial.

Revisiting level II sleep studies in the era of COVID-19: a theoretical economic decision model in patients with suspected obstructive sleep apnea

Background

The recent pandemic has made it more challenging to assess patients with suspected obstructive sleep apnea (OSA) with in laboratory polysomnography (PSG) due to concerns of patient and staff safety. The purpose of this study was to assess how Level II sleep studies (LII, full PSG in the home) might be utilized in diagnostic algorithms of suspected OSA using a theoretical decision model.

Methods

We examined four diagnostic algorithms for suspected OSA: an initial PSG approach, an initial LII approach, an initial Level III approach (LIII, limited channel home sleep study) followed by PSG if needed, and an initial LIII approach followed by LII if needed. Costs per patient assessed was calculated as a function of pretest OSA probability and a variety of other variables (e.g. costs of tests, failure rate of LIII/LII, sensitivity/specificity of LIII). The situation in British Columbia was used as a case study.

Results

The variation in cost per test was calculated for each algorithm as a function of the above variables. For British Columbia, initial LII was the least costly across a broad range of pretest OSA probabilities (< 0.80) while initial LIII followed by LII as needed was least costly at very high pretest probability (> 0.8). In patients with a pretest OSA probability of 0.5, costs per patient for initial PSG, initial LII, initial LIII followed by PSG, and initial LIII followed by LII were: $588, $417, $607, and $481 respectively.

Conclusions

Using a theoretical decision model, we developed a preliminary cost framework to assess the potential role of LII studies in OSA assessment. Across a broad range of patient pretest probabilities, initial LII studies may provide substantial cost advantages. LII studies might be especially useful during pandemics as they combine the extensive physiologic information characteristic of PSG with the ability to avoid in-laboratory stays. More empiric studies need to be done to test these different algorithms.

Supplementary Information

The online version contains supplementary material available at 10.1186/s41606-021-00063-5.

A novel postal-based approach to diagnosing obstructive sleep apnoea in a high-risk population

OBJECTIVE

More than 50% of patients with diabetic macular oedema (DMO) have obstructive sleep apnoea (OSA), but the majority remain undiagnosed. We used a four-channel device (ApneaLink [AL], ResMed, UK) to establish a remote postal-based diagnostic service for patients with DMO. Here we describe our experience.

METHODS

Patients with DMO were invited to participate. Interested patients returned a free-post reply slip to the study team, who posted an AL with pictorial and written instructions to them. Following a single night study, the AL was returned by a freepost service.

RESULTS

Responses from 733 patients meeting the inclusion criteria were received, comprising 469 males and 264 females, mean age 64 years (standard deviation 10.4 years). ALs were issued to 718 patients, of whom 606 completed a diagnostic study. A total of 71 patients (12%) required a repeat study due to inadequacy of the first attempt. Completed sleep studies showed that 75% of respondents had sleep disordered breathing: 4% ODI 0-4/h, 24%; 5-9/h, 19%; 10-19/h, 23%; ≥20/h, 34%; and AHI 0-4/h, 25%; 5-14/h, 38%; 15-29/h, 20%; ≥30/h, 17%. Among 1592 postal events through the national post service, 20 ALs were lost.

CONCLUSIONS

We have demonstrated that a remote postal-based diagnostic service for populations with a high risk of OSA can be successfully performed. This novel approach, which avoids clinic attendance, may be useful in clinical practice.

Accuracy of Automatic Polysomnography Scoring Using Frontal Electrodes

STUDY OBJECTIVES

The economic cost of performing sleep monitoring at home is a major deterrent to adding sleep data during home studies for investigation of sleep apnea and to investigating non-respiratory sleep complaints. Michele Sleep Scoring System (MSS) is a validated automatic system that utilizes central electroencephalography (EEG) derivations and requires minimal editing. We wished to determine if MSS' accuracy is maintained if frontal derivations are used instead. If confirmed, home sleep monitoring would not require home setup or lengthy manual scoring by technologists.

METHODS

One hundred two polysomnograms (PSGs) previously recorded from patients with assorted sleep disorders were scored using MSS once with central and once with frontal derivations. Total sleep time, sleep/stage R sleep onset latencies, awake time, time in different sleep stages, arousal/awakening index and apnea-hypopnea index were compared. In addition, odds ratio product (ORP), a continuous index of sleep depth/quality (Sleep 2015;38:641-54), was generated for every 30-sec epoch in each PSG and epoch-by-epoch comparison of ORP was performed.

RESULTS

Intraclass correlation coefficients (ICCs) ranged from 0.89 to 1.0 for the various sleep variables (0.96 ± 0.03). For epoch-by-epoch comparisons of ORP, ICC was > 0.85 in 96 PSGs. Lower values in the other six PSGs were related to signal artifacts in either derivation. ICC for whole-record average ORP was 0.98.

CONCLUSIONS

MSS is as accurate with frontal as with central EEG derivations. The use of frontal electrodes along with MSS should make it possible to obtain high-quality sleep data without requiring home setup or lengthy scoring time by expert technologists.

Evaluation of a Decision Support System for Obstructive Sleep Apnea with Nonlinear Analysis of Respiratory Signals

Introduction

Obstructive Sleep Apnea (OSA) is a common sleep disorder requiring the time/money consuming polysomnography for diagnosis. Alternative methods for initial evaluation are sought. Our aim was the prediction of Apnea-Hypopnea Index (AHI) in patients potentially suffering from OSA based on nonlinear analysis of respiratory biosignals during sleep, a method that is related to the pathophysiology of the disorder.

Materials and Methods

Patients referred to a Sleep Unit (135) underwent full polysomnography. Three nonlinear indices (Largest Lyapunov Exponent, Detrended Fluctuation Analysis and Approximate Entropy) extracted from two biosignals (airflow from a nasal cannula, thoracic movement) and one linear derived from Oxygen saturation provided input to a data mining application with contemporary classification algorithms for the creation of predictive models for AHI.

Results

A linear regression model presented a correlation coefficient of 0.77 in predicting AHI. With a cutoff value of AHI = 8, the sensitivity and specificity were 93% and 71.4% in discrimination between patients and normal subjects. The decision tree for the discrimination between patients and normal had sensitivity and specificity of 91% and 60%, respectively. Certain obtained nonlinear values correlated significantly with commonly accepted physiological parameters of people suffering from OSA.

Discussion

We developed a predictive model for the presence/severity of OSA using a simple linear equation and additional decision trees with nonlinear features extracted from 3 respiratory recordings. The accuracy of the methodology is high and the findings provide insight to the underlying pathophysiology of the syndrome.

Conclusions

Reliable predictions of OSA are possible using linear and nonlinear indices from only 3 respiratory signals during sleep. The proposed models could lead to a better study of the pathophysiology of OSA and facilitate initial evaluation/follow up of suspected patients OSA utilizing a practical low cost methodology.

Trial Registration

ClinicalTrials.gov NCT01161381

Portable Monitoring for the Diagnosis of OSA

In-laboratory, attended polysomnography has long been the gold standard for the diagnosis of sleep-disordered breathing (SDB). In recent years, economic pressures and long wait times have driven interest in home sleep testing, which has, in turn, led to the development of algorithms that bypass the sleep laboratory in favor of portable monitoring studies and in-home initiation of positive airway pressure therapy. For appropriately selected outpatients, evidence is accumulating that portable monitors are a reasonable substitute for in-laboratory polysomnography. In the inpatient setting, in which SDB is both highly prevalent and associated with adverse outcomes in certain populations, the literature is evolving on the use of portable monitors to expedite diagnosis and treatment of SDB. This review discusses society guidelines and recent research in the growing field of portable monitoring.

An Economic Evaluation of Home Versus Laboratory-Based Diagnosis of Obstructive Sleep Apnea

STUDY OBJECTIVES

We conducted an economic analysis of the HomePAP study, a multicenter randomized clinical trial that compared home-based versus laboratory-based testing for the diagnosis and management of obstructive sleep apnea (OSA).

DESIGN

A cost-minimization analysis from the payer and provider perspectives was performed, given that 3-mo clinical outcomes were equivalent.

SETTING

Seven academic sleep centers.

PARTICIPANTS

There were 373 subjects at high risk for moderate to severe OSA.

INTERVENTIONS

Subjects were randomized to either home-based limited channel portable monitoring followed by unattended autotitration with continuous positive airway pressure (CPAP), versus a traditional pathway of in-laboratory sleep study and CPAP titration.

MEASUREMENTS AND RESULTS

From the payer perspective, per subject costs for the laboratory-based pathway were $1,840 (95% confidence interval [CI] $1,660, $2,015) compared to $1,575 (95% CI $1,439, $1,716) for the home-based pathway under the base case. Costs were $264 (95% CI $39, $496, P = 0.02) in favor of the home arm. From the provider perspective, per subject costs for the laboratory arm were $1,697 (95% CI $1,566, $1,826) compared to $1,736 (95% CI $1,621, $1,857) in the home arm, for a difference of $40 (95% CI -$213, $142, P = 0.66) in favor of the laboratory arm under the base case. The provider operating margin was $142 (95% CI $85, $202,P < 0.01) in the laboratory arm, compared to a loss of -$161 (95% CI -$202, -$120, P < 0.01) in the home arm.

CONCLUSIONS

For payers, a home-based diagnostic pathway for obstructive sleep apnea with robust patient support incurs fewer costs than a laboratory-based pathway. For providers, costs are comparable if not higher, resulting in a negative operating margin.

CLINICALTRIALSGOV IDENTIFIER

NCT00642486.

Cost minimization using an artificial neural network sleep apnea prediction tool for sleep studies

RATIONALE

More than a million polysomnograms (PSGs) are performed annually in the United States to diagnose obstructive sleep apnea (OSA). Third-party payers now advocate a home sleep test (HST), rather than an in-laboratory PSG, as the diagnostic study for OSA regardless of clinical probability, but the economic benefit of this approach is not known.

OBJECTIVES

We determined the diagnostic performance of OSA prediction tools including the newly developed OSUNet, based on an artificial neural network, and performed a cost-minimization analysis when the prediction tools are used to identify patients who should undergo HST.

METHODS

The OSUNet was trained to predict the presence of OSA in a derivation group of patients who underwent an in-laboratory PSG (n = 383). Validation group 1 consisted of in-laboratory PSG patients (n = 149). The network was trained further in 33 patients who underwent HST and then was validated in a separate group of 100 HST patients (validation group 2). Likelihood ratios (LRs) were compared with two previously published prediction tools. The total costs from the use of the three prediction tools and the third-party approach within a clinical algorithm were compared.

MEASUREMENTS AND MAIN RESULTS

The OSUNet had a higher +LR in all groups compared with the STOP-BANG and the modified neck circumference (MNC) prediction tools. The +LRs for STOP-BANG, MNC, and OSUNet in validation group 1 were 1.1 (1.0-1.2), 1.3 (1.1-1.5), and 2.1 (1.4-3.1); and in validation group 2 they were 1.4 (1.1-1.7), 1.7 (1.3-2.2), and 3.4 (1.8-6.1), respectively. With an OSA prevalence less than 52%, the use of all three clinical prediction tools resulted in cost savings compared with the third-party approach.

CONCLUSIONS

The routine requirement of an HST to diagnose OSA regardless of clinical probability is more costly compared with the use of OSA clinical prediction tools that identify patients who should undergo this procedure when OSA is expected to be present in less than half of the population. With OSA prevalence less than 40%, the OSUNet offers the greatest savings, which are substantial when the number of sleep studies done annually is considered.

Validation of the Sonomat: a contactless monitoring system used for the diagnosis of sleep disordered breathing

STUDY OBJECTIVES

To evaluate the ability of the Sonomat to diagnose obstructive sleep apnea (OSA).

DESIGN

Prospective and randomized.

SETTING

Sleep laboratory and home.

PARTICIPANTS

62 subjects; 54 with a clinical history of OSA and 8 normal control subjects.

INTERVENTIONS

N/A.

MEASUREMENTS AND RESULTS

Simultaneous PSG and Sonomat recordings were made in 62 subjects; 2 were excluded due to a poor nasal flow recording in PSG. There were positive correlations between the two devices for measures of sleep time, respiratory events, and the AHI (all correlations > 0.89). Bland-Altman analysis of the AHI showed positive agreement between devices, particularly at levels around common diagnostic thresholds. The mean difference in AHI values was 1.4 events per hour, and at a diagnostic threshold of 15 events per hour, sensitivity and specificity were 88% and 91%. More than 93% of PSG defined respiratory events were identified by the Sonomat and the absence of respiratory events was correctly identified in 91% of occasions. Gender, obesity, and body position did not influence the accuracy of the Sonomat. PSG snore sensors differed in how much snoring was detected when compared to the Sonomat.

CONCLUSION

These data indicate that the Sonomat was reliable and accurate for the diagnosis of OSA. The provision of audible breath sound/snoring replay permits more accurate quantification of snoring. It requires no patient attachment and can be performed in the home with minimal training.

Home-based diagnosis of obstructive sleep apnea in an urban population

STUDY OBJECTIVES

Home-based diagnosis of obstructive sleep apnea (OSA) with portable monitoring (PM) is increasingly utilized, but remains understudied in underserved and minority populations. We tested the feasibility of home PM in an urban population at risk for OSA compared to in-laboratory polysomnography (PSG) and examined patient preference with respect to home PM versus PSG.

METHODS

Randomized crossover study of home PM (WatchPAT200) and in-laboratory simultaneous PSG and PM in 75 urban African Americans with high pre-test probability of OSA, identified with the Berlin questionnaire.

RESULTS

Fifty-seven of 75 participants were women, average age 45 ± 11 years (mean ± SD), 35% with ≤ high school education, and 76% with annual household income < $50,000. Technical failure rates were 5.3% for home vs. 3.1% for in-laboratory PM. There was good agreement between apnea hypopnea index on PSG; AHIPSG and AHI on home PM (mean ± 2 SD of the differences = 0.64 ± 46.5 and intraclass correlation coefficient; ICC = 0.73). The areas under the curve for the receiver-operator characteristic curves for home PM were 0.90 for AHIPSG ≥ 5, 0.95 for AHIPSG ≥ 10, and 0.92 for AHIPSG ≥ 15. 62/75 (82%) participants preferred home over in-laboratory testing.

CONCLUSIONS

Home PM for diagnosis of OSA in a high risk urban population is feasible, accurate, and preferred by patients. As home PM may improve access to care, the cost-effectiveness of this diagnostic strategy for OSA should be examined in underserved urban and rural populations.

CLINICAL TRIALS REGISTRATION

ClinicalTrials.gov, identifier: NCT01997723.

Obstructive sleep apnea patients having surgery are less associated with glaucoma

Objective. To investigate if different treatment strategy of obstructive sleep apnea (OSA) was associated glaucoma risk in Taiwanese population. Methods. Population-based retrospective cohort study was conducted using data sourced from the Longitudinal Health Insurance Database 2000. We included 2528 OSA patients and randomly selected and matched 10112 subjects without OSA as the control cohort. The risk of glaucoma in OSA patients was investigated based on the managements of OSA (without treatment, with surgery, with continuous positive airway pressure (CPAP) treatment, and with multiple modalities). The multivariable Cox regression was used to estimate hazard ratio (HR) after adjusting for sex, age, hypertension, diabetes, hyperlipidemia, and coronary artery disease. Results. The adjusted HR of glaucoma for OSA patients was 1.88 (95% CI: 1.46–2.42), compared with controls. For patients without treatment, the adjusted HR was 2.15 (95% CI: 1.60–2.88). For patients with treatments, the adjusted HRs of glaucoma were not significantly different from controls, except for those with CPAP (adjusted HR = 1.65, 95% CI = 1.09–2.49). Conclusions. OSA is associated with an increased risk of glaucoma. However, surgery reduces slightly the glaucoma hazard for OSA patients.

The Effect of the Transition to Home Monitoring for the Diagnosis of OSAS on Test Availability, Waiting Time, Patients' Satisfaction, and Outcome in a Large Health Provider System

During 2009, the Haifa district of Clalit Health Services (CHS) has switched from in-lab polysomnography (PSG) to home studies for the diagnosis of obstructive sleep apnea (OSA). We assessed the effects of this change on accessibility, waiting time, satisfaction, costs, and CPAP purchase by the patients. Data regarding sleep studies, CPAP purchase, and waiting times were collected retrospectively from the computerized database of CHS. Patients' satisfaction was assessed utilizing a telephone questionnaire introduced to a randomized small sample of 70 patients. Comparisons were made between 2007 and 2008 (in-lab PSGs) and 2010 and 2011 (when most studies were ambulatory). Of about 650000 insured individuals in the Haifa district of CHS, 1471 sleep studies were performed during 2007-2008 compared to 2794 tests during 2010-2011. The average waiting time was 9.9 weeks in 2007-2008 compared to 1.1 weeks in 2010-2011 (P < 0.05). 597 CPAPs were purchased in 2007-2008 compared to 831 in 2010-2011. The overall patients' satisfaction was similar, but discomfort tended to be higher in the in-laboratory group (4.1 vs 2.7 in a scale of 0-10; P = 0.11). Switching to ambulatory diagnosis improved the test accessibility and reduced the waiting times. Patients' satisfaction remained similarly high. The total direct cost of OSA management was reduced.

Vaccine adjuvant formulations: a pharmaceutical perspective

Formulation science is an unappreciated and often overlooked aspect in the field of vaccinology. In this review we highlight key attributes necessary to generate well characterized adjuvant formulations. The relationship between the adjuvant and the antigen impacts the immune responses generated by these complex biopharmaceutical formulations. We will use 5 well established vaccine adjuvant platforms; alum, emulsions, liposomes, PLG, and particulate systems such as ISCOMS in addition to immune stimulatory molecules such as MPL to illustrate that a vaccine formulation is more than a simple mixture of component A and component B. This review identifies the challenges and opportunities of these adjuvant platforms. As antigen and adjuvant formulations increase in complexity having a well characterized robust formulation will be critical to ensuring robust and reproducible results throughout preclinical and clinical studies.

Comparison of empirical continuous positive airway pressure (CPAP) treatment versus initial portable sleep monitoring followed by CPAP treatment for patients with suspected obstructive sleep apnoea

BACKGROUND

Polysomnography is labour-intensive for diagnosing obstructive sleep apnoea (OSA). We compared two algorithms for initiating continuous positive airway pressure (CPAP) treatment for patients with suspected OSA.

METHODS

Symptomatic OSA patients were randomised into either algorithm I or II. Algorithm I consisted of an empirical CPAP trial whereas algorithm II utilised an Apnea Risk Evaluation System, a wireless device applied on the forehead, for establishing a diagnosis before a CPAP trial for 3 weeks. Primary outcome was success of CPAP trial, defined as CPAP usage > 4 h/night and willingness to continue CPAP. Subjective usefulness of CPAP, accuracy of Apnea Risk Evaluation System versus polysomnography and CPAP adherence at 6 months were secondary end-points.

RESULTS

Altogether 138 patients in algorithm I and 110 patients in algorithm II completed the CPAP trial. There were no significant differences between these algorithms with respect to the primary end-point. The sensitivity and specificity of algorithm I versus II as a diagnostic test for OSA were 0.3, 0.8 versus 0.31, 1.00 respectively. In predicting CPAP adherence at 6 months, the likelihood ratio positive for algorithms I and II was 2.7 and 5.27 respectively. The mean (SE) time taken from the first consultation to the end of CPAP trial in algorithm I and algorithm II was 60 (2) and 98 (5) days, respectively, P < 0.01.

CONCLUSION

An ambulatory approach with portable sleep monitoring for diagnosing OSA before a CPAP trial can identify more patients who would adhere to CPAP at 6 months than empirical CPAP treatment alone.

Portable diagnostic devices for identifying obstructive sleep apnea among commercial motor vehicle drivers: considerations and unanswered questions

Obstructive sleep apnea (OSA), a syndrome defined by breathing abnormalities during sleep, can lead to fatigue and excessive daytime sleepiness (EDS) with an increased risk of motor vehicle crashes. Identifying commercial motor vehicle operators with unrecognized OSA is a major public health priority. Portable monitors (PMs) are being actively marketed to trucking firms as potentially lower-cost and more accessible alternatives to the reference standard of in-laboratory polysomnography (PSG) in the diagnosis of OSA among commercial motor vehicle operators. Several factors regarding PMs remain uncertain in this unique patient population: their sensitivity and specificity; the cost-benefit ratio of the PMs versus PSG; potential barriers from human factors; and evolving technologic advancement. Human factors that alter test accuracy are a major concern among commercial drivers motivated to gain/maintain employment. Current available data using PMs as a diagnostic tool among CMV operators indicate relatively high data loss and high loss to follow-up. Loss to follow-up has also been an issue using PSG in commercial motor vehicle operators. Furthermore, PM testing and PM results interpretation protocols may have no sleep specialist oversight, and sometimes minimal physician oversight and involvement. Additional studies comparing unattended and unmonitored PMs directly against full in-laboratory PSG are needed to provide evidence for their efficacy among commercial motor vehicle operators.

Comparison of polysomnographic and portable home monitoring assessments of obstructive sleep apnea in Saskatchewan women

OBJECTIVES

To compare a commercially available, level III in-home diagnostic sleep test (Embletta, Embletta USA) and in-laboratory polysomnography (PSG) in women with suspected obstructive sleep apnea (OSA).

METHODS

Consecutive women scheduled for routine PSG testing for evaluation of clinically suspected OSA and who met inclusion⁄exclusion criteria, were invited to participate. An in-home Embletta portable monitor test was performed one week before or after diagnostic PSG.

RESULTS

Forty-seven of 96 women who met the inclusion⁄exclusion criteria agreed to participate. The mean (± SD) age of the patients was 52.0 ± 11.0 years, with a mean body mass index of 34.86 ± 9.04 kg⁄m2, and 66% (31 of 47) of patients were at high risk for OSA according to the Berlin score. Paired analysis of the overall population revealed no significant difference in mean apnea⁄hypopnea index (AHI) between the two diagnostic methods (P = 0.475). At an AHI of ≥ 5, the Embletta test was highly sensitive (90.6%) in determining abnormal versus normal OSA, with a positive predictive value of 82.7%. However, a higher Embletta AHI threshold of ≥ 10 may be more useful, with a higher level of agreement (kappa coefficient) with PSG testing and a positive predictive value of 92.3%. The in-home study was less useful at distinguishing severe from nonsevere OSA, yielding a sensitivity of 50%.

CONCLUSIONS

In women believed to be at high-risk for OSA, Embletta in-home sleep testing is useful for the detection of sleep disordered breathing.

An integrated health-economic analysis of diagnostic and therapeutic strategies in the treatment of moderate-to-severe obstructive sleep apnea

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is a common disorder associated with substantially increased cardiovascular risks, reduced quality of life, and increased risk of motor vehicle collisions due to daytime sleepiness. This study evaluates the cost-effectiveness of three commonly used diagnostic strategies (full-night polysomnography, split-night polysomnography, unattended portable home-monitoring) in conjunction with continuous positive airway pressure (CPAP) therapy in patients with moderate-to-severe OSA.

DESIGN

A Markov model was created to compare costs and effectiveness of different diagnostic and therapeutic strategies over a 10-year interval and the expected lifetime of the patient. The primary measure of cost-effectiveness was incremental cost per quality-adjusted life year (QALY) gained.

PATIENTS OR PARTICIPANTS

Baseline computations were performed for a hypothetical average cohort of 50-year-old males with a 50% pretest probability of having moderate-to-severe OSA (apnea-hypopnea index [AHI] ≥ 15 events per hour).

MEASUREMENTS AND RESULTS

For a patient with moderate-to-severe OSA, CPAP therapy has an incremental cost-effectiveness ratio (ICER) of $15,915 per QALY gained for the lifetime horizon. Over the lifetime horizon in a population with 50% prevalence of OSA, full-night polysomnography in conjunction with CPAP therapy is the most economically efficient strategy at any willingness-to-pay greater than $17,131 per-QALY gained because it dominates all other strategies in comparative analysis.

CONCLUSIONS

Full-night polysomnography (PSG) is cost-effective and is the preferred diagnostic strategy for adults suspected to have moderate-to-severe OSA when all diagnostic options are available. Split-night PSG and unattended home monitoring can be considered cost-effective alternatives when full-night PSG is not available.

Validation of the MediByte® type 3 portable monitor compared with polysomnography for screening of obstructive sleep apnea

BACKGROUND

Portable monitors are increasingly being used as a diagnostic screening tool for obstructive sleep apnea (OSA), and in-laboratory validation of these devices with polysomnography (PSG) is required.

OBJECTIVE

To assess the reliability of the MediByte (Braebon Medical Corporation, Canada) type 3 screening device compared with overnight PSG.

METHODS

To cover a range of OSA severity, a consecutive series of patients wore the screening device while simultaneously undergoing PSG. Data acquired from the screener and PSG were blinded and scored separately. The number of apneas and hypopneas per hour were calculated using recording time (respiratory disturbance index [RDI]) for the MediByte device, and sleep time (apnea-hypopnea index [AHI]) for PSG.

RESULTS

Data from 73 patients with a mean age of 53 years and body mass index of 32.2 kg⁄m2 showed high measurement association between the RDI and AHI, with a Pearson correlation of 0.92, accounting for 85% of the variance. Based on Bland-Altman measurement agreement, the mean difference between the RDI and AHI (-5.9±11.2 events⁄h) indicated screener under-reporting. For an AHI of greater than 15 events⁄h, the sensitivity and specificity of the screener was 80% and 97%, respectively; for an AHI of greater than 30 events⁄h, the positive predictive value was 100%, while the negative predictive value was 88%.

CONCLUSION

The MediByte device accurately identified patients without OSA and had a high sensitivity for moderate-to-severe OSA.

High risk for sleep apnea in the Berlin questionnaire and coronary artery disease

INTRODUCTION

Obstructive sleep apnea (OSA) affects up to 30% of the adult population and is a risk factor for coronary artery disease (CAD). The diagnostic process, involving polysomnography, may be complex. Berlin questionnaire (BQ) is a validated and economical screening tool.

PURPOSE

The aim of this study was to assess the performance of the BQ for the diagnosis of OSA in individuals with angina complaints.

METHODS

Patients undergoing diagnostic cineangiography, portable type III polysomnography to determine the apnea-hypopnea index (AHI), and who answered the BQ were included. We excluded patients older than 65 years that were smokers, diabetics, and morbidly obese. High risk for OSA was based on positive responses in two of three symptom criteria of the BQ. CAD was defined by the presence of >50% lesion in coronary arteries.

RESULTS

In 57 included cases, high risk in the BQ indicates significant odds ratio [95% confidence interval] for the presence of CAD (4.5[1.03-19.25], P = 0.045), adjusted for usual confounders: gender, age, and body mass index. The sensitivity and the specificity of BQ for CAD were 70% and 48%, respectively; the positive and negative predictive values are 56% and 64%.

CONCLUSIONS

In conclusion, simple questionnaire-based diagnostic tools can be included in the screening procedures of patients with angina to detect the need for further OSA evaluation. In conclusion, the BQ is an effective instrument for this purpose.