Characterization of primary symptoms leading to Chinese patients presenting at hospital with suspected obstructive sleep apnea

Objectives

We identified the primary symptoms leading to Chinese patients presenting at hospital with suspected obstructive sleep apnea (OSA) and studied the prevalence and characteristics of OSA in confirmed cases.

Methods

We collected data on 350 consecutive patients (302 males and 43±11 years old) with suspected OSA who underwent overnight polysomnography (PSG).

Results

Among all patients, rankings of primary symptoms that led to the patients presenting at hospital for PSG were observed apnea (33%), snoring alone (29%), choking/gasping (13%), daytime sleepiness (5%) and other (20%). For severe OSA, prevalence rate was 61%, apnea hypopnea index (AHI) was 64±18, age was 44±10 years old, body mass index (BMI) was 28±3.5 kg/m², and hypertension rate was 28%.

Conclusions

Self-awareness of symptoms led a majority of the patients to present at hospital in China. Compared to currently available case series studies, our results suggest that OSA patients in East Asian countries are characterized by higher prevalence and more severe apnea, younger age, poorer sleep quality, but less obesity and less comorbidity with hypertension, relative to countries in North America, South America and Europe.     

Obstructive sleep apnea related to rapid-eye-movement or non-rapid-eye-movement sleep: comparison of demographic,anthropometric, and polysomnographic features

Objective

: To determine whether there are significant differences between rapid-eye-movement (REM)-related obstructive sleep apnea (OSA) and non-REM (NREM)-related OSA, in terms of the demographic, anthropometric, and polysomnographic characteristics of the subjects.

Methods

: This was a retrospective study of 110 patients (75 males) with either REM-related OSA (n = 58) or NREM-related OSA (n = 52). To define REM-related and NREM-related OSA, we used a previously established criterion, based on the apnea-hypopnea index (AHI): AHI-REM/AHI-NREM ratio > 2 and ≤ 2, respectively.

Results

: The mean age of the patients with REM-related OSA was 49.5 ± 11.9 years, whereas that of the patients with NREM-related OSA was 49.2 ± 12.6 years. The overall mean AHI (all sleep stages combined) was significantly higher in the NREM-related OSA group than in the REM-related OSA group (38.6 ± 28.2 vs. 14.8 ± 9.2; p < 0.05). The mean AHI in the supine position (s-AHI) was also significantly higher in the NREM-related OSA group than in the REM-related OSA group (49.0 ± 34.3 vs. 18.8 ± 14.9; p < 0.0001). In the NREM-related OSA group, the s-AHI was higher among the men. In both groups, oxygen desaturation was more severe among the women. We found that REM-related OSA was more common among the patients with mild-to-moderate OSA, whereas NREM-related OSA was more common among those with severe OSA.

Conclusions

: We found that the severity of NREM-related OSA was associated mainly with s-AHI. Our findings suggest that the s-AHI has a more significant effect on the severity of OSA than does the AHI-REM. When interpreting OSA severity and choosing among treatment modalities, physicians should take into consideration the sleep stage and the sleep posture.     

Excessive daytime sleepiness among rural residents in Saskatchewan

BACKGROUND:

Obstructive sleep apnea (OSA) is a common diagnosis in clinical practice. Excessive daytime sleepiness may be a warning for possible OSA.

OBJECTIVES:

To assess the prevalence of excessive daytime sleepiness as measured by the Epworth Sleepiness Scale (ESS) in a rural community population; potential risk factors for OSA were also assessed.

METHODS:

In 2010, a baseline respiratory health questionnaire within the Saskatchewan Rural Health Study was mailed to 11,982 households in Saskatchewan. A total of 7597 adults within the 4624 (42%) respondent households completed the ESS questionnaire. Participants were categorized according to normal or high (>10) ESS scores. Data obtained included respiratory symptoms, doctor-diagnosed sleep apnea, snoring, hypertension, smoking and demographics. Body mass index was calculated. Multivariable logistic regression analysis examined associations between high ESS scores and possible risk factors. Generalized estimating equations accounted for the two-tiered sampling procedure of the study design.

RESULTS:

The mean age of respondents was 55.0 years and 49.2% were male. The prevalence of ESS>10 and ‘doctor diagnosed’ OSA were 15.9% and 6.0%, respectively. Approximately 23% of respondents reported loud snoring and 30% had a body mass index >30 kg/m². Of those with ‘doctor-diagnosed’ OSA, 37.7% reported ESS>10 (P<0.0001) and 47.7% reported loud snoring (P<0.0001). Risk of having an ESS>10 score increased with age, male sex, obesity, lower socioeconomic status, marriage, loud snoring and doctor-diagnosed sinus trouble.

CONCLUSIONS:

High levels of excessive daytime sleepiness in this particular rural population are common and men >55 years of age are at highest risk. Examination of reasons for residual sleepiness and snoring in persons with and without sleep apnea is warranted.     

Do obstructive sleep apnea syndrome patients underestimate their daytime symptoms before continuous positive airway pressure treatment?

BACKGROUND:

Daytime somnolence is an important feature of the obstructive sleep apnea (OSA) hypopnea syndrome and is usually subjectively assessed using the Epworth Sleepiness Scale (ESS).

OBJECTIVE:

To compare the scores of the ESS and different domains of the Quebec Sleep Questionnaire (QSQ) assessed before and after the first months of continuous positive airway pressure (CPAP) treatment, as well as retrospectively without treatment.

METHODS:

The ESS score and domain scores of the QSQ were obtained before and after a three-month period of CPAP treatment using a retrospective assessment of the pretreatment scores in 76 untreated OSA patients.

RESULTS:

Fifty-two patients completed the study. The ESS and QSQ scores significantly improved following CPAP therapy. Retrospective evaluation of the ESS score was significantly worse than pre- and post-treatment values (mean [± SD] pretreatment score 11.0±4.8; retrospective pretreatment score 13.5±5.1). Such differences were not observed in any domain of the QSQ, including the domain assessing hypersomnolence.

CONCLUSION:

OSA patients underestimated their sleepiness according to the most widely used instrument to assess hypersomnolence. This finding may not be observed with other methods used to assess OSA-related symptoms such as quality of life questionnaires.     

Overnight fluid shifts in subjects with and without obstructive sleep apnea

Objective

To investigate the characteristics of baseline body fluid content and overnight fluid shifts between non-obstructive sleep apnea (non-OSA) and obstructive sleep apnea (OSA) subjects.

Methods

A case-controlled study was performed between February 2013 and January 2014, with 36 (18 OSA and 18 non-OSA) outpatients enrolled in this study. Polysomnographic parameters and results of body fluid were compared between the two groups.

Results

There were no differences in age, weight, and body mass index (BMI) between groups. Compared with the non-OSA group, OSA group had significantly higher neck circumference (NC) and fluid volume shift in the legs. OSA patients had higher left and right leg fluid indices than non-OSA subjects. There were significant correlations between apnoea-hypopnoea index and baseline fluid indices in both legs as well as the reduction in overnight change in both legs fluid volume. The increase in NC was also significantly correlated with the reduction in overnight change in both legs fluid volume, but not with the change in head and neck fluid volume. There were significant correlations between change in NC and increased fluid shifts in head and neck volume.

Conclusions

OSA patients had a higher baseline fluid content in both legs as compared with non-OSA subjects, which may be the basic factor with regards to fluid shifts in OSA patients. The increase in head and neck fluid shift volume did not directly correlate with the severity of OSA.     

Association Between the Severity of Nocturnal Hypoxia in Obstructive Sleep Apnea and Non-Alcoholic Fatty Liver Damage

Background:

Obstructive sleep apnea (OSA) is a major disease that can cause significant mortality and morbidity. Chronic intermittent hypoxia is a potential causal factor in the progression from fatty liver to nonalcoholic steatohepatitis.

Objectives:

This study evaluated the association between the degree of liver steatosis and severity of nocturnal hypoxia.

Patients and Methods:

In this study, between December 2011 and December 2013, patients with ultrasound-diagnosed NAFLD evaluated by standart polysomnography were subsequentally recorded. Patients with alcohol use, viral hepatitis and other chronic liver diseases were excluded. We analyzed polysomnographic parameters, steatosis level and severity of obstructive sleep apnea (OSA) in consideration of body mass index (BMI), biochemical tests and ultrasonographic liver data of 137 subjects. Patients with sleep apnea and AHI scores of < 5, 5 - 14, 15 - 29 and ≥30 are categorized as control, mild, moderate and severe, respectively.

Results:

One hundred and thirty-seven patients (76 women, 61 men) with a mean age of 55.75 ± 10.13 years who underwent polysomnography were included in the study. Of 118 patients diagnosed with OSA, 19 (16.1%) had mild OSA, 39 (33.1%) moderate OSA and 60 (50.8%) severe OSA. Nineteen cases formed the control group. Apnea/hypopnea index and oxygen desaturation index (ODI) values were significantly higher in moderate and severe non-alcoholic fatty liver disease (NAFLD) compared to the non-NAFLD group. Mean nocturnal SpO₂ values were significantly lower in mild NAFLD and severe NAFLD compared to the non-NAFLD group. Lowest O₂ saturation (LaSO₂) was found low in mild, moderate and severe NAFLD compared to the non-NAFLD group in a statistically significant manner.

Conclusions:

We assessed polysomnographic parameters of AHI, ODI, LaSO₂ and mean nocturnal SpO₂ levels, which are especially important in the association between NAFLD and OSAS. We think that it is necessary to be attentive regarding NAFLD development and progression in patients with OSA whose nocturnal hypoxia is severe.     

Screening for sleep-disordered breathing in a bariatric population

Background

Obstructive sleep apnea (OSA) is the most common form of sleep-disordered breathing frequently associated with obesity. Obese subjects undergoing elective surgical procedures with general anesthesia are potentially at risk if this condition is not identified. Our aim was to assess the prevalence of bariatric patients with undiagnosed OSA following pre-operative assessment and who could benefit from peri-procedural respiratory management.

Methods

Patients who were referred for prospective bariatric surgery were screened using the STOP-BANG questionnaire. If patients scored >4 points they underwent a home-based nocturnal pulse oximetry. Severity of OSA was defined by the 4% oxygen desaturation index (ODI) combined with a physician’s review. Data were compared using unpaired two-tailed t-test and Chi-square test. Linear regression models were used to assess associations between clinical parameters.

Results

Sleep-disordered breathing of any degree was evident in 103 of 141 patients (73%). Thirteen (9%) patients had severe, 19 (13%) moderate, and 34 (24%) mild OSA, 38 (27%) patients had no OSA. 34 (24%) patients were initiated on continuous positive airway pressure (CPAP) prior to the surgical procedure, 15 (11%) were admitted for further respiratory assessment and two of them were given CPAP following inpatient sleep study. Thirteen (9%) patients were advised to use a mandibular advancement device for mild but symptomatic OSA. Out of all patients, 76 (54%) were advised that no treatment was required.

Conclusions

OSA is highly prevalent in a cohort of bariatric surgery patients screened with STOP-BANG questionnaires. Almost 3/4 of this cohort have at least some degree of sleep-disordered breathing, and approximately half of them require a plan for the respiratory management perioperatively.     

Sleep laboratory test referrals in Canada: Sleep Apnea Rapid Response Survey

BACKGROUND:

An estimated 5.4 million Canadian adults have been diagnosed with sleep apnea or are at high risk of experiencing obstructive sleep apnea (OSA). There are no recent Canadian data regarding access to and predictors of referral for diagnostic testing in these populations.

METHODS:

The Sleep Apnea Rapid Response survey sampled 8647 Canadian adults and captured information about risk, testing, diagnosis and treatment of sleep apnea. Predictors of sleep laboratory test referrals were assessed using log-linked binomial regression modelling. Information regarding sleep testing facilities was updated at the provincial and regional levels.

RESULTS:

Approximately 76.8% (95% CI 70.1% to 83.6%) of adult Canadians with sleep apnea and 5.1% (95% CI 3.4% to 6.7%) of those at high risk for OSA reported being referred to a sleep laboratory. Significant predictors of sleep laboratory referral in the general population were male sex, middle age, overweight or obese, a chronic condition, having a regular medical doctor and reporting symptoms of sleep apnea. Region of residence was also a predictor of reported sleep laboratory referral, with individuals from Ontario being more likely to report being referred to a sleep laboratory versus individuals from other regions.

CONCLUSION:

Individuals reporting risk factors and symptoms associated with OSA were more likely to report a sleep laboratory testing referral compared with those without risk factors or symptoms. However, Canada’s diagnostic sleep laboratory testing capacity varies across regions and is believed to be inadequate given the number of individuals at high risk for OSA who did not report testing referral.     

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 Prevalence of Obstructive Sleep Apnea and Its Association with Renal Function among Nondialysis Chronic Kidney Disease Patients in Japan: A Cross-Sectional Study

Summary

Background and objectives

Obstructive sleep apnea (OSA) affects one of five adults in the general population. Although a high prevalence of OSA has been reported among dialysis patients, the association between nondialysis chronic kidney disease (CKD) and OSA has not been fully investigated. This cross-sectional study aimed to investigate the prevalence of OSA among nondialysis CKD patients in Japan and the association between renal function and OSA.

Design, setting, participants, & measurements

Consecutive nondialysis CKD patients hospitalized mainly for CKD educational program, regardless of their sleep complaints, were enrolled. The diagnosis of OSA and its severity were measured using a type 3 portable monitor.

Results

Overall (n = 100, 68.0% male, median age 66.5 years, body mass index [BMI] 23.1 kg/m², estimated GFR [eGFR] 28.5 ml/min per 1.73 m²), 65% were diagnosed as OSA: mild OSA (apnea-hypopnea index [AHI] 5.0 to 14.9) in 32%, moderate OSA (AHI 15.0 to 29.9) in 25%, and severe OSA (AHI ≥ 30.0) in 8%. Multivariate logistic regression analysis revealed that a 10-ml/min per 1.73 m² decrease in eGFR was associated with a 42% increased odds of OSA after adjustment for age, BMI, and diabetes mellitus. Moreover, in a generalized linear model, eGFR was inversely correlated with AHI after adjustment for covariates.

Conclusions

This study demonstrated a high prevalence of OSA among nondialysis CKD patients in Japan and that the increased risk of OSA was significantly associated with decreased GFR among these patients. Further investigations are warranted to determine OSA''s direct influence on cardiovascular disease.     

The utility of a portable sleep monitor to diagnose sleep-disordered breathing in a pediatric population

BACKGROUND:

Central and/or obstructive sleep-disordered breathing (SDB) in children represents a spectrum of abnormal breathing during sleep. SDB is diagnosed using the gold standard, overnight polysomnography (PSG). The limited availability and access to PSG prevents its widespread use, resulting in significant delays in diagnosis and treatment of SDB. As such, portable sleep monitors are urgently needed.

OBJECTIVE:

To evaluate the utility of a commercially available portable sleep study monitor (PSS-AL) (ApneaLink, ResMed, USA) to diagnose SDB in children.

METHODS:

Children referred to a pediatric sleep facility were simultaneously monitored using the PSS-AL monitor and overnight PSG. The apnea-hypopnea index (AHI) was calculated using the manual and autoscoring function of the PSS-AL, and PSG. Sensitivity and specificity were compared with the manually scored PSS-AL and PSG. Pearson correlations and Bland-Altman plots were constructed.

RESULTS:

Thirty-five children (13 female) completed the study. The median age was 11.0 years and the median body mass index z-score was 0.67 (range −2.3 to 3.8). SDB was diagnosed in 17 of 35 (49%) subjects using PSG. The AHI obtained by manually scored PSS-AL strongly correlated with the AHI obtained using PSG (r=0.89; P<0.001). Using the manually scored PSS-AL, a cut-off of AHI of >5 events/h had a sensitivity of 94% and a specificity of 61% to detect any SDB diagnosed by PSG.

CONCLUSIONS:

Although PSG is still recommended for the diagnosis of SDB, the ApneaLink sleep monitor has a role for triaging children referred for evaluation of SDB, but has limited ability to determine the nature of the SDB.     

Prevalence of high Epworth Sleepiness Scale scores in a rural population

BACKGROUND:

Increased daytime sleepiness is an important symptom of obstructive sleep apnea (OSA). OSA is frequently underdiagnosed, and the Epworth Sleepiness Scale (ESS) can be a useful tool in alerting physicians to a potential problem involving OSA.

OBJECTIVE:

To measure the prevalence and determinants of daytime sleepiness measured using the ESS in a rural community population.

METHODS:

A community survey was conducted to examine the risk factors associated with ESS in a rural population in 154 households comprising 283 adults. Questionnaire information was obtained regarding physical factors, social factors, general medical history, family medical history, ESS score, and self-reported height and weight. Multivariable binary logistic regression analysis based on the generalized estimating equations approach to account for clustering within households was used to predict the relationship between a binary ESS score outcome (normal or abnormal) and a set of explanatory variables.

RESULTS:

The population included 140 men (49.5%) and 143 women (50.5%) with an age range of 18 to 97 years (mean [± SD] 52.0±14.9 years). The data showed that 79.2% of the study participants had an ESS score in the normal range (0 to 10) and 20.8% had an ESS score >10, which is considered to be abnormal or high sleepiness. Multivariable regression analysis revealed that obesity was significantly associated with an abnormal or high sleepiness score on the ESS (OR 3.40 [95% CI 1.31 to 8.80).

CONCLUSION:

High levels of sleepiness in this population were common. Obesity was an important risk factor for high ESS score.     

Coagulability in obstructive sleep apnea

BACKGROUND:

Obstructive sleep apnea (OSA) is a common disorder that affects both quality of life and cardiovascular health. The causal link between OSA and cardiovascular morbidity/mortality remains elusive. One possible explanation is that repeated episodes of nocturnal hypoxia lead to a hypercoagulable state that predisposes patients to thrombotic events. There is evidence supporting a wide array of hematological changes that affect hemostasis (eg, increased hematocrit, blood viscosity, platelet activation, clotting factors and decreased fibrinolytic activity).

OBJECTIVE:

To provide a comprehensive review of the current evidence associating OSA with increased coagulability, and to highlight areas for future research.

METHODS:

Keyword searches in Ovid Medline were used to identify relevant articles; all references in the articles were searched for relevant titles. The Web of Science was used to identify articles citing the relevant articles found using the Ovid Medline search. All original peer-reviewed articles, meta-analyses and systematic reviews regarding the pertinent topics between 1990 and present were selected for review.

RESULTS:

Hematocrit, blood viscosity, certain clotting factors, tissue factor, platelet activity and whole blood coagulability are increased in patients with OSA, while fibrinolysis is impaired.

CONCLUSION:

There is considerable evidence that OSA is associated with a procoagulant state. Several factors are involved in the procoagulant state associated with OSA. There is a need for adequately powered clinical studies involving well-matched control groups to address potential confounding variables, and to accurately delineate the individual factors involved in the procoagulant state associated with OSA and their response to treatment.     

Wait times for sleep apnea care in Ontario: A multidisciplinary assessment

BACKGROUND:

Obstructive sleep apnea (OSA) is a highly prevalent disorder that is associated with significant patient morbidity and societal burden. In general, wait times for health care in Ontario are believed to be lengthy; however, many diseases lack specific corroborative wait time data.

OBJECTIVE:

To characterize wait times for OSA care in Ontario.

METHODS:

Cross-sectional survey. A survey tool was designed and validated to question physicians involved in OSA care about the length of the wait times their patients experience while traversing a simplified model of OSA care. The survey was sent to all otolaryngologists and respirologists in the province, as well as to a random sample of provincial family physicians.

RESULTS:

Patients waited a mean of 11.6 months to initiate medical therapy (continuous positive airway pressure), and 16.2 months to initiate surgical therapy. Sleep laboratory availability appeared to be the major restriction in the patient management continuum, with each additional sleep laboratory in a community associated with a 20% decrease in overall wait times. Smaller community sizes were paradoxically associated with shorter wait times for sleep studies (P<0.01) but longer wait times for OSA surgery (P<0.05). Regression analysis yielded an r² of 0.046; less than 5% of the wait time variance could be explained by the simplified model.

CONCLUSION:

Patients experienced considerable wait times when undergoing management for OSA. This has implications for both individual patient care and public health in general.     

Analysis of hospital discharge data to characterize obstructive sleep apnea and its management in adult patients hospitalized in Canada: 2006 to 2007

BACKGROUND:

Diagnosed obstructive sleep apnea (OSA) affects 2% to 7% of middle-age persons worldwide and represents a substantial health care burden. The gold standard for treating OSA in adults is continuous positive airway pressure (CPAP) therapy. Compliance with this treatment is especially important in OSA patients experiencing concomitant acute and chronic disease or illness, and those undergoing procedures associated with sedation, analgesia and anesthesia.

OBJECTIVE:

To describe the clinical characteristics and management of hospitalized OSA patients in Canada.

METHODS:

Using the Canadian Institute for Health Information’s hospital Discharge Abstract Database (fiscal year 2006/2007), a retrospective cohort study of all acute care patients discharged with a diagnosis that included OSA was performed.

RESULTS:

An examination of the discharge data of 2,400,245 acute care hospital abstracts identified 8823 cases of OSA. The mean age of OSA patients was 45.7 years and 66.5% were men. The most common comorbidities in the adult OSA population were obesity, cardiovascular disease, type 2 diabetes mellitus and chronic obstructive pulmonary disease. In adult OSA patients, the reported surgical intervention rate using uvulopalatopharyngoplasty (9.6%) was much higher than interventional CPAP therapy (4.8%).

CONCLUSIONS:

Only a small percentage of hospitalized OSA patients were documented as having received CPAP therapy during their stay. Issues relating to the accuracy, specificity and completeness of the Canadian Institute for Health Information’s hospital Discharge Abstract Database specific to OSA and its management were identified. Practices pertaining to the reporting, coding and management of hospitalized adult OSA patients warrant further investigation and research.     

Subjective sleepiness and daytime functioning in bariatric patients with obstructive sleep apnea

Purpose

The purpose of this study was to evaluate associations between obstructive sleep apnea (OSA) severity and self-reported sleepiness and daytime functioning in patients considering bariatric surgery for treatment of obesity.

Methods

Using a retrospective cohort design, we identified 342 patients who had sleep evaluations prior to bariatric surgery. Our final sample included 269 patients (78.6 % of the original cohort, 239 females; mean age?=?42.0?±?9.5 years; body mass index?=?50.2?±?7.7 kg/m²) who had overnight polysomnography and completed the Epworth Sleepiness Scale (ESS) and the Functional Outcomes of Sleep Questionnaire (FOSQ). Patients' OSA was classified as none/mild (apnea–hypopnea index (AHI)?<?15, n?=?112), moderate (15?≤?AHI?<?30, n?=?77), or severe (AHI?≥?30, n?=?80). We calculated the proportion of unique variance (PUV) for the five FOSQ subscales. ANOVA was used to determine if ESS and FOSQ were associated with OSA severity. Unpaired t tests compared ESS and FOSQ scores in our sample with published data.

Results

The average AHI was 29.5?±?31.5 events per hour (range?=?0–175.8). The mean ESS score was 6.3?±?4.8, and the mean global FOSQ score was 100.3?±?18.2. PUVs for FOSQ subscales showed moderate-to-high unique contributions to FOSQ variance. ESS and global FOSQ score did not differ by AHI group. Only the FOSQ vigilance subscale differed by OSA severity with the severe group reporting more impairment than the moderate and none/mild groups. Our sample reported less sleepiness and daytime impairment than previously reported means in patients and controls.

Conclusions

Subjective sleepiness and functional impairment were not associated significantly with OSA severity in our sample of patients considering surgery for obesity. Further research is needed to understand individual differences in sleepiness in patients with OSA. If bariatric patients underreport symptoms, self-report measures are not an adequate substitute for objective assessment and clinical judgment when evaluating bariatric patients for OSA. Patients with severe obesity need evaluation for OSA even in the absence of subjective complaints.     

Diagnostic accuracy of level IV portable sleep monitors versus polysomnography for obstructive sleep apnea: a systematic review and meta-analysis

Purpose

Obstructive sleep apnea (OSA) is the most common sleep-related breathing disorder. In-laboratory, overnight type I polysomnography (PSG) is the current “gold standard” for diagnosing OSA. Home sleep apnea testing (HSAT) using portable monitors (PMs) is an alternative testing method offering better comfort and lower costs. We aimed to systematically review the evidence on diagnostic ability of type IV PMs compared to PSG in diagnosing OSA.

Methods

Participants: patients ≥16 years old with symptoms suggestive of OSA;intervention: type IV PMs (devices with <?2 respiratory channels); comparator: in-laboratory PSG; outcomes: diagnostic accuracy measures;studies: cross-sectional, prospective observational/experimental/quasi-experimental studies; information sources: MEDLINE and Cochrane Library from January 1, 2010 to May 10, 2016. All stages of review were conducted independently by two investigators.

Results

We screened 6054 abstracts and 117 full-text articles to select 24 full-text articles for final review. These 24 studies enrolled a total of 2068 patients with suspected OSA and evaluated 10 different PMs with one to six channels. Only seven (29%) studies tested PMs in the home setting. The mean difference (bias) between PSG-measured and PM-measured apnea-hypopnea index (AHI) ranged from ??14.8 to 10.6 events/h. At AHI ≥?5 events/h, the sensitivity of type IV PMs ranged from 67.5–100% and specificity ranged from 25 to 100%.

Conclusion

While current evidence is not very strong for the stand-alone use of level IV PMs in clinical practice, they can potentially widen access to diagnosis and treatment of OSA. Policy recommendations regarding HSAT use should also consider the health and broader social implications of false positive and false negative diagnoses.