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1.  Validation of the STOP-BANG Questionnaire among Patients Referred for Suspected Obstructive Sleep Apnea 
Journal of sleep disorders-- treatment & care  2013;2(4):10.4172/2325-9639.1000121.
The STOP-BANG is a simple obstructive sleep apnea (OSA) screening tool, part questionnaire (STOP) and part demographic or physical measures (BANG), developed for use in preoperative surgical clinics. This study assessed sensitivity and specificity of the instrument among patients referred to a sleep disorders laboratory, and also its performance characteristics when BANG physical measures are patient-reported rather than measured.
Adults referred for diagnostic polysomnography completed the STOP questions and answered four yes/no questions (BANG self-reported) about their body mass index (weight and height), age, neck circumference, and gender, which were also assessed by laboratory technologists (BANG-measured).
Among N=219 subjects (mean age 46.3 ± 13.9 [s.d.] years; 98 [44.8%] males) the sensitivity of the STOP-BANG measured for an apnea/hypopnea index (AHI, events per hour of sleep) >5, >15, and >30 was 82, 93, and 97% respectively. Corresponding negative predictive values were 44, 87, and 96%. Specificities were comparatively low (48, 40, and 33%). The STOP-BANG measured and STOP-BANG self-reported scores showed essentially equivalent test characteristics against polysomnography.
The STOP-BANG appears to have limited utility in a referred, sleep laboratory setting. Negative results help to identify some individuals as unlikely to have moderate-to-severe apnea, and may thereby prove useful in identification of patients who would benefit more from laboratory studies than home studies. A STOP-BANG in which all information is self-reported may be as effective as the original version, and has potential to facilitate research or community screening where good negative predictive value is required for an effective screening tool.
PMCID: PMC4008971  PMID: 24800262
Sleep apnea; Obstructive; STOP-BANG; Questionnaire; Polysomnography; Screening tests; Sleepiness; Sleep disordered breathing
2.  High STOP-BANG questionnaire scores predict intraoperative and early postoperative adverse events 
Singapore Medical Journal  2015;56(4):212-216.
Obstructive sleep apnoea (OSA) is the most common sleep-related breathing disorder associated with multisystemic organ involvement. The STOP-BANG questionnaire is a concise, validated questionnaire that is used to screen for OSA. This study aimed to establish the use of the STOP-BANG questionnaire for perioperative patient risk stratification.
In this retrospective cohort study, we extracted the demographic, medical and perioperative outcome data of all patients who underwent elective surgery, excluding ophthalmic surgeries, from January to December 2011. Multivariate regression analysis was used to predict independent risk factors for intraoperative and early postoperative adverse events.
Of the 5,432 patients analysed, 7.4% had unexpected intraoperative and early postoperative adverse events. We found that the risk of unexpected intraoperative and early postoperative adverse events was greater in patients with STOP-BANG scores ≥ 3 compared to those with a STOP-BANG score of 0 (score 3: odds ratio [OR] 3.6, 95% confidence interval [CI] 2.1–6.3, p < 0.001; score 4: OR 3.4, 95% CI 1.8–6.5, p < 0.001; score 5: OR 6.4, 95% CI 2.7–15.0, p < 0.001; score ≥ 6: OR 5.6, 95% CI 2.1–15.4, p < 0.001). Patients with STOP-BANG scores ≥ 5 had a fivefold increased risk of unexpected intraoperative and early postoperative adverse events, while patients with STOP-BANG scores ≥ 3 had a ‘one in four’ chance of having an adverse event. Other independent predictors included older age (p < 0.001), American Society of Anesthesiologists class ≥ 2 (p < 0.003) and uncontrolled hypertension (p = 0.028).
STOP-BANG score may be used as a preoperative risk stratification tool to predict the risk of intraoperative and early postoperative adverse events.
PMCID: PMC4415101  PMID: 25917473
adverse events; obstructive sleep apnoea; perioperative complications; STOP-BANG questionnaire
3.  Predicting sleep disordered breathing in outpatients with suspected OSA 
BMJ Open  2014;4(4):e004519.
To validate the utilities of Berlin, STOP and STOP-BANG Questionnaires, other patient characteristics, comorbidities, Epworth Sleepiness Scale (ESS), fractional exhaled nitric oxide (FENO) and blood markers for the prediction of sleep disordered breathing (SDB) on limited polygraphy.
North Glasgow Sleep Service (a tertiary referral centre).
129 consecutive patients, aged ≥16 years, referred to the sleep clinic for assessment of possible obstructive sleep apnoea.
We selected cut-points of apnoea hypopnoea index (AHI) of ≥5 and ≥15/h from their home polygraphy and determined associations of these with individual symptoms, questionnaire scores and other results. Receiver operating characteristic analysis and univariate and multivariate logistic regression were used to explore these.
Primary and secondary outcomes measures
Primary: The utility of STOP, STOP-BANG and Berlin Questionnaires for prediction of SDB. Secondary: The utility of other measures for prediction of SDB.
AHI was ≥5 in 97 patients and ≥15 in 56 patients. STOP and STOP-BANG scores were associated with both AHI cut-points but results with ESS and Berlin Questionnaire scores were negative. STOP-BANG had a negative predictive value 1.00 (0.77–1.00) for an AHI ≥15 with a score ≥3 predicting AHI ≥5 with sensitivity 0.93 (95% CI 0.84 to 0.98) and accuracy 79%, while a score ≥6 predicted AHI ≥15 with specificity 0.78 (0.65 to 0.88) and accuracy 72%. Neck circumference ≥17 inch and presence of witnessed apnoeas were independent predictors of SDB.
STOP and STOP-BANG Questionnaires have utility for the prediction of SDB in the sleep clinic population. Modification of the STOP-BANG Questionnaire merits further study in this and other patient groups.
PMCID: PMC4010842  PMID: 24736037
4.  Polysomnography in Patients With Obstructive Sleep Apnea 
Executive Summary
The objective of this health technology policy assessment was to evaluate the clinical utility and cost-effectiveness of sleep studies in Ontario.
Clinical Need: Target Population and Condition
Sleep disorders are common and obstructive sleep apnea (OSA) is the predominant type. Obstructive sleep apnea is the repetitive complete obstruction (apnea) or partial obstruction (hypopnea) of the collapsible part of the upper airway during sleep. The syndrome is associated with excessive daytime sleepiness or chronic fatigue. Several studies have shown that OSA is associated with hypertension, stroke, and other cardiovascular disorders; many researchers believe that these cardiovascular disorders are consequences of OSA. This has generated increasing interest in recent years in sleep studies.
The Technology Being Reviewed
There is no ‘gold standard’ for the diagnosis of OSA, which makes it difficult to calibrate any test for diagnosis. Traditionally, polysomnography (PSG) in an attended setting (sleep laboratory) has been used as a reference standard for the diagnosis of OSA. Polysomnography measures several sleep variables, one of which is the apnea-hypopnea index (AHI) or respiratory disturbance index (RDI). The AHI is defined as the sum of apneas and hypopneas per hour of sleep; apnea is defined as the absence of airflow for ≥ 10 seconds; and hypopnea is defined as reduction in respiratory effort with ≥ 4% oxygen desaturation. The RDI is defined as the sum of apneas, hypopneas, and abnormal respiratory events per hour of sleep. Often the two terms are used interchangeably. The AHI has been widely used to diagnose OSA, although with different cut-off levels, the basis for which are often unclear or arbitrarily determined. Generally, an AHI of more than five events per hour of sleep is considered abnormal and the patient is considered to have a sleep disorder. An abnormal AHI accompanied by excessive daytime sleepiness is the hallmark for OSA diagnosis. For patients diagnosed with OSA, continuous positive airway pressure (CPAP) therapy is the treatment of choice. Polysomnography may also used for titrating CPAP to individual needs.
In January 2005, the College of Physicians and Surgeons of Ontario published the second edition of Independent Health Facilities: Clinical Practice Parameters and Facility Standards: Sleep Medicine, commonly known as “The Sleep Book.” The Sleep Book states that OSA is the most common primary respiratory sleep disorder and a full overnight sleep study is considered the current standard test for individuals in whom OSA is suspected (based on clinical signs and symptoms), particularly if CPAP or surgical therapy is being considered.
Polysomnography in a sleep laboratory is time-consuming and expensive. With the evolution of technology, portable devices have emerged that measure more or less the same sleep variables in sleep laboratories as in the home. Newer CPAP devices also have auto-titration features and can record sleep variables including AHI. These devices, if equally accurate, may reduce the dependency on sleep laboratories for the diagnosis of OSA and the titration of CPAP, and thus may be more cost-effective.
Difficulties arise, however, when trying to assess and compare the diagnostic efficacy of in-home PSG versus in-lab. The AHI measured from portable devices in-home is the sum of apneas and hypopneas per hour of time in bed, rather than of sleep, and the absolute diagnostic efficacy of in-lab PSG is unknown. To compare in-home PSG with in-lab PSG, several researchers have used correlation coefficients or sensitivity and specificity, while others have used Bland-Altman plots or receiver operating characteristics (ROC) curves. All these approaches, however, have potential pitfalls. Correlation coefficients do not measure agreement; sensitivity and specificity are not helpful when the true disease status is unknown; and Bland-Altman plots measure agreement (but are helpful when the range of clinical equivalence is known). Lastly, receiver operating characteristics curves are generated using logistic regression with the true disease status as the dependent variable and test values as the independent variable. Thus, each value of the test is used as a cut-point to measure sensitivity and specificity, which are then plotted on an x-y plane. The cut-point that maximizes both sensitivity and specificity is chosen as the cut-off level to discriminate between disease and no-disease states. In the absence of a gold standard to determine the true disease status, ROC curves are of minimal value.
At the request of the Ontario Health Technology Advisory Committee (OHTAC), MAS has thus reviewed the literature on PSG published over the last two years to examine new developments.
Review Strategy
There is a large body of literature on sleep studies and several reviews have been conducted. Two large cohort studies, the Sleep Heart Health Study and the Wisconsin Sleep Cohort Study, are the main sources of evidence on sleep literature.
To examine new developments on PSG published in the past two years, MEDLINE, EMBASE, MEDLINE In-Process & Other Non-Indexed Citations, the Cochrane Database of Systematic Reviews and Cochrane CENTRAL, INAHTA, and websites of other health technology assessment agencies were searched. Any study that reported results of in-home or in-lab PSG was included. All articles that reported findings from the Sleep Heart Health Study and the Wisconsin Sleep Cohort Study were also reviewed.
Diffusion of Sleep Laboratories
To estimate the diffusion of sleep laboratories, a list of sleep laboratories licensed under the Independent Health Facility Act was obtained. The annual number of sleep studies per 100,000 individuals in Ontario from 2000 to 2004 was also estimated using administrative databases.
Summary of Findings
Literature Review
A total of 315 articles were identified that were published in the past two years; 227 were excluded after reviewing titles and abstracts. A total of 59 articles were identified that reported findings of the Sleep Heart Health Study and the Wisconsin Sleep Cohort Study.
Based on cross-sectional data from the Wisconsin Sleep Cohort Study of 602 men and women aged 30 to 60 years, it is estimated that the prevalence of sleep-disordered breathing is 9% in women and 24% in men, on the basis of more than five AHI events per hour of sleep. Among the women with sleep disorder breathing, 22.6% had daytime sleepiness and among the men, 15.5% had daytime sleepiness. Based on this, the prevalence of OSA in the middle-aged adult population is estimated to be 2% in women and 4% in men.
Snoring is present in 94% of OSA patients, but not all snorers have OSA. Women report daytime sleepiness less often compared with their male counterparts (of similar age, body mass index [BMI], and AHI). Prevalence of OSA tends to be higher in older age groups compared with younger age groups.
Diagnostic Value of Polysomnography
It is believed that PSG in the sleep laboratory is more accurate than in-home PSG. In the absence of a gold standard, however, claims of accuracy cannot be substantiated. In general, there is poor correlation between PSG variables and clinical variables. A variety of cut-off points of AHI (> 5, > 10, and > 15) are arbitrarily used to diagnose and categorize severity of OSA, though the clinical importance of these cut-off points has not been determined.
Recently, a study of the use of a therapeutic trial of CPAP to diagnose OSA was reported. The authors studied habitual snorers with daytime sleepiness in the absence of other medical or psychiatric disorders. Using PSG as the reference standard, the authors calculated the sensitivity of this test to be 80% and its specificity to be 97%. Further, they concluded that PSG could be avoided in 46% of this population.
Obstructive Sleep Apnea and Obesity
Obstructive sleep apnea is strongly associated with obesity. Obese individuals (BMI >30 kg/m2) are at higher risk for OSA compared with non-obese individuals and up to 75% of OSA patients are obese. It is hypothesized that obese individuals have large deposits of fat in the neck that cause the upper airway to collapse in the supine position during sleep. The observations reported from several studies support the hypothesis that AHIs (or RDIs) are significantly reduced with weight loss in obese individuals.
Obstructive Sleep Apnea and Cardiovascular Diseases
Associations have been shown between OSA and comorbidities such as diabetes mellitus and hypertension, which are known risk factors for myocardial infarction and stroke. Patients with more severe forms of OSA (based on AHI) report poorer quality of life and increased health care utilization compared with patients with milder forms of OSA. From animal models, it is hypothesized that sleep fragmentation results in glucose intolerance and hypertension. There is, however, no evidence from prospective studies in humans to establish a causal link between OSA and hypertension or diabetes mellitus. It is also not clear that the associations between OSA and other diseases are independent of obesity; in most of these studies, patients with higher values of AHI had higher values of BMI compared with patients with lower AHI values.
A recent meta-analysis of bariatric surgery has shown that weight loss in obese individuals (mean BMI = 46.8 kg/m2; range = 32.30–68.80) significantly improved their health profile. Diabetes was resolved in 76.8% of patients, hypertension was resolved in 61.7% of patients, hyperlipidemia improved in 70% of patients, and OSA resolved in 85.7% of patients. This suggests that obesity leads to OSA, diabetes, and hypertension, rather than OSA independently causing diabetes and hypertension.
Health Technology Assessments, Guidelines, and Recommendations
In April 2005, the Centers for Medicare and Medicaid Services (CMS) in the United States published its decision and review regarding in-home and in-lab sleep studies for the diagnosis and treatment of OSA with CPAP. In order to cover CPAP, CMS requires that a diagnosis of OSA be established using PSG in a sleep laboratory. After reviewing the literature, CMS concluded that the evidence was not adequate to determine that unattended portable sleep study was reasonable and necessary in the diagnosis of OSA.
In May 2005, the Canadian Coordinating Office of Health Technology Assessment (CCOHTA) published a review of guidelines for referral of patients to sleep laboratories. The review included 37 guidelines and associated reviews that covered 18 applications of sleep laboratory studies. The CCOHTA reported that the level of evidence for many applications was of limited quality, that some cited studies were not relevant to the recommendations made, that many recommendations reflect consensus positions only, and that there was a need for more good quality studies of many sleep laboratory applications.
As of the time of writing, there are 97 licensed sleep laboratories in Ontario. In 2000, the number of sleep studies performed in Ontario was 376/100,000 people. There was a steady rise in sleep studies in the following years such that in 2004, 769 sleep studies per 100,000 people were performed, for a total of 96,134 sleep studies. Based on prevalence estimates of the Wisconsin Sleep Cohort Study, it was estimated that 927,105 people aged 30 to 60 years have sleep-disordered breathing. Thus, there may be a 10-fold rise in the rate of sleep tests in the next few years.
Economic Analysis
In 2004, approximately 96,000 sleep studies were conducted in Ontario at a total cost of ~$47 million (Cdn). Since obesity is associated with sleep disordered breathing, MAS compared the costs of sleep studies to the cost of bariatric surgery. The cost of bariatric surgery is $17,350 per patient. In 2004, Ontario spent $4.7 million per year for 270 patients to undergo bariatric surgery in the province, and $8.2 million for 225 patients to seek out-of-country treatment. Using a Markov model, it was concluded that shifting costs from sleep studies to bariatric surgery would benefit more patients with OSA and may also prevent health consequences related to diabetes, hypertension, and hyperlipidemia. It is estimated that the annual cost of treating comorbid conditions in morbidly obese patients often exceeds $10,000 per patient. Thus, the downstream cost savings could be substantial.
Considerations for Policy Development
Weight loss is associated with a decrease in OSA severity. Treating and preventing obesity would also substantially reduce the economic burden associated with diabetes, hypertension, hyperlipidemia, and OSA. Promotion of healthy weights may be achieved by a multisectorial approach as recommended by the Chief Medical Officer of Health for Ontario. Bariatric surgery has the potential to help morbidly obese individuals (BMI > 35 kg/m2 with an accompanying comorbid condition, or BMI > 40 kg/m2) lose weight. In January 2005, MAS completed an assessment of bariatric surgery, based on which OHTAC recommended an improvement in access to these surgeries for morbidly obese patients in Ontario.
Habitual snorers with excessive daytime sleepiness have a high pretest probability of having OSA. These patients could be offered a therapeutic trial of CPAP to diagnose OSA, rather than a PSG. A majority of these patients are also obese and may benefit from weight loss. Individualized weight loss programs should, therefore, be offered and patients who are morbidly obese should be offered bariatric surgery.
That said, and in view of the still evolving understanding of the causes, consequences and optimal treatment of OSA, further research is warranted to identify which patients should be screened for OSA.
PMCID: PMC3379160  PMID: 23074483
5.  STOP-Bang and the effect on patient outcome and length of hospital stay when patients are not using continuous positive airway pressure 
Journal of Anesthesia  2014;28:891-897.
In patients undergoing surgical interventions under general anesthesia, obstructive sleep apnea syndrome (OSA) can cause serious perioperative cardiovascular or respiratory complications leading to fatal consequences, even sudden death. In this study we test the hypothesis that morbidly obese patients diagnosed by a polysomnography test and using continuous positive airway pressure (CPAP) therapy have fewer and less severe perioperative complications and a shorter hospital stay than patients who have a medical history that meets at least three STOP-Bang criteria and are not using CPAP therapy.
Postoperative hospital stay and pulmonary complications were analyzed in three groups of morbidly obese patients undergoing bariatric surgery (Roux-en-Y gastric bypass and laparoscopic sleeve gastrectomy) between January 2009 and November 2013 (n = 693). Group A comprised 99 patients who were preoperatively diagnosed with OSA based on polysomnography results. These patients used CPAP therapy before and after surgery. Group B consisted of 182 patients who met at least three STOP-Bang criteria but who were not diagnosed with OSA based on polysomnography results. These patients did not use CPAP. Group C, the reference group, comprised 412 patients who scored one to two items on the STOP-Bang.
During the perioperative period, Group B patients had a significantly (p < 0.001) higher cumulative rate of pulmonary complications, worse oxygen saturation, respiratory rates, and increased length of stay in hospital. There was also two cases of sudden death in this group.
Based on these results, we conclude that patients meeting at least three STOP-BANG criteria have higher postoperative complications and an increased length of hospital stay than patients using CPAP.
PMCID: PMC4263911  PMID: 24871541
Obstructive sleep apnea syndrome; Morbid obesity; Postoperative complications; Sudden death
6.  A longitudinal study of CPAP therapy for patients with chronic cough and obstructive sleep apnoea 
Chronic cough patients are rendered therapies for gastro-esophageal reflux (GERD), upper airway cough syndrome (UACS) and cough-variant asthma (CVA) with varying benefit. Idiopathic or unexplained cough has emerged as an important clinical entity in both primary care and subspecialty clinics. Recent evidence points to a link between chronic cough and untreated obstructive sleep apnea (OSA).
A prospective observational study was done to evaluate the effect of OSA therapy in patients with chronic cough. Patients enrolled into the study underwent questionnaires to evaluate for GERD, UACS and CVA along with screening questionnaires for OSA and daytime sleepiness. The Leicester cough questionnaire (LCQ) was done at baseline and during serial visits to evaluate cough intensity and was used as the primary outcome measure of the effect of CPAP therapy on chronic cough.
Out of 37 patients enrolled into the study, only 28 patients had follow up LCQ scores available and therefore underwent analysis. 22/28 patients were suspected to have OSA based on abnormal STOP-BANG screening questionnaire scores and overnight oximetry abnormalities. Of these 19/28 patients had overnight attended polysomnography with definitive diagnosis of OSA yielding a 68% prevalence of OSA in our chronic cough population. Chronic cough patients treated for OSA tended to be older with a significantly higher BMI than chronic cough patients without OSA. Significant improvement of LCQ scores occurred with CPAP therapy for OSA in chronic cough patients.
OSA is significantly prevalent in chronic cough patients. Subjects with chronic cough and OSA tend to be older and obese. Treatment of OSA in chronic cough patients yields significant improvement in their health status.
PMCID: PMC3722026  PMID: 23845135
Cough; Sleep apnea; Obstructive; Continuous positive airway pressure
7.  The Utility of Three Screening Questionnaires for Obstructive Sleep Apnea in a Sleep Clinic Setting 
Yonsei Medical Journal  2015;56(3):684-690.
The aim of this study was to determine the diagnostic value of three screening questionnaires in identifying Korean patients at high risk for obstructive sleep apnea (OSA) in a sleep clinic setting in Korea.
Materials and Methods
Data were collected from 592 adult patients with suspected OSA who visited a sleep center. All patients completed the Sleep Apnea of Sleep Disorder Questionnaire (SA-SDQ), the Berlin questionnaire, and the STOP-Bang questionnaire. Estimated OSA risk was compared to a diagnosis of OSA. The sensitivity, specificity, positive predictive value, and negative predictive value were calculated for each questionnaire.
The prevalence of OSA was 83.6% using an apnea-hypopnea index (AHI) ≥5/h and 58.4% for an AHI ≥15/h. The STOP-Bang questionnaire had a high sensitivity (97% for AHI ≥5/h, 98% for AHI ≥15/h), but the specificity was low (19% and 11%, respectively). In contrast, the sensitivity of the SA-SDQ was not high enough (68% for AHI ≥5/h, 74% for AHI ≥15/h) to be useful in a clinical setting, whereas the specificity was relatively good (66% and 61%, respectively). The sensitivity and specificity values of the Berlin questionnaire fell between those of the STOP-Bang questionnaire and the SA-SDQ.
The STOP-Bang questionnaire may be useful for screening OSA in a sleep clinic setting, but its specificity is lower than the acceptable level for this purpose. A new screening questionnaire with a high sensitivity and acceptable specificity is therefore needed in a sleep clinic setting.
PMCID: PMC4397437  PMID: 25837173
Obstructive sleep apnea; screening questionnaires; sleep disorders
8.  Prevalence and Diagnostic Approach to Sleep Apnea in Hemodialysis Patients: A Population Study 
BioMed Research International  2015;2015:103686.
Background. Previous observations found a high prevalence of obstructive sleep apnea (OSA) in the hemodialysis population, but the best diagnostic approach remains undefined. We assessed OSA prevalence and performance of available screening tools to propose a specific diagnostic algorithm. Methods. 104 patients from 6 Swiss hemodialysis centers underwent polygraphy and completed 3 OSA screening scores: STOP-BANG, Berlin's Questionnaire, and Adjusted Neck Circumference. The OSA predictors were identified on a derivation population and used to develop the diagnostic algorithm, which was validated on an independent population. Results. We found 56% OSA prevalence (AHI ≥ 15/h), which was largely underdiagnosed. Screening scores showed poor performance for OSA screening (ROC areas 0.538 [SE 0.093] to 0.655 [SE 0.083]). Age, neck circumference, and time on renal replacement therapy were the best predictors of OSA and were used to develop a screening algorithm, with higher discriminatory performance than classical screening tools (ROC area 0.831 [0.066]). Conclusions. Our study confirms the high OSA prevalence and highlights the low diagnosis rate of this treatable cardiovascular risk factor in the hemodialysis population. Considering the poor performance of OSA screening tools, we propose and validate a specific algorithm to identify hemodialysis patients at risk for OSA for whom further sleep investigations should be considered.
PMCID: PMC4502277
9.  The Validity and Reliability of an Arabic Version of the STOP-Bang Questionnaire for Identifying Obstructive Sleep Apnea 
Obstructive sleep apnea (OSA) is a common, serious, under-recognized and under-diagnosed medical disorder. Polysomnography (PSG) is the gold standard diagnostic test for OSA; however, the cost of testing and the shortage of sleep disorders laboratories limit access to this tool. Therefore, there is a need for a simple and reliable diagnostic tool to screen patients at risk of OSA.
This study was conducted to evaluate the validity and reliability of an Arabic version of the STOP-Bang questionnaire (SBQ) as a screening tool for OSA.
This study was conducted in three steps, as follows: Step 1: the SBQ was translated from English to Arabic (examining both forward and backward translations); Step 2: the test-retest reliability of the questionnaire was investigated; and Step 3: the questionnaire was validated against PSG data prospectively on 100 patients attending a sleep disorders clinic who were subjected to a full-night PSG study after completing the translated version of the SBQ. The validity of the test was tested against the apnea-hypopnea index (AHI).
The study group had a mean age of 46.6 ± 14.0 years and a mean AHI of 50.0 ± 37.0/hour. The study demonstrated a high degree of internal consistency and stability over time for the translated SBQ. The Cronbach’s alpha coefficient for the 8-item tool was 0.7. Validation of the SBQ against the AHI at a cut-off of 5 revealed a sensitivity of 98% and positive and negative predictive values of 86% and 67%, respectively.
The Arabic version of the SBQ is an easy-to-administer, simple, reliable and valid tool for the identification of OSA in the sleep disorders clinic setting.
PMCID: PMC4378065  PMID: 25834656
Apnea-hypopnea index; STOP-Bang questionnaire; obstructive sleep apnea; validity; reliability; screening; sleepiness
10.  Clinical assessment and polysomnographic study of sleep apnea in a Chinese population of snorers*  
Background and objectives: While an increasing number of people who snore are seeking medical consultations, the clinical characteristics of snorers are rarely reported. The aim of this study is to characterize the clinical and polysomnographic features in a population of snorers. Methods: A total of 490 subjects were examined retrospectively. The clinical history, Epworth Sleepiness Scale (ESS) scores, physical examination, and full-night polysomnography (PSG) data were obtained for all the subjects. The correlations between the neck circumference, waist circumference, ESS scores, body mass index (BMI), and apnea-hypopnea index (AHI) of obstructive sleep apnea (OSA) patients were explored. The gender and age differences in OSA patients were analyzed. Results: OSA was diagnosed in 84.7% of the sample, with 21.2% of the patients having a mild form, 15.4% having a moderate form, and 63.4% having a severe form of OSA. The ESS scores, neck circumference, waist circumference, and BMI were positively correlated with AHI in OSA patients. The ESS scores and BMI were negatively correlated with nadir oxygen saturation (SaO2). A greater number of men than women exhibited moderate to severe forms of the disease. OSA affects the work of males more commonly compared with females. Nocturia was a more common complaint in elderly OSA patients. Heart diseases coexisted more frequently with OSA in elderly patients. Conclusions: In a population of snorers, OSA is the most common condition identified. The ESS scores and BMI were well correlated with the severity of the disease. Men had a more severe form of OSA than women. Nocturia frequently occurred in elderly OSA patients, as did the coexistence of heart disease.
PMCID: PMC4357371  PMID: 25743123
Obstructive sleep apnea; Gender; Elderly; Hypoxia; Snoring
11.  Do Patients with Obstructive Sleep Apnea have an Increased Risk of Desaturation During Induction of Anesthesia for Weight Loss Surgery? 
Obstructive sleep apnea (OSA) is an independent risk factor to develop perioperative complications during weight loss surgery, but the mechanisms are unclear. It is possible, that patients with OSA have a higher incidence of desaturation during induction of anesthesia.
We enrolled 100 morbidly obese (body mass index: 53±10) adult patients undergoing open bariatric surgery in a prospective study. At least 1 h before induction of anesthesia, peripheral oxygen saturation (SpO2) was measured by an oximetry finger probe in the sitting and supine positions, and Mallampati score was taken. Oxygen saturation was recorded also during induction of anesthesia, and nadir values were analyzed, and the STOP-BANG questionnaire was applied.
Thirty-six patients presented with clinical suspicion of OSA. Body weight predicted oxygen saturation in the supine and sitting position, prior to induction of anesthesia. Nadir oxygen saturation during induction of anesthesia was considerably higher in patients with clinical suspicion of OSA, a significant finding that persisted as a trend after correction for age, gender and BMI. The Mallampati score was an independent predictor of OSA, even in morbidly obese patients scheduled for weight loss surgery.
Morbidly obese patients presenting for weight loss surgery have a significant risk to desaturate during induction of anesthesia. A history of OSA does not independently increase the risk of desaturation during induction of anesthesia, if the appropriate precautions are being taken.
PMCID: PMC2928890  PMID: 20802806
Obstructive sleep apnea; obesity; bariatric surgery; oximetry; anesthesia.
12.  Rhythm disturbances in childhood obstructive sleep apnea during apnea-hypopnea episodes 
Obstructive sleep apnoea (OSA) can result in cardiovascular complications. Nocturnal arrhythmias are reported up to 50% of adult OSA patients. Arrhythmias and heart rate variability in children with OSA have not been well studied.
We sought to study rhythm disturbances in childhood OSA and also to analyze the relationship of heart rate variability to the severity of OSA in children.
In a retrospective cross sectional study, records of children aged < 15 years with history of snoring and suspected OSA, who had undergone polysomnography (PSG) for first time were analyzed. The cardiac rhythm and heart rate variability were studied during PSG.
A total of 124 patients diagnosed with OSA were grouped into mild (n = 52), moderate (n = 30), and severe (n = 42) OSA. During PSG, all had sinus arrhythmias and only three patients had premature atrial contractions (PACs). The standard deviation of heart rate (SD-HR) during rapid eye movement (REM) sleep in severe OSA (9.1 ± 2.4) was significantly higher than SD-HR in mild OSA (7.5 ± 1.3, P < 0.0001). The maximum heart rate (max-HR) during REM-sleep in severe OSA (132.1 ± 22.1) was significantly higher than the max-HR in mild OSA (121.3 ± 12.6 bpm, P = 0.016).
There was no significant arrhythmia in children with OSA during their sleep. Heart rate variability correlated with the severity of OSA.
PMCID: PMC3634245  PMID: 23626434
Arrhythmia; children; obstructive sleep apnea
13.  Prevalence of obstructive sleep apnea in surgical patients presenting to a tertiary care teaching hospital in India: A preliminary study 
Saudi Journal of Anaesthesia  2013;7(2):155-159.
Obstructive sleep apnea (OSA) is often not diagnosed in patients presenting for surgical procedures thereby increasing the incidence of adverse perioperative course. Early diagnosis of this disease is important in modifying anesthetic management as well as utilizing specific means which may decrease the complications and improve the patient outcome.
Patients greater than eighteen years of age, ASA I-III scheduled for elective surgical procedures under anesthesia were randomly selected. Their demographic data, diagnosis and nature of surgery were noted in a semi-structured performa. They were then screened for the presence of OSA with the help of a STOP BANG questionnaire.
This study included two hundred four patients randomly selected. Slight female predominance was seen in this sample (55.4%). Mean age of the subjects was 42.7 years (SD=15.08). 24.5% subjects were at high risk for OSA (STOP-BANG>3) with a male predominance (72% versus 37% in low risk group; X2=18.62; P<0.001). High risk OSA subjects had higher prevalence of cardiovascular risk factors (57% vs. 11.7% in low risk group; X2=33.35; P<0.001). Similarly, this group had a higher prevalence of asthma and chronic obstructive pulmonary disease (COPD) (14% versus 3.8% in low risk group; X2=6.54; P=0.03). Prevalence of diabetes mellitus (22%) and hypothyroidism (6%) was also higher in this group (5.2% and 1.9% in low risk group respectively; X2=15.42; P<0.001).
High degree of suspicion and knowledge of association of OSA and medical diseases may help in detection of such cases and decrease the rate of perioperative complications thus improving patients safety.
PMCID: PMC3737691  PMID: 23956715
Anaesthesia; complication; obstructive sleep apnea; STOP BANG
14.  Perioperative management and complications in patients with obstructive sleep apnea undergoing transsphenoidal surgery: Our institutional experience 
Background and Aims:
Patients with endocrine diseases such as acromegaly and Cushing's disease have a high prevalence of obstructive sleep apnea (OSA). There is controversy regarding the use of continuous positive airway pressure (CPAP) following transsphenoidal surgery. The aim of this study was to compare the perioperative management and complications, in patients with or without OSA undergoing transsphenoidal surgery.
Materials and Methods:
After Research Ethics Board approval, we retrospectively reviewed the charts of all patients who underwent transsphenoidal surgery in our institution from 2006 to 2011. Information collected included patients’ demographics, pathology of lesion, history of OSA, anesthetic and perioperative management and incidence of perioperative complications. Patients with sleep study proven OSA were compared with a control group, matched for age, sex and pathology of patients without OSA. Statistical analysis was performed using t-test and Chi-square test and the P < 0.05 was considered to be significant.
Out of a total 469 patients undergoing transsphenoidal surgery, 105 patients were found to be at risk for OSA by a positive STOP-BANG scoring assessment. Preoperative sleep study testing was positive for OSA in 38 patients. Post-operative hypoxemia (SpO2 < 90) occurred in 10 (26%) patients with OSA and was treated with high-flow oxygen through face mask (n = 7) and by CPAP mask (n = 3). In the OSA-negative group, 2 patients had hypoxemia and were treated with low-flow oxygen using face mask. There were no differences between the groups with respect to post-operative opioid use, destination, hospital stay or other complications.
Post-operative hypoxemia in patients with OSA following transsphenoidal surgery can be treated in most but not all patients with high flow oxygen using the face mask. We were able to safely use CPAP in a very small number of patients but caution is needed to prevent complications. Further prospective studies are needed to determine the safe use of CPAP in patients after transsphenoidal surgery.
PMCID: PMC4152674  PMID: 25190942
Continuous positive airway pressure; obstructive sleep apnea; transsphenoidal surgery
15.  High-risk of obstructive sleep apnea and excessive daytime sleepiness among commercial intra-city drivers in Lagos metropolis 
The burden of obstructive sleep apnea among commercial drivers in Nigeria is not known.
To assess the prevalence of high risk of obstructive sleep apnea (OSA) and excessive daytime sleepiness (EDS) among intra-city commercial drivers.
Setting and Design:
A descriptive cross-sectional study in three major motor parks in Lagos metropolis.
Materials and Methods:
Demographic, anthropometric and historical data was obtained. The risk of OSA and EDS was assessed using the STOP BANG questionnaire and the Epworth Sleepiness Scale, respectively.
Statistical Analysis:
The relationship between the OSA risk, EDS risk and past road traffic accident (RTA) was explored using the Pearson's chi square. Independent determinants of OSA risk, EDS risk and past RTA, respectively, were assessed by multiple logistic regression models.
Five hundred male commercial drivers (mean age (years) ±SD = 42.36 ± 11.17 and mean BMI (kg/m2) ±SD = 25.68 ± 3.79) were recruited. OSA risk was high in 244 (48.8%) drivers and 72 (14.4%) had EDS. There was a positive relationship between OSA risk and the risk of EDS (Pearson's X2 = 28.2, P < 0.001). Sixty-one (12.2%) drivers had a past history of RTA but there was no significant relationship between a past RTA and either OSA risk (X2 = 2.05, P = 0.15) or EDS risk (X2 = 2.7, P = 0.1), respectively. Abdominal adiposity, regular alcohol use and EDS were independent determinants of OSA risk while the use of cannabis and OSA risk were independent determinants of EDS. No independent risk factor for past RTA was identified.
A significant proportion of commercial drivers in Lagos metropolis are at high risk of OSA and EDS.
PMCID: PMC3821221  PMID: 24249946
Commercial drivers; excessive day time sleepiness; Lagos; obstructive sleep apnea
16.  Neck circumference, metabolic syndrome and obstructive sleep apnea syndrome; Evaluation of possible linkage 
This study was performed to evaluate neck circumference (NC) and metabolic syndrome (MS) parameters in severe and non-severe (mild-moderate) obstructive sleep apnea syndrome (OSAS) patients according to apnea-hypopnea index (AHI).
We enrolled 44 patients diagnosed with OSAS based on overnight polysomnography. The diagnosis of OSAS was based on AHI. Apnea is a pause of airflow for more than 10 seconds. and hypopnea is a decrease of airflow for more than 10 seconds and oxygen desaturation of 4% or greater. AHI score. per hour; below 5 normal. 5–29 mild-moderate. 30 and above were grouped as severe OSAS. Height. weight. neck circumference (NC). waist circumference (WC) and body mass index (BMI) of the patients were measured. MS was diagnosed by the Adult Treatment Panel (ATP) III criteria (≥3 of the following abnormalities): 1) WC ≥94 cm for males, ≥80 cm for females; 2) arterial blood pressure ≥130/85 mmHg; 3) fasting blood glucose ≥100 mg/dl; 4) high density lipoprotein (HDL) cholesterol <40 mg/dl in man, <50 mg/dl in women; 5) triglycerides ≥150 mg/dl.
Mean BMI and NC were higher in severe OSAS patients compared to non-severe patients (p=0.021. p<0.001). According to ATP III criteria. 64% of severe and 61.1% of non-severe OSAS patients were MS (p=0.847). A logistic regression model displayed an association with NC as a risk factor for severe OSAS (p=0.01). but not with MS.
In this study. NC in severe OSAS patients was significantly higher than in non-severe OSAS patients. The prevalence of metabolic syndrome was not correlated with OSAS severity. NC is an independent risk factor for severe OSAS.
PMCID: PMC3628860  PMID: 23403781
neck circumference; metabolic syndrome; obstructive sleep apnea syndrome; apnea-hypopnea index
17.  Quality of life impairment in patients of obstructive sleep apnea and its relation with the severity of disease 
Several studies have demonstrated considerable impairment of quality of life (QOL) in obstructive sleep apnea (OSA) patients, but its relation with severity of OSA is yet unclear.
Study Objectives:
To investigate the effects of OSA on the QOL and its association with the disease severity.
Design and Setting:
Observational, prospective case-control study.
Materials and Methods:
QOL of 69 OSA patients and 41 healthy controls were assessed using the Calgary sleep apnea quality of life index (SAQLI) on the morning following the polysomnography (PSG) study.
All statistical analyses were performed using the SPSS 17.0 (SPSS Inc., Chicago). Differences between sleep-related symptoms and SAQLI subscales scores were assessed with the Chi-square test and the Student t-test. Due to non-normal distribution, differences between SAQLI scores of controls and OSA patients were evaluated using a non-parametric Mann-Whitney test. Spearman correlation and backward multiple regression analysis were used to analyze the association between SAQLI scores and sleep indices and anthropometric variables and PSG variables.
Study included 69 cases (57 male and 12 females) with a mean age, weight, height, neck circumference, and body mass index 48.45 ± 10.12 years, 83.03 ± 16.48 kg, 159.75 ± 28.29 cm, 44.01 ± 3.23 cm and 30.77 ± 6.71 kg/m2. Mean apnea-hypopnea index was 26.39 ± 16.62. The median score of four SAQLI domains daily function, social interaction, emotional, symptoms and total mean SAQLI score were 3.64 (3.46-3.90), 3.77 (3.51-3.88), 3.64 (3.53-3.83), 4.80 (4.68-5.11), 4.09 (3.88-4.09),and 1.36 (1.29-1.71), 1.38 (1.24-1.62), 1.45 (1.23-1.62), 2.00 (1.78-2.26), 1.55 (1.46-1.73) for patients and controls respectively. All the individual domain scores and the mean SAQLI scores of patients were significantly higher than the controls.
OSA causes significant impairment of QOL, but the severity of impairment is not directly proportional to the severity of OSA.
PMCID: PMC3841684  PMID: 24339485
Apnea; obstructive sleep; quality of life; sleep apnea quality of life index
18.  Validation of overnight oximetry to diagnose patients with moderate to severe obstructive sleep apnea 
Polysomnography (PSG) is treated as the gold standard for diagnosing obstructive sleep apnea (OSA). However, it is labor-intensive, time-consuming, and expensive. This study evaluates validity of overnight pulse oximetry as a diagnostic tool for moderate to severe OSA patients.
A total of 699 patients with possible OSA were recruited for overnight oximetry and PSG examination at the Sleep Center of a University Hospital from Jan. 2004 to Dec. 2005. By excluding 23 patients with poor oximetry recording, poor EEG signals, or respiratory artifacts resulting in a total recording time less than 3 hours; 12 patients with total sleeping time (TST) less than 1 hour, possibly because of insomnia; and 48 patients whose ages less than 20 or more than 85 years old, data of 616 patients were used for further study. By further considering 76 patients with TST < 4 h, a group of 540 patients with TST ≥ 4 h was used to study the effect of insufficient sleeping time. Alice 4 PSG recorder (Respironics Inc., USA) was used to monitor patients with suspected OSA and to record their PSG data. After statistical analysis and feature selection, models built based on support vector machine (SVM) were then used to diagnose moderate and moderate to severe OSA patients with a threshold of AHI = 30 and AHI = 15, respectively.
The SVM models designed based on the oxyhemoglobin desaturation index (ODI) derived from oximetry measurements provided an accuracy of 90.42-90.55%, a sensitivity of 89.36-89.87%, a specificity of 91.08-93.05%, and an area under ROC curve (AUC) of 0.953-0.957 for the diagnosis of severe OSA patients; as well as achieved an accuracy of 87.33-87.77%, a sensitivity of 87.71-88.53%, a specificity of 86.38-86.56%, and an AUC of 0.921-0.924 for the diagnosis of moderate to severe OSA patients. The predictive outcome of ODI to diagnose severe OSA patients is better than to diagnose moderate to severe OSA patients.
Overnight pulse oximetry provides satisfactory diagnostic performance in detecting severe OSA patients. Home-styled oximetry may be a tool for severe OSA diagnosis.
PMCID: PMC4407425  PMID: 25880649
Obstructive sleep apnea (OSA); Oximetry; Support vector machine (SVM); Polysomnography (PSG)
19.  Reactive Oxygen Species Production in Peripheral Blood Neutrophils of Obstructive Sleep Apnea Patients 
The Scientific World Journal  2013;2013:421763.
Obstructive sleep apnea (OSA) as well as obesity is associated with increased production of reactive oxygen species (ROS). Neutrophils produce great amounts of ROS. The aim was to evaluate peripheral blood neutrophils ROS production in men with OSA and to establish relations with disease severity and obesity. Methods. Forty-six men with OSA and 10 controls were investigated. OSA was confirmed by polysomnography (PSG), when apnea/hypopnea index was >5/h. Body mass index (BMI) was evaluated. Neutrophils were isolated from peripheral blood in the morning after PSG. Dihydrorhodamine-123 was used for ROS detection. Data is presented as median (25th and 75th percentiles). All subjects were divided into four groups: nonobese mild-to-moderate OSA, obese mild-to-moderate OSA, nonobese severe OSA, and obese severe OSA. Results. Neutrophil ROS production was higher in nonobese severe OSA group compared to nonobese mild-to-moderate OSA (mean fluorescence intensity (MFI) 213.4 (89.0–238.9) versus 44.5 (20.5–58.4), P < 0.05). In obese patient groups, ROS production was more increased in severe OSA compared to mild-to-moderate OSA group (MFI 74.5 (47.9–182.4) versus 31.0 (14.8–53.8), P < 0.05). It did not differ in the groups with different BMI and the same severity of OSA. Conclusion. Increased neutrophil ROS production was related to more severe OSA but not obesity.
PMCID: PMC3666210  PMID: 23766689
20.  Prospective assessment of the risk of obstructive sleep apnea in patients attending a tertiary health facility in Sub-Saharan Africa 
The impact of Obstructive sleep apnea (OSA) in worsening outcomes is profound, especially in the presence of comorbid conditions. This study aimed to describe the proportion of patients at a high risk of OSA in our practice setting.
The STOP BANG questionnaire and the Epworth Sleepiness scale were used to assess for OSA risk and excessive daytime sleepiness respectively. Hospitalized patients and out-patients were recruited. Intergroup differences in continuous variables were compared using the analysis of variance. The proportion of patients with high risk of OSA and excessive daytime sleepiness was presented as frequencies and group differences compared with the Pearson χ2 test. Independent risk predictors for OSA were assessed in multivariate logistic regression analysis.
A total of 1100 patients (53.4% females) participated in the study. Three hundred and ninety nine (36.3%) had a high risk of OSA, and 268 (24.4%) had excessive daytime sleepiness. Of the participants with high OSA risk, 138 (34.6%) had excessive daytime sleepiness compared to 130 (18.5%) of those with low OSA risk (p).
A significant proportion of patients attending our tertiary care center are at high risk of OSA.
PMCID: PMC4198286  PMID: 25328598
Obstructive sleep apnea; excessive day time sleepiness; tertiary hospital; Nigeria
21.  Cardiovascular risk markers in obstructive sleep apnoea syndrome and correlation with obesity 
Thorax  2007;62(6):509-514.
High C‐reactive protein (CRP) and homocysteine levels are risk factors for cardiovascular disease. Some, but not all, previous studies have reported increased levels of CRP and homocysteine in patients with obstructive sleep apnoea syndrome (OSAS). A study was undertaken to investigate the levels of these factors in carefully selected patients with OSAS and matched normal controls.
CRP and homocysteine levels were measured in 110 subjects following polysomnography (PSG). Non‐OSAS patients (group 1) were compared with two patient groups (mild/moderate OSAS (group 2) and severe OSAS (group 3)) group‐matched for body mass index (BMI), and a fourth group of patients with severe OSAS who were more obese (group 4). All were free of other disease and similar in age, smoking habits and cholesterol levels. 50 suitable patients were commenced on continuous positive airway pressure (CPAP) treatment after PSG and 49 were reassessed 6 weeks later.
CRP levels were similar in groups 1, 2 and 3 (median (interquartile range (IQR)) 1.11 (0.76–2.11) mg/l vs 1.82 (1.20–3.71) mg/l vs 2.20 (1.16–3.59) mg/l; p = 0.727, Kruskal‐Wallis test), but were significantly higher in group 4 than in the other groups (5.36 (2.42–9.17) mg/l, p<0.05 by individual group comparisons). In multivariate analysis of all subjects, BMI was an independent predictor for CRP levels (β = 0.221; p = 0.006) but apnoea‐hypopnoea index and other measures of OSAS were not. There was no difference in homocysteine levels between all four groups (p = 0.1). CPAP did not alter CRP (2.29 (1.32–4.10) vs 2.84 (1.13–5.40) mg/l; p = 0.145) or homocysteine levels (8.49 (3.66) vs 9.90 (4.72) μmol/l; p = 0.381).
CRP and homocysteine levels are not associated with OSAS severity in men but CRP is independently associated with obesity.
PMCID: PMC2117225  PMID: 17251313
22.  Clinical Characteristics, Comorbidities, and Response to Treatment of Veterans With Obstructive Sleep Apnea, Cincinnati Veterans Affairs Medical Center, 2005-2007 
Obstructive sleep apnea (OSA) is a common disorder that is associated with significant morbidity. Veterans may be at an elevated risk for OSA because of increased prevalence of factors associated with the development and progression of OSA. The objective of this study was to determine the clinical characteristics, comorbidities, polysomnographic findings, and response to treatment of veterans with OSA.
We performed a retrospective chart review of 596 patients undergoing polysomnography at the Cincinnati Veterans Affairs Medical Center from February 2005 through December 2007. We assessed potential correlations of clinical data with polysomnography findings and response to treatment.
Polysomnography demonstrated OSA in 76% of patients; 30% had mild OSA, 23% moderate OSA, and 47% severe OSA. Increasing body mass index, neck circumference, Epworth Sleepiness Scale score, hypertension, congestive heart failure, and type 2 diabetes correlated with increasing OSA severity. Positive airway pressure treatment was initiated in 81% of veterans with OSA, but only 59% reported good adherence to this treatment method. Of the patients reporting good adherence, a greater proportion of those with severe OSA (27%) than with mild or moderate disease (0%-12%) reported an excellent response to treatment.
The prevalence of metabolic and cardiovascular comorbidities increased with increasing OSA severity. Only 59% of treated patients reported good adherence to treatment with positive airway pressure, and response to treatment correlated with OSA severity.
PMCID: PMC3337849  PMID: 22280961
23.  Prevalence of metabolic syndrome in a north Indian hospital-based population with obstructive sleep apnoea 
Background & objectives:
Obstructive sleep apnoea (OSA) is known to be associated with cardiovascular risk factors and metabolic syndrome (MS). The burden of MS in patients with OSA in India is unknown. We investigated the prevalence of MS and its components in a cross-sectional study in patients with and without OSA in a hospital-based population of a tertiary health care centre in New Delhi, India.
Consecutive patients undergoing overnight polysomnography in the Sleep Laboratory of the Department of Internal Medicine of All India Institute of Medical Sciences (AIIMS) hospital, New Delhi, were studied. Anthropometry and body composition analysis, blood pressure (BP), fasting blood glucose, insulin resistance by homeostasis model assessment (HOMA-IR) and fasting blood lipid profile were measured. MS was defined using the National Cholesterol Education Program Adult treatment panel III criteria, with Asian cut-off values for abdominal obesity.
Of the 272 subjects recruited, 187 (82%) had OSA [apnoea-hypopnoea index (AHI)>5 events/h] while 40 (18%) had a normal sleep study. Prevalence of MS in OSA patients was 79 per cent compared to 48 per cent in non-OSA individuals [OR 4.15, (2.05-8.56), P<0.001]. Prevalence of OSA in mild, moderate and severe OSA was 66, 72 and 86 per cent, respectively (P<0.001). Patients with OSA were more likely to have higher BP [OR: 1.06 (1.02-1.11)], fasting insulin [OR: 1.18 (1.05-1.32)], HOMA-IR [OR: 1.61 (1.11-2.33)] and waist circumference [OR: 1.20 (1.13-1.27)].
Interpretation & conclusions:
Our findings suggest that OSA is associated with a 4-fold higher occurrence of MS than patients without OSA. The prevalence of MS increases with increasing severity of OSA, therefore, early detection will be beneficial.
PMCID: PMC3249961  PMID: 22199102
Metabolic syndrome; obstructive sleep apnoea; prevalence; risk factors; South Asians; urban Indians
24.  The correlation of anxiety and depression with obstructive sleep apnea syndrome 
Obstructive sleep apnea syndrome (OSAS) is a common sleep disorder characterized by repeated upper airway obstruction during sleep. While respiratory pauses followed by loud snoring and daytime sleepiness are the main symptoms of OSAS, the patients may complain from sleep disruption, headache, mood disturbance, irritability, and memory impairment. However, the association of sleep apnea with anxiety and depression is not completely understood. Adherence to continuous positive airway pressure (CPAP), the treatment of choice for OSAS, may be influenced by psychological conditions, especially claustrophobia. The aim of this study was to evaluate the association of OSAS with anxiety and depression symptoms. This study also investigated the association of anxiety with body mass index (BMI) and the severity of OSAS.
Materials and Methods:
We conducted a cross-sectional study on 178 adult individuals diagnosed with OSAS at the sleep laboratory between September 2008 and May 2012. The participants were interviewed according to a checklist regarding both their chief complaints and other associated symptoms. The psychological status was assessed according to Beck anxiety inventory (BAI) and Beck depression inventory (BDI) scoring. The severity of breathing disorder was classified as mild, moderate, and severe based on apnea–hypopnea index (AHI) which was ascertained by overnight polysomnography. Daytime sleepiness was assessed by Epworth sleepiness scale (ESS).
The mean (SD) age of participants was 50.33 years. In terms of sex, 85.5% of the study population were males and14.4% were females. We found no relation between sex and the symptoms of OSAS. Regarding the frequency of anxiety and depression symptoms, 53.9% of the individuals had some degree of anxiety, while 46.1% demonstrated depressive symptoms. In terms of OSAS severity, this study showed that OSAS severity was associated with the frequency of anxiety, chocking, and sleepiness (P : 0.001). According to polysomnographic results, we found that the majority of patients suffering from anxiety and chocking (66.7% and 71.4%, respectively) had severe OSAS, while only 23.1% of patients with sleepiness had severe OSAS.
Our study showed that the frequency of anxiety in OSAS patients is higher than in the general population regardless of the gender. Furthermore, it is more likely that OSAS patients present with anxiety and depression than the typical symptoms.
PMCID: PMC4061640  PMID: 24949026
Anxiety; depression; obstructive sleep apnea syndrome
25.  An empirical continuous positive airway pressure trial for suspected obstructive sleep apnea 
Standard practice in obstructive sleep apnea (OSA) management requires that a positive diagnostic, overnight polysomnography (PSG) test be obtained before initiating treatment. However, long waiting times due to lack of access to PSG testing facilities may delay the initiation of definitive treatment for OSA.
To evaluate the response of patients who had a high clinical suspicion for OSA and who were waiting for a PSG test to an empirical continuous positive airway pressure (CPAP) trial.
A retrospective study of all patients who had been offered empirical CPAP therapy for suspected OSA was conducted. After outpatient assessment, 183 patients with a high pretest probability of having OSA began empirical CPAP testing using an arbitrary CPAP pressure. The presence of OSA, the accuracy of empirical CPAP pressure prescription, the adherence to empirical CPAP and the improvement in daytime somnolence were evaluated at the time of PSG.
Of 183 patients on a CPAP trial, 91% had OSA, which was at least moderate (more than 15 apneas and hypopneas per hour of sleep) in 75% of the patients. Eighty per cent of the patients had significant daytime somnolence (Epworth Sleepiness Scale [ESS] greater than 10, mean ± SD ESS 14±5), which improved with CPAP (ESS 9.0±5, P<0.01). In 40% of the patients, the arbitrary CPAP pressure was lower than that determined by manual titration. Adherence to a trial of CPAP (longer than 2 h/night) predicted OSA with a sensitivity of 82% and a specificity of 41%; the positive and negative predictive values were 92% and 22%, respectively.
At the time of PSG testing, OSA was present in 91% of the patients who had received empirical CPAP. An empirical CPAP provided satisfactory interim treatment for excessive somnolence, despite the fact that the CPAP pressure was suboptimal in 40% of the patients.
PMCID: PMC2676837  PMID: 17464380
Continuous positive airway pressure; CPAP responsiveness; CPAP trial; Empirical CPAP; Obstructive sleep apnea

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