Independent Predictor Of Obstructive Sleep Apnea Research Articles

Association of Obstructive Sleep Apnea and Atrial Fibrillation in Acute Ischemic Stroke: A Cross-Sectional Study

Background: There is a growing body of evidence suggesting a link between obstructive sleep apnea (OSA) and atrial fibrillation (AF). The primary objective of this study is to evaluate the association between OSA and AF in acute ischemic stroke. The secondary objective is to describe the clinical features of patients with acute ischemic stroke and concomitant OSA. Methods: We enrolled consecutive patients with acute ischemic stroke. All patients underwent full-night cardiorespiratory polygraphy. To determine if there is an association between AF and OSA, we compared the observed frequency of this association with the expected frequency from a random co-occurrence of the two conditions. Subsequently, patients with and without OSA were compared. Results: A total of 174 patients were enrolled (mean age 67.3 ± 11.6 years; 95 males). OSA and AF were present in 89 and 55 patients, respectively. The association OSA + AF was observed in 33/174 cases, which was not statistically different compared to the expected co-occurrence of the two conditions. Patients with OSA showed a higher neck circumference and body mass index, a higher prevalence of hypertension and dysphagia, and a higher number of central apneas/hypoapneas. In the multivariate analysis, dysphagia and hypertension were independent predictors of OSA. A positive correlation was observed between OSA severity, BMI, and neck circumference. The number of central apneas/hypoapneas was positively correlated with stroke severity. Conclusions: Our data suggest that OSA and AF are highly prevalent but not associated in acute stroke. Our findings support the hypothesis that OSA acts as an independent risk factor for stroke.

Prevalence, clinical characteristics, and predictors of sleep disordered breathing in hospitalized heart failure patients.

Heart failure (HF) is often comorbid with sleep disordered breathing (SDB). This prospective study investigated the prevalence, clinical characteristics, and predictors of SDB in hospitalized HF patients. Sleep studies were performed on hospitalized HF patients from January 2015 to February 2019. SDB was categorized as no/mild SDB, obstructive sleep apnea (OSA), and central sleep apnea (CSA). The study included 1069 hospitalized HF patients. The prevalence rates of OSA and CSA were 16.6% and 36.9%, respectively. Patients with OSA or CSA were more likely to be male and have a higher body mass index (BMI) and more comorbidities. Multivariate logistic regression analysis showed that male sex (odds ratio [OR] = 1.803, 95% confidence interval [CI] = 1.099-2.958), BMI (per 5 kg/m2 increase: OR = 2.270, 95% CI = 1.852-2.783), hypertension (OR = 2.719, 95% CI = 1.817-4.070), diabetes (OR = 1.477, 95% CI = 1.020-2.139), and left ventricular ejection fraction (LVEF) (per 5% increase, OR = 1.126, 95% CI = 1.053-1.204) were independent predictors of OSA. Male sex (OR = 1.699, 95% CI = 1.085-1.271), age (per 10 years, OR = 1.235, 95% CI = 1.118-1.363), heart rate (per 10 bpm, OR = 1.174, 95% CI = 1.099-2.958), LVEF (per 5% increase, OR = 0.882, 95% CI = 0.835-0.932), NT-proBNP (lnNT-proBNP, OR = 1.234, 95% CI = 1.089-1.398) and hypocapnia (OR = 1.455, 95% CI = 1.105-1.915) were independent predictors of CSA. The areas under the receiver operating characteristic curves were 0.794 (95% CI = 0.758-0.830) and 0.673 (95% CI = 0.640-0.706), respectively. More than half of hospitalized HF patients had OSA or CSA, and CSA was the predominant type. OSA and CSA predictors differ. The clinical characteristics of HF patients can help make preliminary predictions for SDB patients.

Neutrophil-to-Lymphocyte Ratio Facilitates Identification of Obstructive Sleep Apnea in Patients with Type B Aortic Dissection.

Purpose To determine whether the neutrophil-to-lymphocyte ratio (NLR) aids in the detection of obstructive sleep apnea (OSA) in patients with type B aortic dissection (TBAD). Methods 324 patients with TBAD or type B aortic intramural hematoma (TB-AIMH) underwent an overnight sleep study. We divided the eligible 256 studied subjects into three groups: group A (n = 109, TBAD patients with OSA), group B (n = 68, TB-AIMH patients with OSA), and group C (n = 79, TBAD patients without OSA). Baseline characteristics, biochemical and sleep parameters, and STOP-Bang questionnaire scores were collected. To assess the predictive efficacy of potential variables, multivariate logistic regression analysis and receiver operating characteristic (ROC) curves were used. Results The study found that about 58% of TBAD patients and 54% of TB-AIMH patients had OSA, a majority of whom had moderate to severe OSA (95.41% and 89.71%, respectively). In the comparison of sleep parameters between patients with TBAD and TB-AIMH, no other than apnea and hypopnea index (AHI) made a significant difference. The multivariate logistic regression analysis showed that neutrophil-to-lymphocyte ratio (NLR) (odds ratio (OR): 3.614, 95% confidence interval (CI): 2.273–5.748, and P < 0.05) and STOP-Bang scores (OR: 1.97, 95% CI: 1.34–2.90, and P < 0.05) were both independent predictors for OSA in patients with TBAD. ROC curves showed NLR had higher sensitivity (65% versus 59%) and specificity (86% versus 57%) for OSA than the STOP-Bang questionnaire. Furthermore, NLR was positively correlated with AHI through the Spearman test (r = 0.398 and P < 0.05). Conclusion NLR was an independent predictor of OSA in TBAD patients with higher sensitivity and specificity than the STOP-Bang questionnaire, and it was positively associated with AHI. NLR may aid in the diagnosis and risk stratification of OSA in TBAD patients.

Two effective clinical prediction models to screen for obstructive sleep apnoea based on body mass index and other parameters.

The diagnosis of obstructive sleepapnea(OSA) relies on polysomnography which is time-consuming and expensive. We therefore aimed to develop two simple, non-invasive models to screen adults for OSA. The effectiveness of using body mass index (BMI) and a new visual prediction model to screenfor OSA was evaluated using a development set (1769 participants) and confirmed using an independent validation set (642 participants). Based on the development set, the best BMI cut-off value for diagnosing OSA was 26.45 kg/m2, with an area under the curve (AUC) of 0.7213 (95% confidence interval (CI), 0.6861-0.7566), a sensitivity of 57% and a specificity of 78%. Through forward conditional logistic regression analysis using a stepwise selection model developed from observed data, seven clinical variables were evaluated as independent predictors of OSA: age, BMI, sex, Epworth Sleepiness Scale score, witnessed apnoeas, dry mouth and arrhythmias. With this new model, the AUC was 0.7991 (95% CI, 0.7668-0.8314) for diagnosing OSA (sensitivity, 75%; specificity, 71%). The results were confirmed using the validation set. A nomogram for predicting OSA was generated based on this new model using statistical software. BMI can be used as an indicatorto screen for OSA in the community. We created an internally validated, highly distinguishable, visual and parsimonious prediction model comprising BMI and other parameters that can be used to identify patients withOSA among outpatients. Use of this prediction model may help to improve clinical decision-making.

Obstructive sleep apnea during rapid eye movement sleep in patients after percutaneous coronary intervention: a multicenter study.

Obstructive sleep apnea (OSA) during the rapid eye movement (REM) stage of the sleep cycle is associated with intense hypoxemia and cardiovascular instability. We characterized OSA during REM sleep in patients after percutaneous coronary intervention. In this multicenter study, 204 patients who had undergone percutaneous coronary intervention in the prior 6 to 36months were recruited for in-laboratory polysomnography. The primary measure was respiratory events during REM sleep. The patients were divided into 2 groups: (1) OSA during REM sleep (≥ 15 events/h) and (2) absence of OSA during REM sleep (< 15 events/h). Based on the overall apnea-hypopnea index ≥ 15, 148 patients (74.0%) had OSA. After excluding patients with failed polysomnography or REM sleep < 30min, 163 patients formed the cohort for this analysis. OSA during REM sleep was diagnosed in 132 patients (81%). Compared with the patients without OSA during REM sleep, those with OSA during REM sleep had a higher body mass index (p = 0.003) and systolic blood pressure (p = 0.041), and a higher prevalence of diabetes mellitus (p = 0.029). Logistic regression analysis, including age, sex, diabetes mellitus, indication for percutaneous coronary intervention, and indication for multi-vessel percutaneous coronary intervention, showed that diabetes mellitus was the only independent predictor of OSA during REM sleep (odds ratio 2.83; 95% CI, 1.17 to 6.83; p = 0.021). In patients treated with percutaneous coronary intervention, there was a high prevalence of OSA during REM sleep. Diabetes mellitus was an independent predictor of OSA during REM sleep.

Assessment of Neck Grasp as a Screening Tool for Identifying Obstructive Sleep Apnea in Community-Dwelling Older Adults.

BackgroundInability to encircle the neck by hands (neck grasp) has been proposed as an indicator of obstructive sleep apnea (OSA) that would be useful for recognition of candidates for polysomnography (PSG). We assessed the value of neck grasp for predicting OSA in community-dwelling older adults of Amerindian ancestry.MethodsNeck grasp was evaluated in individuals aged ≥60 years undergoing PSG. The association between neck grasp and OSA was assessed by logistic regression models adjusted for relevant covariates. Mediation analysis was used to establish the proportion of the effect of the association between neck grasp and OSA, which is mediated by the neck circumference (a well-known OSA biomarker). Receiver operator characteristics curve analysis was used to estimate diagnostic accuracy of neck grasp for predicting OSA.ResultsOf 201 individuals undergoing PSG, 167 (83%) had the neck grasp test. The remaining 34 could not perform the test because of different factors. Neck grasp was positive in 127 (76%) cases, and 114 (68%) individuals had OSA (apnea-hypopnea index ≥5). Multivariate logistic regression models disclosed a significant association between neck grasp and OSA. The neck circumference was the single covariate remaining independently significant in these models. Neck grasp was not efficient at predicting OSA (sensitivity: 83.3%, specificity: 39.6%, positive predictive value: 0.75 and negative predictive value: 0.53). The area under the curve disclosed only a moderate predictive capability (61.5%) of neck grasp.ConclusionResults do not support the use of neck grasp as an independent predictor of OSA in the study population.

Snoring: a source of noise pollution and sleep apnea predictor.

Snoring is a highly prevalent condition associated with obstructive sleep apnea (OSA) and sleep disturbance in bed partners. Objective measurements of snoring in the community, however, are limited. The present study was designed to measure sound levels produced by self-reported habitual snorers in a single night. Snorers were excluded if they reported nocturnal gasping or had severe obesity (BMI > 35 kg/m2). Sound was measured by a monitor mounted 65 cm over the head of the bed on an overnight sleep study. Snoring was defined as sound ≥40 dB(A) during flow limited inspirations. The apnea hypopnea index (AHI) and breath-by-breath peak decibel levels were measured. Snore breaths were tallied to determine the frequency and intensity of snoring. Regression models were used to determine the relationship between objective measures of snoring and OSA (AHI ≥ 5 events/h). The area under the curve (AUC) for the receiver operating characteristic (ROC) was used to predict OSA. Snoring intensity exceeded 45 dB(A) in 66% of the 162 participants studied, with 14% surpassing the 53 dB(A) threshold for noise pollution. Snoring intensity and frequency were independent predictors of OSA. AUCs for snoring intensity and frequency were 77% and 81%, respectively, and increased to 87% and 89%, respectively, with the addition of age and sex as predictors. Snoring represents a source of noise pollution in the bedroom and constitutes an important target for mitigating sound and its adverse effects on bed partners. Precise breath-by-breath identification and quantification of snoring also offers a way to risk stratify otherwise healthy snorers for OSA.

Obstructive sleep apnea in Parkinson's disease: a study in 239 Chinese patients

ObjectiveOur objective was to explore the clinical characteristics of Parkinson's disease (PD) comorbidity with obstructive sleep apnea (OSA), explore the correlation between OSA and PD features and identify factors that are independent predictors of OSA in PD patients. MethodsIn sum, 239 PD patients were divided into two groups according to the presence of OSA (apnea–hypopnea index (AHI) score ≥5) (PD-OSA vs PD-non-OSA). Blinded to sleep apnea status, participants underwent an extensive assessment to determine demographic features, concomitant disease, disease severity, polysomnography (PSG) characteristics and non-motor symptoms (NMSs). ResultsOf the 239 patients, 66 (27.62%) had an AHI score ≥5, including 14.2% (34/239) with mild, 6.7% (16/239) with moderate, and 6.7% (16/239) with severe sleep apnea. The binary logistic regression analyses indicated that age and male gender were risk factors for OSA, while rapid eye movement (REM) sleep disorder (RBD) and higher Levodopa equivalent dose (LED) were protective factors for OSA. PD-OSA patients had higher Epworth Sleepiness Scale (ESS) scores than those of PD-non-OSA patients. No differences were found for other NMSs between groups. ConclusionOur data suggest that OSA in PD was lower in patients with RBD and higher LED. RBD and higher LDEs were significant protective factors for OSA in PD. OSA in PD was increased with age and male gender. Age and male gender were risk factors for OSA in PD. OSA can aggravate excessive daytime somnolence in PD patients but is not associated with other NMSs.

Predictors of obstructive sleep apnea in lung transplant recipients

BackgroundThe aim of our study was to determine the prevalence and clinical predictors of obstructive sleep apnea in lung transplantation recipients. MethodsIn a cross-sectional analysis we studied 77 clinically stable lung transplant recipients (45 men, time range after lung transplantation [LTX]: from one month to 15 years). Indications for LTX were 36 chronic obstructive lung disease (COPD), 27 idiopathic pulmonary fibrosis (IPF), eight cystic fibrosis, and six others. In-lab polysomnography (PSG) was performed to investigate sleep characteristics. Obstructive sleep apnea (OSA) and central sleep apnea were defined by an apnea–hypopnea index (AHI) ≥ 10/h. ResultsThe prevalence of OSA and central sleep apnea (CSA) were 42.9% and 6.5%, respectively. OSA was present in 61% of patients with pre-transplant COPD and 52% of patients with pre-transplant IPF. Univariate analysis showed that OSA was significantly associated with neck circumference per 1-cm size increment (odds ratio [OR] = 1.21, 95% confidence interval [CI] = 1.04–1.42, p = 0.01) and pre-transplant COPD/IPF vs other lung diseases (cystic fibrosis, pulmonary arterial hypertension, α-1 antitrypsin deficiency, and lymphangioleiomyomatosis) (OR = 6.89, 95% CI = 1.41–33.56, p = 0.02), whereas age ≥57 years (OR = 1.76, 95% CI = 0.69–4.48, p = 0.24), male gender (OR = 2.33, 95% CI = 0.89–6.01, p = 0.08), and BMI ≥ 24.6 kg/m2 (OR = 1.73, 95% CI = 0.68–4.40, p = 0.25) did not reach a level of statistical significance. In a multivariate analysis neck circumference per 1-cm size increment (OR = 1.20, 95% CI = 1.02–1.41, p = 0.025) and pre-transplant COPD/IPF (OR = 5.34, 95% CI = 1.01–28.13, p = 0.048) remained independently associated with OSA. ConclusionsThe prevalence of OSA is high in stable lung transplant recipients. Pre-transplant COPD is an independent predictor of OSA.

Identifying obstructive sleep apnea after stroke/TIA: evaluating four simple screening tools

ObjectiveDespite its high prevalence and unfavorable clinical consequences, obstructive sleep apnea (OSA) often remains underappreciated after cerebrovascular events. The purpose of our study was to evaluate the clinical utility of four simple paper-based screening tools for excluding OSA after stroke or transient ischemic attack (TIA). Patients/MethodsSixty-nine inpatients and outpatients with stroke or TIA during the past 180 days completed the 4-Variable screening tool (4V), STOP-BAG questionnaire (ie, STOP-BANG questionnaire without the neck circumference measurement), Berlin questionnaire, and the Sleep Obstructive apnea score optimized for Stroke (SOS). They subsequently underwent objective testing using a portable sleep monitoring device. Cutoffs were selected to maximize sensitivity and exclude OSA (AHI ≥ 10) in ≥10% of the cohort. ResultsThe mean age was 68.3 ± 14.2 years and 47.8% were male. Thirty-two patients (46.4%) were found to have OSA. Male sex, body mass index (BMI), and atrial fibrillation were independent predictors of OSA. Among the screening tools, the 4V had the greatest area under the curve (AUC) of 0.688 (p = 0.007); the sensitivity was 96.9% for a cutoff of <6. The STOP-BAG also significantly detected OSA with an AUC of 0.677 (p = 0.012); the sensitivity was 93.8% for a cutoff of <2. Scores on the 4V and STOP-BAG were significantly correlated with the AHI. ConclusionsThe 4V and STOP-BAG questionnaire may aid clinicians with ruling out OSA within 180 days of stroke/TIA. Due to the atypical presentation of poststroke/TIA OSA, these tools are only moderately predictive; objective testing should still be used for OSA diagnosis in this population.

Serum sLOX-1 Levels Are Correlated with the Presence and Severity of Obstructive Sleep Apnea.

Inflammation plays a critical role in the development and progression of obstructive sleep apnea (OSA). Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) activation is involved in the pathophysiology of inflammatory process-related disorders. This study aims to investigate whether serum soluble LOX-1 (sLOX-1) levels are associated with the presence and severity of OSA. A total of 137 OSA patients and 78 controls were recruited in this study. Serum sLOX-1 levels were measured by enzyme-linked immunosorbent assay. The severity of OSA was assessed by the apnea-hypopnea index (AHI). OSA patients had significantly higher serum sLOX-1 levels compared with controls. Serum sLOX-1 levels elevated with the increment of OSA severity. sLOX-1 was the independent predictor of OSA. Serum sLOX-1 levels were significantly correlated with AHI and high-sensitivity C-reactive protein levels. Serum sLOX-1 levels were independently correlated with the presence and severity of OSA. These findings revealed that sLOX-1 might function as a potential biomarker for monitoring the development and progression of OSA.

The association of neutrophil to lymphocyte ratio with presence and severity of obstructive sleep apnea.

Obstructive sleep apnea (OSA) is characterized by reductions in breathing amplitude during sleep caused by an obstructed or collapsed upper airway. The neutrophil to lymphocyte ratio (NLR) has been proposed as a novel biomarker for systemic inflammatory response. The aim of the present study was to evaluate the relationship between NLR and OSA. The study population consisted of 195 consecutive patients with clinical suspicion of OSA. Full night polysomnography was performed for all patients. Patients with an apnea hypopnea index (AHI) ≥ 5 were considered to have OSA. NLR was calculated as the ratio of neutrophil count to lymphocyte count. While 130 patients (91 male, mean age: 49.9±9.8 years) had OSA, 65 patients (42 male, mean age: 48.7 ± 10.2 years) had normal findings according to AHI scores. Cardiovascular risk factors such as hypertension, hyperlipidemia, diabetes mellitus and smoking were more common in patients with OSA. Patients with OSA had significantly higher NLR than controls (1.87±0.80 vs 1.49±0.48, p=0.005). AHI score was significantly correlated with NLR (r=0.228, p=0.001). NLR and presence of hyperlipidemia were independent predictors of OSA (OR: 2.451, 2.850, p=0.001, 0.004, respectively). NLR of 1.62 or higher predicted OSA with a sensitivity of 56.2 % and specificity of 63.1 %. NLR was higher and also correlated with AHI score in patients with OSA which has not been reported previously. NLR more than 1.62 was an independent predictor of OSA. A simple, cheap white blood cell count may also give an idea about the presence and severity of OSA (Tab. 3, Fig. 3, Ref. 30).

Does neck-to-waist ratio predict obstructive sleep apnea in children?

Central adiposity and large neck circumference are associated with obstructive sleep apnea (OSA) in adults but have not been evaluated in children as predictors of OSA. Study objectives were to determine whether (1) anthropometric measures including neck-to-waist ratio are associated with OSA in older children; (2) body fat distribution, measured by neck-to-waist ratio, is predictive of OSA in overweight/obese children. Cross-sectional study involving children 7-18 years scheduled to undergo polysomnography at a tertiary care children's hospital. OSA was defined as total apnea-hypopnea index > 5 events/h and/or obstructive apnea index > 1 event/h. Recursive partitioning was used to select candidate predictors of OSA from: age, sex, height and weight percentile, body mass index (BMI) z-score, neck-to-waist ratio, tonsil size, and Mallampati score. These were then evaluated using log binomial models and receiver operator characteristic analysis. Two hundred twenty-two participants were included; 133 (60%) were overweight/obese, 121 (55%) male,47 (21%) had OSA. Neck-to-waist ratio (relative risk [RR] 1.97 per 0.1 units, 95% CI 1.48 to 2.84) and BMI z-score (RR 1.63 per unit, 95% CI 1.30 to 2.05) were identified as independent predictors of OSA. Considering only overweight/obese children, neck-to-waist ratio (RR 2.16 per 0.1 units, 95% CI 1.79 to 2.59) and BMI z-score (RR 2.02 per unit, 95% CI 1.25 to 3.26) also independently predicted OSA. However, in children not overweight/obese, these variables were not predictive of OSA. Neck-to-waist ratio, an index of body fat distribution, predicts OSA in older children and youth, especially in those who were overweight/obese.

Mallampati score and pediatric obstructive sleep apnea.

Pediatric obstructive sleep apnea (OSA) is common, and a delay in diagnosis can lead to significant morbidity. Polysomnography (PSG) is the gold standard for the diagnosis of OSA. However, difficulty accessing PSG due to the relative shortage of sleep centers with pediatric expertise can lead to a delay in the diagnosis and management of OSA. To assess the utility of Mallampati score (sitting and supine) in predicting the presence and severity of OSA in children. A retrospective study of 158 children from a single pediatric sleep center. All patients had a PSG and a physical examination documenting Mallampati score. The Mallampati score, tonsillar size, age, sex, and apnea hypopnea index (AHI) were analyzed. Odds ratio of having pediatric OSA (AHI > 1) with increase in Mallampati score and tonsillar size were calculated. A significant correlation was found between Mallampati score, tonsillar size, and AHI. For every point increase in the Mallampati score, the odds ratio of having OSA increased by more than 6-fold. For every point increase in tonsillar size, the odds ratio of having OSA increased by more than 2-fold. Mallampati score and tonsillar size are independent predictors of OSA. Oral examination including Mallampati score and tonsillar size should be considered when evaluating a patient for OSA. They can be used to prioritize children who may need PSG.

The influence of timing of polysomnography on diagnosis of obstructive sleep apnea in patients presenting with acute myocardial infarction and stable coronary artery disease

BackgroundWe aimed to determine if timing of polysomnography (PSG) influences the diagnosis of obstructive sleep apnea (OSA) in acute myocardial infarction (AMI) or stable coronary artery disease (CAD). MethodsA total of 160 patients admitted with AMI or stable CAD were consecutively recruited for either in-hospital (n=80) or postdischarge (n=80) PSG. ResultsThe median time from admission to PSG for the in-hospital and postdischarge groups was 1day and 17days, respectively (P<.001). Overall, 59 patients (36.9%) were diagnosed with OSA (apnea–hypopnea index [AHI] ⩾15), and they were more likely to have diabetes mellitus (DM), hypertension, hyperlipidemia, chronic renal failure, and a greater body mass index (BMI) (P<.05 for all). The diagnosis of OSA was significantly higher (P=.037) in patients who had a PSG performed as an inpatient than those who had a PSG as an outpatient. There was a significant interaction between clinical presentation and the effect of PSG timing on the diagnosis of OSA (P=.003). For the patients presenting with AMI but not those with stable CAD, in-hospital PSG was an independent predictor of OSA (adjusted odds ratio, 3.84 [95% confidence interval, 1.42–10.41]; P=.008). ConclusionThe timing of PSG influenced the diagnosis of OSA in patients who presented with AMI but not in those who presented with stable CAD.

Do Patients with Obstructive Sleep Apnea have an Increased Risk of Desaturation During Induction of Anesthesia for Weight Loss Surgery?~!2010-04-13~!2010-05-05~!2010-06-25~!

Background: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.Methods: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.Results: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.Conclusions: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.

Clinical Predictors of Obstructive Sleep Apnea in Asian Bariatric Patients

Obstructive sleep apnea (OSA) is a common disorder in modern society and closely associated with obesity. Because OSA increases the likelihood of complications in the perioperative period, preoperative recognition is very important for bariatric patients. Polysomnography (PSG) remains the gold standard for diagnosis, but it is a time-consuming and expensive examination. Our study is aimed at identifying practical clinical predictors of OSA for bariatric patients. From April 2006 to December 2007, 101 morbid obese patients [41 men and 60 women, mean age 30.3 +/- 8.5, mean body mass index (BMI) 43.3 +/- 6.9] who underwent PSG before bariatric surgery were retrospectively studied. The severity of OSA was categorized by the apnea-hypopnea index (AHI) as follows: normal, 0 to 4.9; mild, 5 to 14.9; moderate, 15 to 29.9; and severe, >/=30. Chi-squared tests and linear regression models were used to assess associations between clinical parameters and AHI; P < 0.05 was considered statistically significant. The mean Epworth sleepiness scale (ESS) score was 8.2 +/- 4.7, and the mean AHI was 28.9 +/- 33.8 per hour. Of 101 patients, 83 patients had OSA; including severe (32.7%), moderate (17.8%), and mild (31.7%) OSA; 18.5% had no OSA. Patients with severe OSA are significantly male predominant and had higher BMI, systolic blood pressure, hemoglobin, neck and waist circumference, and ESS scores. In linear regression model analysis, the parameters which positively correlated with AHI were body weight, BMI, systolic blood pressure, diastolic blood pressure, hemoglobin, waist and neck circumferences, and the scores of ESS. Multivariate analysis confirmed that BMI, neck circumference, and scores of ESS are independent predictors of the increasing of AHI. OSA is highly prevalent (82.2%) in Asian bariatric patients. BMI, neck circumference, and scores of ESS are independent predictors of OSA in these patients.

Prediction of obstructive sleep apnea in patients presenting to a tertiary care center

The objective of this prospective observational clinical study is to derive and validate a diagnostic model for prediction of obstructive sleep apnea (OSA) in subjects presenting with non-sleep-related complaints in a tertiary care center in north India. We included 102 subjects (group I, range 31-70 years) presenting to the hospital with non-sleep-related complaints. None of the subjects had any significant comorbid illness such as respiratory or congestive cardiac failure. All subjects underwent detailed evaluation including polysomnography (PSG). Various parameters were compared between the cases (apnea-hypopnea index, AHI > or =15/h) and controls (AHI <15/h). Using multivariate logistic regression analysis, a diagnostic model for prediction of OSA was derived. Subsequently, using similar selection criteria, 104 subjects (group II, range 32-68 years) were included for validation of the newly derived diagnostic model. Body mass index [BMI; OR (95% CI), 1.14(1.1-1.2)], male gender 5.0(1.4-27.1), relative-reported snoring index (SI) 2.8(1.7-5.0), and choking index (ChI) 8.1(1.4-46.5) were significant, independent predictors of OSA. Diagnostic model was computed as score = [1.61 x (gender)] + [1.01 x (S1)] + [2.09 x (ChI)] + [0.1 x (BMI)] where, gender: 0 = female, 1 = male and SI, ChI, BMI are actual values. The diagnostic model had an area under the receiver operator characteristics curve of 89.6%. A cutoff of 4.3 for the score was associated with sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of 91.3, 68.5, 70.5, and 92.3%, respectively. Misclassification rate with the application of the diagnostic model on group II subjects was 13.5% (14/104). Sensitivity, specificity, PPV, and NPV of the model for predicting OSA in this group were 82, 90.7, 89.1, and 84.5%, respectively. BMI, male gender, SI, and ChI are independent predictors of OSA. Diagnostic model derived from these parameters is useful for predicting presence of OSA and screening subjects for PSG.

Obstructive sleep apnea and the metabolic syndrome in community-based Chinese adults in Hong Kong

To investigate the relationship between obstructive sleep apnea (OSA) and the metabolic syndrome, an established cardiovascular risk factor, in middle-aged Chinese subjects. A prospective cross-sectional study from community-dwelling volunteers. Subjects of either sex between 30 and 60 years old were recruited from the staff in public institutions or visitors to community centers in Hong Kong. Demographic and anthropomentric indices, blood pressure and metabolic profile (fasting blood glucose, total cholesterol, low-density lipoprotein-cholesterol, high-density lipoprotein-cholesterol and triglycerides) were measured. Overnight polysomnographic studies were conducted. Presence of obstructive sleep apnea (OSA) was defined as apnea-hypopnea index (AHI)5. Metabolic syndrome was defined by the criteria of the National Cholesterol Education Panel, but using Asian cut-off values for abdominal obesity. A total of 255 subjects (150 men, 105 women) were studied. Subjects with OSA had five-fold risk of having metabolic syndrome. OSA was associated with the metabolic syndrome or its components, including waist circumference, diastolic blood pressure and fasting glucose, after adjusting for confounding variables. The independent determinants of OSA were age, gender, body mass index (BMI) and the metabolic syndrome. Among community-based middle-aged Chinese subjects, the metabolic syndrome was independent predictor of OSA.

A stepped approach for prediction of obstructive sleep apnea in overtly asymptomatic obese subjects: a hospital based study

Background and purpose: Prevalence of obstructive sleep apnea (OSA) is high in obese subjects, many of whom may not be overtly symptomatic. Polysomnography (PSG) is a costly and time-consuming investigation. Since it is not feasible to subject all obese individuals to PSG, it is useful to define predictors of OSA among these subjects. Patients and methods: One hundred and eighteen obese subjects [body mass index (BMI)≥25 kg/m 2] presenting to the hospital with non-sleep related complaints were included, of which 53 subjects with PSG evidence of OSA [apnea-hypopnea index (AHI)≥15/h] were defined as cases and 65 subjects without any evidence of OSA (AHI<15/h) were defined as controls. Anthropometry, biochemical investigations, blood gas analysis, pulmonary function tests, and PSG were performed for all subjects. Results: Waist hip ratio (WHR) (as percentage of a standard) [odds ratio (95% CI): 1.07 (1.00–1.14); P=0.049], male gender [odds ratio (95% CI): 3.97 (0.99–15.81); P=0.046] and neck circumference (NC) [odds ratio (95% CI): 1.23 (1.03–1.47); P=0.023] were found to be independent predictors of OSA. Overnight oxygen desaturation data were evaluated in patients selected as having OSA on the basis of these clinical markers, and the best cut-off for level of desaturation (10%) was defined. The stepped approach had a specificity, sensitivity, positive and negative predictive value of 89.2, 88.5, 86.8 and 90.6%, respectively, for the diagnosis of OSA. Conclusions: Male gender, WHR and NC are independent predictors of OSA in overtly asymptomatic obese subjects. A stepped approach to diagnose OSA should be used, as it is accurate and cost-effective.