Screening for Obstructive Sleep Apnea in the Assessment of Coronary Risk.

There is increasing awareness that health screening may prevent some acute coronary events. Yet, obstructive sleep apnea (OSA) is seldom screened for and its relation with coronary risk markers is not well established. Consecutive adults (n = 696) enrolled in a cardiovascular health screening program were approached to determine the feasibility of incorporating OSA screening. Screening included questionnaires and a home-based sleep study. High-sensitivity C-reactive protein was the primary coronary risk marker, and other laboratory- and exercise treadmill-based markers were also reported. Two thirds of the participants (66%) agreed to undergo OSA screening and most (78%) successfully completed the sleep study. The prevalence of OSA (apnea-hypopnea index ≥15/hour) was 38.0%. The Berlin Questionnaire (53%) and Epworth Sleepiness Scale (26%) had low sensitivity in identifying OSA. After full adjustment for age, gender, body mass index, hypertension, and diabetes mellitus, OSA remained an independent predictor of serum levels of high-sensitivity C-reactive protein (relative mean difference 1.29, 95% CI 1.03 to 1.62; p = 0.025), triglyceride (relative mean difference 1.15, 95% CI 1.03 to 1.28; p = 0.014), and exercise time (mean difference -26.4 seconds; 95% CI -51.6 to -1.2; p = 0.04). The INTERHEART Risk Score analysis suggested more participants with (31%) than without (14%, p <0.001) OSA will develop future cardiovascular events. In conclusion, based on the acceptance for OSA screening, high prevalence of OSA and independent associations between OSA and coronary risk markers, incorporation of sleep studies into cardiovascular health screening programs appears feasible.

Validation of NoSAS score for screening of sleep-disordered breathing in a multiethnic Asian population.

PURPOSE: The NoSAS score was developed to identify subjects at high risk of sleep-disordered breathing (SDB). We aimed to validate the NoSAS score in a multiethnic Asian cohort and compare its performance to the STOP-Bang and Berlin questionnaires. METHODS: A sample of 242 subjects selected from a population-based cohort in Singapore completed home-based sleep testing with an Embletta device (type 3 monitor). All subjects were given the STOP-Bang and Berlin questionnaires for self-administration prior to the sleep study. The NoSAS score was subsequently calculated based on available demographic data and Berlin questionnaire responses. RESULTS: The prevalence of severe SDB, defined as an apnea-hypopnea index cutoff of ≥30 events/h, was 10.7%. The number of subjects who were classified as high risk by the NoSAS score and STOP-Bang and Berlin questionnaires were 76 (31.4%), 89 (36.8%), and 79 (32.6%), respectively. The sensitivity, specificity, and negative and positive predictive values of the NoSAS score to predict severe SDB were 69.2, 73.1, 95.2, and 23.7%, respectively. The STOP-Bang and Berlin questionnaires performed similarly to the NoSAS score, with area under the curve (AUC) values of all three questionnaires clustered around 0.682-0.748. Compared to the STOP-Bang (94.8%) and Berlin questionnaires (96.3%), the NoSAS score (95.2%) had equally high negative predictive value in ruling out severe SDB. CONCLUSIONS: The NoSAS score performed similarly to the STOP-Bang and Berlin questionnaires in a multiethnic Asian cohort. All three questionnaires had high negative predictive values in ruling out severe SDB and may have utility as screening tools.

Using the Berlin Questionnaire to Predict Obstructive Sleep Apnea in the General Population.

STUDY OBJECTIVES: The Berlin questionnaire is a self-administered questionnaire that was developed to identify subjects with obstructive sleep apnea (OSA) in primary care settings. This study evaluated the performance of the questionnaire to predict OSA in the general population. METHODS: A sample of 242 subjects in a population-based cohort completed a home-based sleep study with an Embletta device (type 3 monitor). Subjects completed the Berlin questionnaire on the evening just prior to the sleep study. The sleep studies were manually scored according to the 2012 American Academy of Sleep Medicine (AASM) criteria. RESULTS: The prevalence of moderate-to-severe and severe OSA defined as apnea-hypopnea index (AHI) of ≥ 15 and ≥ 30 was 28.1% and 10.7%, respectively. Seventy-nine subjects (32.6%) were classified as high risk according to the Berlin questionnaire. The sensitivity, specificity, negative predictive value (NPV), and positive predictive value (PPV) of the questionnaire to predict an AHI ≥ 15 was 58.8%, 77.6%, 82.9%, and 50.6%, respectively. The area under the receiving operator characteristic (ROC) curve for moderate-to-severe OSA was 0.682. When used to predict an AHI ≥ 30, the sensitivity of the questionnaire increased to 76.9% with a small drop in specificity to 72.7%. The corresponding NPV, PPV, and area under the ROC curve of the questionnaire to predict severe OSA were 96.3%, 25.3%, and 0.748, respectively. CONCLUSIONS: The Berlin questionnaire may have utility in the general population setting as a screening tool for OSA in view of its good sensitivity and high NPV in ruling out severe OSA.

Predicting obstructive sleep apnea using the STOP-Bang questionnaire in the general population.

OBJECTIVE: The STOP-Bang questionnaire was developed as a quick and simple screening tool for obstructive sleep apnea (OSA) in preoperative clinics. We aimed to evaluate the validity of the STOP-Bang questionnaire to predict moderate-to-severe and severe OSA in the general population. METHODS: A sample of 242 subjects selected from a population-based cohort in Singapore completed home-based sleep testing with a type 3 monitor. Subjects were asked to complete the STOP questionnaire while body mass index (BMI), age, neck circumference, and sex were recorded. A score of ≥3 on the questionnaire indicated high risk of OSA. RESULTS: A total of 68 subjects (28.1%) and 26 subjects (10.7%) had an apnea-hypopnea index (AHI) of ≥15 and ≥30 events per hour, respectively. Of the subjects, 89 (36.8%) were classified as high risk based on the questionnaire. The sensitivity of a STOP-Bang score of ≥3 was 66.2% to detect AHI ≥15 and 69.2% to detect AHI ≥30. The specificities were 74.7% and 67.1%, respectively. The negative predictive values were 85% for moderate-to-severe OSA and 94.8% for severe OSA. The corresponding positive predictive values were 50.6% and 20.2%, respectively. Using BMI cutoffs of 30 and 27.5 for Asians compared to the original cutoff of 35 did not improve the questionnaire performance significantly. CONCLUSION: The STOP-Bang questionnaire can be used as a screening tool in the general population in view of its moderate sensitivity and high negative predictive value for subjects with moderate-to-severe and severe OSA. The cutoff of BMI >35 can be used in Asians, as lower BMI cutoffs did not improve questionnaire performance.

Prevalence of sleep-disordered breathing in a multiethnic Asian population in Singapore: A community-based study.

BACKGROUND AND OBJECTIVE: Limited data exist on the prevalence variation in sleep-disordered breathing (SDB) across different Asian ethnicities. This population study aimed to estimate the prevalence of SDB in Singapore, a multiethnic nation, and to quantify the prevalence variation among Chinese, Malays and Indians. METHODS: The Singapore Health Study 2012 was a cross-sectional population study conducted on adults aged 21-79 years. Among 2329 participants who completed baseline examination, a sample of 242 subjects completed home-based sleep testing with an Embletta device (type 3 monitor). Moderate-to-severe SDB, defined as an apnoea-hypopnoea index (AHI) of ≥15 events/h, was used to estimate prevalence. RESULTS: The weighted estimates of the population prevalence of moderate-to-severe SDB and sleep apnoea syndrome were 30.5% and 18.1%, respectively. Of subjects with AHI ≥15, 91.0% were previously undiagnosed. Moderate-to-severe SDB prevalence varied across the Chinese (32.1%), Malays (33.8%) and Indians (16.5%). The mean body mass index (BMI) was lowest in Chinese (23.3 kg/m(2) ) and highest among Malays (26.0 kg/m(2) ) and Indians (25.4 kg/m(2) ). Compared with Chinese, Indians had lower odds of moderate-to-severe SDB after adjustment for age, sex and BMI (odds ratio 0.82, 95% CI: 0.70-0.96, P = 0.02). CONCLUSION: Sleep-disordered breathing is prevalent but mostly undiagnosed among Asians in Singapore. There was a lower prevalence of SDB among Indians compared with Chinese that remained after adjustment for age, sex and BMI. Strategies are needed to optimize diagnosis and recognize ethnic differences in SDB prevalence.

Antiviral activity of lanatoside C against dengue virus infection.

Dengue infection poses a serious threat globally due to its recent rapid spread and rise in incidence. Currently, there is no approved vaccine or effective antiviral drug for dengue virus infection. In response to the urgent need for the development of an effective antiviral for dengue virus, the US Drug Collection library was screened in this study to identify compounds with anti-dengue activities. Lanatoside C, an FDA approved cardiac glycoside was identified as a candidate anti-dengue compound. Our data revealed that lanatoside C has an IC50 of 0.19µM for dengue virus infection in HuH-7 cells. Dose-dependent reduction in dengue viral RNA and viral proteins synthesis were also observed upon treatment with increasing concentrations of lanatoside C. Time of addition study indicated that lanatoside C inhibits the early processes of the dengue virus replication cycle. Furthermore, lanatoside C can effectively inhibit all four serotypes of dengue virus, flavivirus Kunjin, alphavirus Chikungunya and Sindbis virus as well as the human enterovirus 71. These findings suggest that lanatoside C possesses broad spectrum antiviral activity against several groups of positive-sense RNA viruses.