title: Optimal Body Mass Index Cut-offs for Identification of Patients with Coronary Artery Disease at High Risk of Obstructive Sleep Apnoea.
abstract: BACKGROUND
  We sought to evaluate the relationship between Body Mass Index (BMI) and obstructive sleep apnoea (OSA) in Chinese patients hospitalised with coronary artery disease, and to determine the optimal BMI cut-off for prediction of OSA.
  
  
  METHODS
  Consecutive Chinese patients who were hospitalised with symptomatic coronary artery disease were recruited to undergo an in-hospital sleep study.
  
  
  RESULTS
  A total of 587 patients were recruited. Using cut-off for Asians, 81.2% of the cohort was overweight (BMI ≥23kg/m(2)) and 31.6% was obese (≥27kg/m(2)). A total of 59.5% was diagnosed with OSA, defined as apnoea-hypopnoea index ≥15. Body mass index, hypertension and smoking were predictors of OSA. Multiple logistic regression analysis showed that BMI remains an independent predictor of OSA (odds ratio: 1.11 [95% confidence interval: 1.06 to 1.17], p<0.001) after adjusting for smoking and hypertension. Further analysis using BMI and Apnoea-Hypopnoea Index (AHI) as continuous variables showed significant correlation between BMI and AHI (Pearson's r =0.25, P<0.001). In adjusted models, optimal BMI cut-offs to screen for OSA were 27.3kg/m(2), 23.0-23.9kg/m(2), and 20kg/m(2) for patients with neither, either, or both predictors (smoking and hypertension) respectively. The area under the curve for the adjusted and unadjusted models were similar (0.6013 vs 0.6262, p=0.118).
  
  
  CONCLUSIONS
  Body mass index represents a convenient and readily available tool for bedside identification of patients at high risk of OSA. Body mass index cut-offs to predict risks of OSA in Chinese patients with symptomatic coronary artery disease are defined in this study.
authors.affiliation: Department of Cardiology, National University Heart Centre Singapore, Singapore.
authors.forename: Po-Fun
authors.initials: PF
authors.lastname: Chan
authors.affiliation: Saw Swee Hock School of Public Health, National University of Singapore, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Bee-Choo
authors.initials: BC
authors.lastname: Tai
authors.affiliation: Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
authors.forename: Germaine
authors.initials: G
authors.lastname: Loo
authors.affiliation: Department of Cardiology, National University Heart Centre Singapore, Singapore.
authors.forename: Chieh-Yang
authors.initials: CY
authors.lastname: Koo
authors.affiliation: Department of Respiratory and Critical Care Medicine, Singapore General Hospital, Singapore.
authors.forename: Thun-How
authors.initials: TH
authors.lastname: Ong
authors.affiliation: Department of Cardiology, National University Heart Centre Singapore, Singapore.
authors.forename: Tiong-Cheng
authors.initials: TC
authors.lastname: Yeo
authors.affiliation: Department of Cardiology, National University Heart Centre Singapore, Singapore; Yong Loo Lin School of Medicine, National University of Singapore, Singapore. Electronic address: mdclchr@nus.edu.sg.
authors.forename: Chi-Hang
authors.initials: CH
authors.lastname: Lee
mesh_terms: D000368:Aged; D015992:Body Mass Index; D003324:Coronary Artery Disease / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology; D011446:Prospective Studies; D012307:Risk Factors; D020181:Sleep Apnea, Obstructive / Q000150:complications / Q000175:diagnosis / Q000503:physiopathology
keywords: Cardiovascular; Clinical decision making; Ethnicity; Obesity; Overweight; Prediction