title: Obesity as an Effect Modifier in Sleep-Disordered Breathing and Postcardiac Surgery Atrial Fibrillation.
abstract: Because the interrelationships of objectively ascertained sleep-disordered breathing (SDB), postcardiac surgery atrial fibrillation (PCSAF), and obesity remain unclear, we aimed to further investigate the interrelationships in a clinic-based cohort.
  
  
  
  Patients with polysomnography and cardiac surgery (coronary artery bypass surgery and/or valvular surgery) within 3 years, from January 2009 to January 2014, were identified, excluding those with preexisting atrial fibrillation. Logistic models were used to determine the association of SDB (apnea hypopnea index [AHI] per 5-unit increase) and secondary predictors (central sleep apnea [CSA] [central apnea index ≥ 5] and oxygen desaturation index [ODI]) with PCSAF. Models were adjusted for age, sex, race, BMI, and hypertension. Statistical interaction and stratification by median BMI was performed. ORs and 95% CIs are presented.
  
  
  
  There were 190 patients who comprised the analytic sample (mean age, 60.6 ± 11.4 years; 36.1% women; 80% white; BMI, 33.3 ± 7.5 kg/m2; 93.2% had an AHI ≥ 5; 30% had PCSAF). Unlike unadjusted analyses (OR, 1.06; 95% CI, 1.01-1.1), in the adjusted model, increasing AHI was not significantly associated with increased odds of PCSAF (OR, 1.04; 95% CI, 0.98-1.1). Neither CSA nor ODI was associated with PCSAF. A significant interaction with median BMI was noted (P = .015). Effect modification by median BMI was observed; those with a higher BMI > 32 kg/m2had 15% increased odds of PCSAF (OR, 1.15; 95% CI, 1.05-1.26; P < .003).
  
  
  
  SDB was significantly associated with PCSAF in unadjusted analyses, but not after taking into account obesity; those with both SDB and obesity may represent a vulnerable subgroup to target to reduce PCSAF and its associated morbidity.
authors.affiliation: Hospital Medicine and Outcomes Research, Anesthesiology, Cleveland Clinic, Cleveland, OH.
authors.forename: Roop
authors.initials: R
authors.lastname: Kaw
authors.affiliation: Sleep Disorders Center, Neurologic Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Samer
authors.initials: S
authors.lastname: El Zarif
authors.affiliation: Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: Lu
authors.initials: L
authors.lastname: Wang
authors.affiliation: Quantitative Health Sciences, Lerner Research Institute, Cleveland Clinic, Cleveland, OH.
authors.forename: James
authors.initials: J
authors.lastname: Bena
authors.affiliation: Thoracic and Cardiovascular Surgery and Quantitative Health Sciences, Cleveland Clinic, Cleveland, OH.
authors.forename: Eugene H
authors.initials: EH
authors.lastname: Blackstone
authors.affiliation: Sleep Disorders Center, Neurologic Institute, Cleveland Clinic, Cleveland, OH; Department of Molecular Cardiology, Lerner Research Institute, Cleveland Clinic, Cleveland, OH; Respiratory Institute and Heart and Vascular Institute, Cleveland Clinic, Cleveland, OH. Electronic address: mehrar@ccf.org.
authors.forename: Reena
authors.initials: R
authors.lastname: Mehra
mesh_terms: D000368:Aged; D001281:Atrial Fibrillation / Q000453:epidemiology*; D006348:Cardiac Surgical Procedures; D001026:Coronary Artery Bypass; D005260:Female; D006351:Heart Valves / Q000601:surgery; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology*; D017286:Polysomnography; D011183:Postoperative Complications / Q000453:epidemiology*; D012307:Risk Factors; D012891:Sleep Apnea Syndromes / Q000453:epidemiology*; D020182:Sleep Apnea, Central / Q000453:epidemiology
keywords: atrial fibrillation; cardiac surgery; obesity; sleep apnea