title: Diagnostic accuracy of home-based monitoring system in morbidly obese patients with high risk for sleep apnea.
abstract: BACKGROUND
  No previous studies have validated the use of portable monitoring (PM) for the diagnosis of obstructive sleep apnea (OSA) in morbidly obese individuals. Our aim was to investigate the accuracy of PM for detecting respiratory events in morbidly obese patients that will be undergoing bariatric surgery.
  
  
  METHODS
  This was a prospective study involving patients with body mass index (BMI) ≥35 kg/m(2) who were recruited from the Sleep Clinic of Universidade Federal de São Paulo. Sleep-disordered breathing (SDB) was evaluated during full-night polysomnography (PSG). PM use was randomized and used on two consecutive nights: (1) at home (STDHome) and (2) at the sleep laboratory with PSG (PSG_STDLab).
  
  
  RESULTS
  Although 58 participants initially underwent the recordings, 26 (45%) were excluded because of technical problems. The patients' mean age was 42.9 ± 10.9 (SD) years, and 56% were female. The mean BMI was 40.8 ± 5.2 kg/m(2). All patients had high risk for OSA, as defined by the Stop-Bang questionnaire, and the mean apnea-hypopnea index (AHI) was 46.9 ± 30.4/h. The intraclass coefficient of the correlation between AHI_PSG and AHI_STDLab was r = 0.92 (p = 0.0001); the intraclass coefficient for AHI_PSG and AHI_STDHome was r = 0.84 (p = 0.0001). The Kappa index was 0.87 (p > 0.0001) for severe cases. The sensitivity and the positive predictive value increased with the disease severity. A Bland-Altman analysis showed good agreement between the investigated methods.
  
  
  CONCLUSIONS
  PM is an efficacious method for diagnosing OSA in obese patients who have a high clinical probability of the disease. The method displays good sensitivity and specificity in severe cases; nevertheless, the high rate of data loss must be taken into account.
authors.affiliation: Disciplina de Pneumologia, Departamento de Medicina, Universidade Federal de Sao Paulo - UNIFESP, Rua Pedro de Toledo, 720, Sao Paulo, SP, 04039-034, Brazil, oliveira_marcia@hotmail.com.
authors.forename: Márcia G
authors.initials: MG
authors.lastname: Oliveira
authors.forename: Erika C
authors.initials: EC
authors.lastname: Treptow
authors.forename: Cesar
authors.initials: C
authors.lastname: Fukuda
authors.forename: Luiz E
authors.initials: LE
authors.lastname: Nery
authors.forename: Rosana M
authors.initials: RM
authors.lastname: Valadares
authors.forename: Sérgio
authors.initials: S
authors.lastname: Tufik
authors.forename: Lia
authors.initials: L
authors.lastname: Bittencourt
authors.forename: Sonia M
authors.initials: SM
authors.lastname: Togeiro
mesh_terms: D000328:Adult; D015992:Body Mass Index; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009767:Obesity, Morbid / Q000453:epidemiology*; D017286:Polysomnography / Q000379:methods*; D011446:Prospective Studies; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000453:epidemiology