title: Validation of the Nox-T3 Portable Monitor for Diagnosis of Obstructive Sleep Apnea in Chinese Adults.
abstract: OBJECTIVE
  To evaluate the performance of a portable monitor (Nox-T3, Nox Medical Inc. Reykjavik, Iceland) used to diagnose obstructive sleep apnea in Chinese adults.
  
  
  METHODS
  Eighty Chinese adults (mean ± standard deviation age 47.6 ± 14.0 years, 77.5% males, body mass index 27.5 ± 5.4 kg/m2) underwent overnight, unattended home sleep apnea testing (HSAT) with the Nox-T3 portable monitor followed by an overnight in-laboratory polysomnogram (PSG) with simultaneous portable monitor recording. The portable monitor recordings were scored using automated analysis and then manually edited using different criteria for scoring hypopneas. Polysomnography was scored based on recommended guidelines.
  
  
  RESULTS
  When scoring of hypopneas required a ≥ 4% oxygen desaturation event, the mean ± standard deviation apnea-hypopnea index (AHI) was 24.4 ± 20.8 events/h on HSAT, 28.0 ± 22.9 events/h on in-laboratory portable monitor recording, and 28.6 ± 23.9 events/h on PSG (P< .0001). Bland-Altman analysis of AHI on PSG versus HSAT showed a mean difference (95% confidence interval) of -4.64 (-7.15, -2.13); limits of agreement (equal to ± 2 standard deviations) was -26.62 to 17.35 events/h. Based on a threshold of AHI ≥ 5 events/h, HSAT had 95% sensitivity, 69% specificity, 94% positive predictive value, and 75% negative predictive value compared to PSG. Using an AHI ≥ 15 events/h, HSAT had 93% sensitivity, 85% specificity, 89% positive predictive value, and 91% negative predictive value. Closer agreements were present when comparing the simultaneous recordings. Similar results were obtained using different scoring criteria for hypopneas.
  
  
  CONCLUSIONS
  Despite known differences between HSAT and PSG, the results show close agreement between the two diagnostic tests in Chinese adults, especially when controlling for night-to-night variability and changes in sleeping environment.
authors.affiliation: PKU-UPenn Sleep Center, Peking University International Hospital, Beijing, China.
authors.forename: Liyue
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Respiratory Medicine, Peking University People's Hospital, Beijing, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Han
authors.affiliation: Department of Medicine and Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Brendan T
authors.initials: BT
authors.lastname: Keenan
authors.affiliation: Department of Medicine and Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Kneeland-Szanto
authors.affiliation: Department of Respiratory Medicine, Peking University People's Hospital, Beijing, China.
authors.forename: Han
authors.initials: H
authors.lastname: Yan
authors.affiliation: Department of Respiratory Medicine, Peking University People's Hospital, Beijing, China.
authors.forename: Xiaosong
authors.initials: X
authors.lastname: Dong
authors.affiliation: PKU-UPenn Sleep Center, Peking University International Hospital, Beijing, China.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Chang
authors.affiliation: Department of Respiratory Medicine, Peking University People's Hospital, Beijing, China.
authors.forename: Long
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Respiratory Medicine, Peking University People's Hospital, Beijing, China.
authors.forename: Xueli
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Respiratory Medicine, Peking University People's Hospital, Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Medicine and Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Philadelphia, Pennsylvania.
authors.forename: Allan I
authors.initials: AI
authors.lastname: Pack
authors.affiliation: Department of Medicine and Center for Sleep and Circadian Neurobiology, University of Pennsylvania, Philadelphia, Pennsylvania.|Department of Medicine, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania.
authors.forename: Samuel T
authors.initials: ST
authors.lastname: Kuna
mesh_terms: D002681:China; D004867:Equipment Design; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory / Q000295:instrumentation* / Q000379:methods*; D017286:Polysomnography / Q000295:instrumentation* / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis*
keywords: apnea-hypopnea index; home sleep apnea testing; polysomnography