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Overnight pulse oximetry for screening of obstructive sleep apnea in at-risk adult patients in the primary care setting: prospective case series
  1. Lap-Kin Chiang1,
  2. Cheuk-Wai Kam1 and
  3. Lorna V. Ng1
  1. 1. Family Medicine and General Outpatient Department Kwong Wah Hospital, Hong Kong
  1. Corresponding Author: Lap-Kin Chiang Family Medicine and General Outpatient Department, 1/F, Tsui Tsin Tong Outpatient Building, Kwong Wah Hospital, 25 Waterloo Road, Mongkok, Hong Kong Tel.: +852-35-172301 Fax: +852-35-172401 E-mail: chialk{at}


Objective To estimate prevalence of OSA among at risk adult patients in primary care setting. To test the correlation and agreement between overnight pulse oximetry and polysomnography (PSG). To test the OSA screening performance of overnight pulse oximetry.

Design and Setting Prospective case series involving adult Chinese patients with risk factors for OSA at a primary care clinic of Hong Kong.

Methods The prevalence and severity of OSA were established based on overnight pulse oximetry derived oxygen desaturation index (ODI). Screening performance of overnight pulse oximetry was compared directly with gold standard diagnostic test PSG.

Results Three hundred and five male and 229 female patients were recruited. Snoring (48.3%) was the top presenting symptom. Three hundred and twenty five patients (60.9%) were screened positive to have OSA. One hundred and nine patients had performed PSG, the ODI_4 and apnoea-hypopnea index (AHI) had Pearson correlation coefficient 0.71 (P<0.001). Bland and Altman plot showed good agreement. Using designation criteria of ODI_4≥5 events/hr, the sensitivity and specificity for OSA diagnosis are 94.4% and 78.9% respectively.

Conclusion The prevalence of OSA is 60.9% among adult primary care population who are at risk for OSA. Overnight pulse oximetry shows good performance as a screening tool for the screening of OSA.

  • Obstructive sleep apnea
  • overnight pulse oximetry
  • primary care

This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 Unported License (CC BY-NC 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. See

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