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13 The effect of continuous positive airway pressure (CPAP) on key plasma metabolites identifying obstructive sleep apnoea hypopnoea syndrome (OSAHS)
  1. Scott O’Rourke1,
  2. Sarah Thomas2,
  3. Catrin Lewis1,
  4. Sarah Bowen1,
  5. Luis Mur2 and
  6. Keir Lewis1
  1. 1Prince Phillip Hospital, Llanelli, UK
  2. 2Aberystwyth University, Aberystwyth, UK


We recently applied untargeted metabolomic profiling on the plasma obtained from consecutive attenders referred for conventional Level 3 home-sleep studies with excessive daytime somnolence, comparing 17 OSAHS patients (AHI≥15, Epworth Score 13.5±4.5) with 16 age, gender, and BMI matched sleepy subjects (sleepy snorers (SS)) with negative home polysomnography tests (AHI<15, Epworth Score 12.1±7.0).1

We reported 6 biologically plausible plasma metabolites that can differentiate OSAHS from SS of similar phenotype with an AUC of 0.982 (95% CI: 0.9-1.0) (figure 1), with these key metabolites being essential lipids involved in protein synthesis and the formation of antioxidative, antiglycating, and free radical scavenging dipeptides. We now report early changes in these biomarkers following CPAP in those with OSAHS.

11 OSAHS patients with AHI≥15 (63.6% male, Age 54.4±6.9, BMI 34.2±4.0, AHI 47.6±25.6, Epworth 13.7±4.8) were commenced on standard auto-adjustment CPAP devices (Phillips DreamStation set at 4 to 18 cm H2O). Mean use of CPAP was 6.6±1.4 hours and average residual AHI was 6.9±6.0. Plasma was sampled pre and post treatment (42-70 days treatment), and metabolomically assessed using the Q Exactive Hybrid Quadrupole-Orbitrap mass spectrometry platform. 16 sleepy snorers with AHI<15 (75.0% male, Age 46.1±12.5, BMI 34.6±5.9, AHI 6.8±4.4, Epworth 12.1±7.0) were sampled at baseline only.

Our previously reported biomarkers associated with processes such as oxidative stress, inflammation, and dysregulation of energy homeostasis improve with short-term treatment with CPAP towards the level of sleepy snorers of similar age, phenotype, and no OSAHS (figure 2). We feel these metabolites have significant potential in the future care pathways of OSAHS, and could reflect the cardiometabolic risk associated with OSAHS better than current diagnostic modalities.

Abstract 13 Figure 1

Metabolomic discrimination between the plasma of OSAHS and SS patients

Abstract 13 Figure 2

Changes in key metabolites after period of CPAP


  1. O’Rourke, et al. Plasma metabolomics identifies OSAHS. ERS Congress 2021.

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